Janneke Martens Human Perception Samenvatting - foundation of sensation and perception Hoofdstuk 1 The cerbral cortex is devoted entirely to perception. Prosopagnosia: a clinical condition resulting from brain damage, in which a patient is unable to recognize familiar faces. Psychophysics: The scientific study of the relationship between physical stimulation and perceptual experience. Sense Vision Stimulus Electromagnetic energy Air pressure waves Tissue distortion Hearing Touch Balance Taste/Smell Gravity, acceleration Chemical composition Receptor Photoreceptors Sensory structure Eye Mechanoreceptors Ear Mechanoreceptors, Skin, muscle, etc. thermoreceptors Mechanoreceptors Vestibular organs Chemoreceptors Nose, mouth Cortex Primary visual cortex Auditory cortex Somatonsensory cortex Temporal cortex Primary taste cortex, olfactory cortex Zie ook figure 1.2 on page 5 for the receiving areas Transduction: The process by which sensory receptor cells convert environmental energy into electrical neural signals. Cerebral cortex: The outer layer of the human brain: approximately 2.5 mm thick, it contains the millions of neurons thought to underlie conscious perceptual experience. Different methods to study perception • • • Lesion experiments: surgically remove or destroy a specific area of a brain, and then observe the consequences for behavior. Played an important part in localization of function: The view that neurons underlying a specific sensory or cognitive function are located in a circumscribed brain area. Lesion: An abnormality in structure or function in any part of the body. Clinical studies: the same as lesion experiments, but then with human brain damage by accident or something. Concluding form this is limited, because the researcher has no control over the circumstances. Single-unit recordings: (Electrical Field Theory of perception: ???) It discovered with microelectrode recording the functions of all the different brain cells they are all specialized although they look the same. It is not correct to think that individual neurons in the brain act as detectors for individual stimulus features. 1 Janneke Martens • • • Topographic map: A spatial arrangement of neurons in a neural structure in which nearby cells respond to nearby locations in the visual field of view. Cells that prefer similar stimuli tend to be located near to each other. Brain imaging: primarily for the use in medicine. Computerized tomography (CT) scan: A medical technique in which X-rays are passed through the body at different angels, and the resulting data are processed by a computer to create detailed images of body structure. Magnetic resonance imaging (MRI): A medical technique in which short bursts of powerful radio waves are passed through the body at different angles, and signals emitted by body molecules are processed by a computer to create detailed images of body structure. Psychophysics: the scientific study of relationships between physical stimuli and perceptual phenomena. Useful for testing predictions from theories of perception. Artificial intelligence (AI): A branch of computer science that aims to produce a device capable of behavior normally associated with human cognition, such as language understanding, reasoning, and perception. Computation: The manipulation of quantities or symbols according to a set of rules. Connectionism: A form of computational modeling based on simulated networks of simple processing units akin to neurons. Neural impulse: A brief, discrete electrical signal (also known as action potential) that travels rapidly along a cell’s axon. (Zie voor de werking van zenuwen blz. 12/13.) Photoreceptor: A specialized nerve cell that produces electrical signals when struck by light. Mechanoreceptor: A specialized nerve cell that produces electrical signals when subjected to mechanical deformation. All of the senses except olfaction (they go directly from olfaction bulb to cortex), one of the synapses route from sense organ to brain (cortex) is located in the thalamus: A large dual-lobed mass of neurons lying in the middle of the brain at the top of the brainstem and below each cerebral cortex, which relays information to the cortex from diverse brain regions. Cortical receiving area: An area of the cortex where afferent (incoming) fibers from a sense organ terminate; als known as primary sensory cortex. Cortical association area: An area of the cortex that receives information from neurons in a cortical receiving area; also known as secondary sensory cortex. Each sensory system responds only to a particular range of stimuli, this can be described as the sensory space. Receptive field: The area of a stimulus field in which presentation of a stimulus causes a change in the firing rate of a given sensory neuron. Specific nerve energy: The idea that neural signals in the senses are differentiated by their pathways in the nervous system, rather than by differences in the nature of the signals themselves. The brain is able to tune itself into the changing sensory environment of the developing organism, though this plasticity is only possible for a limited period during development. Over much shorter time periods, each sensory system is also able to adapt itself to the specific sensory environment. Adaptability: The ability of a sensory system to vary its response characteristics to match prevailing stimulation. 2 Janneke Martens Noise: The variation in response to repeated presentation of identical stimuli. Two causes: 1. There are fluctuations in the electrical excitability of neurons, caused by random opening and closing of ion channels. 2. There are fluctuations in synaptic transmission caused by the random nature of diffusion and chemical reaction across synapses. Stimulation of the sense organ causes a conscious mental state, this causes sensations or qualia: Primitive mental states, such as sensory impressions induced by stimulation of a sense organ. Detectability: there must be a certain intensity before a stimuli evokes an sensory experience. In a graph called psychometric function: a graph relating stimulus value to the response rate of an experimental subject. (eg. Proportion of yes responses.) The intensity also affects the perceived magnitude (omvang, belangrijkheid) of a stimulus. Stevens’s power law: A nonlinear relationship between stimulus intensity and perceived magnitude, in which equal ratios of intensity produce equal ratios of magnitude. Iedere x licht intensiteit 6x zo groot, dan neemt de helderheid toe met een factor 2. Sensory system provide information about changes in the level of stimulation rather than about the absolute level of stimulation. Adaption see figure 1.16, page 20 it has 3 stages! Sensitivity changes, intensity of stimulus diminishes, sensitivity changes back. Representation: The idea that the state of one physical system can correspond to the state of another physical system; each state in one system has a corresponding stat in the other. The internal state of the brain represents the state of the outside world. • Analog representation: A representation in which values in one system, such as spatial position or response rate, vary proportionately with values in another system. Horloge of film ve vogel. • Symbolic representation: A representation in which discrete symbols such as characters or words in one system act as tokens for the state of another system. Digitaal Horloge, there is no continuous change, just gives the current time. Of beschrijving van een vogel. Both representations are ways some people see the representation of the outside world in the brain. Labeled line: A general principle of sensory processing, according to which a perceptual attribute or “label” is uniquely specified by activity in a restricted set of neurons. Computation: ? Linking proposition: A proposition positing a specific causal link between neural activity in the brain and perceptual experience. Lees ook de chapter summary op blz. 25/26. Chapter 2 Smell - Olfactory = reukzin Olfactory receptor neuron: A specialized neuron that produces electrical responses to odor molecules. Olfactory epithelium: A patch of mucous membrane in the roof of the nasal cavity (one for each nostril) containing olfactory receptor neurons; in humans it contains 6 million receptor neurons. Free nerve ending: A branch of a sensory nerve cell that has no specialized receptor process, but is embedded directly in tissue. Zie ook figuur 2.2 op blz. 44 Mitral cell: A neuron in the olfactory bulb that receives signals from olfactory receptor neurons and relays them to the brain; there are 50000 mitral cells in the human olfactory bulb. 3 Janneke Martens Olfactory bulb: The mass of neural tissue protruding from the brain behind the nose, which conveys neural signals from the olfactory epithelium tot the brain. Olfactory glomerulus: A dense, spherical accumulation of dendrites and synapses, where approximately 200 olfactory receptors make contact with a single mitral cell. Primary olfactory cortex: The cortical destination of mitral cell fibers, thought to mediate perception of smell. Amygdala: A nucleus (dense group of neurons) lying deep in the brain, forming part of the limbic system; involved in emotional, sexual and autonomic responses. The detection chance depends on the odor, which concentration is needed. Any recognition theory about odors must included linking proposition! Cross-adaption: An experimental technique in which subjects are adapted to one stimulus for a period of time before their response to a different stimulus is measured. Anosmia: Odor blindness; Lack of sensitivity to odor. Taste = gestation. The five taste qualities: sweet, sour, salty, bitter and umami. Taste receptor: A chemoreceptor cell found on taste buds in the mouth, tongue, and throat; there are 50-150 receptors on each bud. Taste bud: A cluster of cells embedded in the skin of the tongue and mouth, housing taste receptors. The human tongue contains approximately 5000 taste buds. Gustatory papilla: A small elevation on the tongue, visible to the naked eye, containing up to several hundred taste buds. Papillae: taste buds are located on small projections called papillae. Umami: A Japanese word meaning “good taste”; recent evidence indicates that it is a fifth basic taste quality. “yummy” (is related with amino acids building block for proteins.) Taste tetrahedron: A geometric representation of four basic sensory qualities of taste (sweet, salt, sour, bitter) using a three-sided pyramid. Taste primaries: A theory of taste coding based on the idea that perceived taste can be broken down into basic qualities, each uniquely associated with activity in a specific neural pathway. Cross-fiber theory: A theory of taste coding based on the idea that perceived taste is based on the pattern of activity across different classes of sensory fiber. Flavor is determined by an interaction between taste, smell, temperature, touch, sight, sound and pain. Chapter 3 Proprioception: The sensory modality providing information about the position of body parts, served by mechanoreceptors in the musculoskeletal system. Kinesthesis: The sensory modality providing information about the movement of body parts, served by mechanoreceptors in the musculoskeletal system. Somatosensory system: deals with touch, proprioception and kenesthesis. Tabel 3.1, blz. 62 8 receptoren en 2 paden to the primary receiving area in the cerebral cortex. Touch receptors: Mechanoreceptors and free nerve endings below the surface of the skin, mediating perception of pain, temperature, pressure, vibration and stretch. Nerve endings can be captured in: 1. Pacinian corpuscles: onion like capsule, stimulation vd membrane leads to a receptor response. Is connected to a RA or PC mechanoreceptor. 2. Merkel’s disks & Ruffini’s corpucscles: suited for noticing relatively stable, unchanging mechanical stimulation. They have a sluggish temporal response. Are connected to a SAI of SAII mechanoreceptor. 3. Meissner’s corpuscles: able to detect moderate dynamic stimulation, intermediate temporal response. Is connected to a RA or PC mechanoreceptor. (zie figuur 3.2) 4 Janneke Martens Proprioceptors: Mechanoreceptors in muscles, tendons, and joints mediating perception of body position and movement. (in & around the limbs) Dorsal root ganglia: Rounded swellings lying in the vertebrae just outside the spinal cord, each containing thousands of afferent cell bodies whose axons enter the spinal cord. Spinothalamic pathway: The ascending sensory pathway for pain and temperature signals from free nerve endings. Axons are lightly/or not myelinated 2 m/s. Lemniscal pathway: The ascending sensory pathway for somatosensory signals from mechanoreceptors. Axons are myelinated 20 m/s. Microneurography: A technique for recording human sensory nerve activity using needle electrodes inserted through the skin into a nerve trunk. Zie ook figuur 3.3 Both pathways do not only go to the thalamus & primary somatosensory cortex, but also a direct reflex route. (knee-jerk reflex) Primary somatosensory cortex: a long thin strip of cortical surface running from ear to ear across the head. Which is divided in to 3 Brodmann areas, area 3 is the most active by somatosensory. Each cell is connected to one type of receptor. Figuur 3.4 Lateral inhibition: Inhibition that travels across a neural network to impede the forward flow of activity. Center-surround receptive field: A receptive field containing concentrically organized regions of excitation and inhibition, as a result of lateral inhibition. Cortical column: A group of cells lying within a block extending perpendicular to the surface of the cortex that share a common response property, such as receptive field location or stimulus preference. Channel: A specific route through a processing system, usually carrying a specific kind of information. Haptic perception: The perception of shape, size and identity on the basis of touch and kinesthesis (the ability to feel movement of the limbs and body). Ventral: Brain regions toward the front and lower part of the brain, such as the temporal lobe. Dorsal: Brain regions toward the back and upper part of the brain, such as the parietal lobe. Vestibular system: deals with balance. Vestibular organ(s): A fluid-filled organ lying in a deep cavity on the side of the skull (one on each side); it provides information about the orientation and movement of the body relative to the external environment. See figure 3.7, page 73. Vestibular receptor(s): A mechanoreceptor that produces an electrical response when hair-like protrusions are deflected as a result of external forces. FIGURE 3.8; page 74. Kinocilium: The single, tall, hair-like structure projecting from each vestibular receptor. Stereocillia: The small, hair-like structures projecting from each vestibular receptor to one side of its kinocilium; they are connected to the kinocilium by fine filaments. The hair-like structures above don’t work with an action potential, but with active zones which make synaptic connections with afferent nerve cells forming part of the VIII cranial nerve. Vestibular labyrinth consist of two chambers and three semicircular canals. Otilith organs: two fluid-filled sacs, the utricle and saccule, in each vestibular organ Macula: The patch of vestibular receptors in each otolith organ. Static info about gravitational vertical acceleration & dynamic info about linear acceleration. Semicircular canals: Three ring-shaped canals in each vestibular organ, arranged at right angles to each other. Crista: The patch of vestibular receptors in each semicircular canal. Head movement: 3 planes (median, frontal, transverse); 3 axis (x,y,x); rotation around x,y,z called respectively roll, pitch and yaw. 6 degrees of freedom. 5 Janneke Martens Vestibular nuclei: Groups of nerve cells in the brainstem that receive axons from the vestibular receptors; they also receive inputs from the cerebellum, visual system, and somatosensory system. His projections can be grouped in four systems: (figure 3.11; page 79!!) 1. The vestibule-cerebellar system: controls posture and bodily equilibrium 2. The vestibule-thalamic system: mediate perception and balance 3. The vestibule-spinal system: a. Medial tract: reflexive control of body posture and head b. lateral tracts: limb movements to maintain balance. 4. The vestibule-ocular system: control eye movements Vestibulo-oclur reflex: The reflexive eye movements that compensate for head and body movement to stabilize the visual image on the retinas. Vertigo: distorted perception of observer orientation relative to gravitational vertical, or motion relative to the environment. Oculogyral illusion: Visual disorientation and apparent movement following rapid body spins. Coriolis effect: The apparent deflection of the head experienced when it is moved during a body spin. Oculogravic illusion: The apparent backward head tilt and visual elevation experienced during forward body acceleraton. Vection: The illusion of body motion caused by visual stimulation. Phantom limb: The illusion that an amputated extremity such as a finger, leg, or penis is still present. Chapter 4 Sine wave: A wave whose height varies smoothly so that it conforms to a mathematical sine function of time or distance (adjective: sinusoidal). The sinusoidal variation in sound pressure level has three important features: 1. Frequency: The number of cycles (periods) of a wave per unit of time or distance. Variation in frequency relates perceptually to variation in perceived pitch (toonhoogte). Low frequency ↔ deep bass pitch. 2. Amplitude: The maximum height of a wave, measured from its mean value to its maximum value. Corresponding to the amount of change in pressure. Expressed in decibel (dB): A measure of the difference between two quantities, based on the logarithm of their ratio (so equal ratios between the quantities correspond to equal dB differences). a. The dB scale is relative. Sound pressure level (SPL): A decibel measure of sound pressure relative to a fixed reference pressure. (0.0002 dynes/cm2; 1000 Hz) b. The dB scale is logarithmic 3. Phase: A measure of the timing or position of a wave relative to a fixed point of reference, or to another wave. Complex wave: A wave that can be decomposed into a collection of simple, sinusoidal waves. Fundamental frequency: The lowest sinusoidal frequency that is an integer multiple of the fundamental frequency. relates to its perceived pitch. Harmonic frequency: A sinusoidal component of a complex wave, having a frequency that is an integer multiple of the fundamental frequency. 6 Janneke Martens Most natural sounds are not periodic and contain a continuous “spectrum” of complex waves. With the Fourier theory you can break down all complex sounds into sine waves. Fourier analysis: The mathematical procedure by which a complex signal is decomposed into its magnitude spectrum and phase spectrum. Fourier spectrum: A representation of the magnitude of individual frequency components present in a signal such as a sound wave; it is also known as the magnitude spectrum. Fourier synthesis: recombines the components so that the original signal can be reconstituted. Phase spectrum: A representation of the relative phases of individual frequency components present in a signal. Spectrogram: A graphical representation of changes in the frequency content of a signal over time. Frequency filter: Any process that modifies the frequency content of signals passing through it. Transfer function: A function that describes a linear filter’s frequency response, in terms of the degree of attenuation at each frequency. To adjust a Fourier analyze to a filter, the filter must (assumed to) be linear. Linear filter: A frequency filter that modifies the amplitude of input frequency components that were not present in the input. 3 rules: (linear system theory) 1. The output never contains any frequency that wasn’t in the input signal. 2. If the input amplitude is changed by a factor, the output must also change by the same factor. 3. If a number of sine wave inputs are simultaneously applied, then the resulting output should match the output of the sum of the output of the individual sine waves. Nonlinear filter: A frequency filter that distorts signals by adding new frequencies or by failing to respond at very low or high amplitudes. Zie figuur 4.11!! Belangrijk het oor! Outer ear: The outermost components of the auditory system: the pinna, meatus and ear canal. Ear canal: The S-shaped tube leading from the meatus to the tympanic membrane; it is approximately 0.6 cm wide and 2.5 cm long. Meatus: The opening into the ear canal. Tympanic membrane: The flexible cone-shaped membrane extending across the inner end of the ear canal; it transmits sound energy to the middle ear. Via three bones (ossicles) this membrane passes the vibrations trough to the cochlea. Pinna: The external ear visible on each side of the head; its shell-like inner part (concha) funnels sound into the meatus. Middle ear: The aer-filled cavity containing the bones (ossicles) and associated supporting structures that transfer sound energy from the outer ear to the inner ear. Oval window: The point of entry for sound energy into the inner ear; it is a small membrane-covered opening in the cochlea. Impedance: The degree of resistance offered by a medium to an oscillating signal. (Air and liquid in the ear, therefore there are the ossicles.) Complex signal Fourier analysis Fourier synthesis Fourier spectrum 7 Janneke Martens Impedance matching: The boost in pressure at the oval window (between middle ear and cochlea) provided by the mechanical properties of the middle ear, it matches up the differing acoustic impedances of air and inner ear fluid. Inner ear: The fluid-filled organ lying in the temporal bone, containing mechanoreceptors for hearing and balance. Cochlea: The spiral-shaped structure in the inner ear containing mechanoreceptors for hearing. Scala vestibule: The tube running along the cochlea that contains the oval window at its base. Scala tympani: The tube running along the cochlea that contains the round window at its base. Cochlear partition: The flexible structure separating the scala vestibule and the scala tympani. Houses the basilar membrane: The flexible structure on the cochlear partition that houses mechanoreceptors; it forms part of the organ of Corti. Traveling wave: The ripple of displacement that travels along the basilar membrane when sound vibrations are applied to the oval window. Frequency-to-place conversion: The fact that the place of maximum displacement on the basilar membrane depends on the frequency of sound vibration. Organ of Corti: The complex structure that forms part of the cochlear partition; it contains mechanoreceptors sandwiched between two flexible membranes. Tectorial membrane: The flexible structure lying on top of the basilar membrane. Inner hair cells: The mechanoreceptors on the basilar membrane that provides afferent signals to the auditory system when the membrane is displaced. Most sensory info about sound is from them. Outer hair cells: Motile hair cells spanning the gap between the basilar membrane and tectorial membrane; they control the mechanical coupling between the two membranes. Able to change size, expanding and contracting. They contain proteins supporting muscle-like contractions and receive efferent stimulation from the cochlea nerve. Oto-acoustic emission: A sound emitted from the ear, either spontaneously of following auditory stimulation. Phase locking: The firing of hair cells in synchrony with the variation of pressure in a sound wave. (fig. 4.17, blz. 109) Neurons cannot fire more than once/ms, because that is the refractory period. So they have two methods for sound encoding: 1. Place code: 2. Frequency code: Dynamic range: In auditory nerve fibers, it is the difference between the minimum SPL to which a fiber responds, ant the SPL at the fiber’s maximum firing rate. Two-tone suppression: Suppression of an auditory nerve fiber’s response to a tone during presentation of a second tone. The ear is not a Fourier analyzer but can be viewed as an approximation to Fourier analysis. Cochlear nucleus: The mass of nerve cells in the brainstem where auditory nerve fibers terminate. Superior olive: The complex of cells in the brainstem receiving projections from the cochlear nucleus; it contains binaural neurons that provide information about the location of sound sources. Medial geniculate nucleus: The obligatory relay station for all ascending projections in the auditory system, en route to the cortex. Fig. 4.20, blz. 113; schematische weergave vd auditory pathways. Azimuth: Direction in the horizontal plane, relative to straight ahead. Interaural time difference (ITD): A difference in the time of arrival of an auditory stimulus at one ear relative to the other. Interaural level difference (ILD): A difference in the intensity of an auditory stimulus arriving at the one ear relative to the other. Primary auditory cortex: The cortical destination of projections from the medial geniculate nucleus. 8 Janneke Martens Tonotopic organization: An organized arrangement of neurons, so that cells with similar frequency preferences lie close together in a neural structure. Auditory association cortex: Two concentric bands of cortex encircling primary auditory cortex, containing cells responsive to auditory stimuli. Even function: A function that is symmetrical with respect to the y-axis, so the value of y at x is equal tot the value of y at –x; the function y = cos (x) is even. Odd function: A function that is asymmetrical with respect to the y-axis, so the value of y at x is nog equal to y at –x; the function y = sin (x) is odd. Inner product: A number whose value represents the degree of correspondence between two functions. Complex waves: A number having two parts, called real and imaginary, from which other numbers can be computed; in Fourier analysis the parts represent the cosine and sine contributions to each component. Magnitude: The strength of the contribution of a given frequency component in a waveform; it is calculated from the complex number for each component. Phase: The relative position of a given frequency component in a waveform; it is calculated from the complex number for each component. Fourier series: A discrete series of frequency components making up a periodic (repetitive) waveform. Fourier integral: A continuous spectrum of frequency components making up a nonperiodic (nonrepeating) waveform. Euler’s relation: A mathematical rule that allows a sine and cosine pair to be represented as an exponential. Fast Fourier transform (FFT): A numerical computational technique for performing Fourier analysis on an array of signal values. Chapter 5 Loudness: The perceptual attribute of a sound that relates to its intensity. (SPL) Loudness matching: adjust the intensity of a sound equal to the comparison stimulus. Equal-loudness contour: A curve plotting the SPLs of sounds at different frequencies that produce a loudness match with a reference sound at a fixed frequency and SPL. (figuur 5.2, blz. 130) Loudness scaling: In de les gedaan, 1 geluid = 100% hoeveel % geluid 2. Excitation pattern model: A theory of loudness perception in which the loudness of a sound is proportional to the summed neural activity it evokes in the auditory nerve. One possible limitation to compare loudness is memory, it requires the listener to retain a memory trace. Decay of the trace may inject ‘memory noise’. Pitch: The perceptual attribute of a sound that relates to its frequency. It allows us to order sounds from low bass to high treble notes. Pure tone: pitch is related to the frequency of the tone Complex tone: pitch is related to the frequency of the fundamental. Frequency selectivity: Masking: An experimental effect in which a subject’s ability to detect a sound signal is impaired in the presence of noise. Band-pass noise: A sound stimulus containing equal energy within a certain band of frequencies above and below its center frequency. Critical bandwidth: ? Figuur 5.4, blz. 134 9 Janneke Martens Critical-band masking: An experimental effect in which masking of a sinusoidal signal occurs only when the center frequency of the noise falls within a certain band of frequencies surrounding the signal. The presence of the signal increases the level of activity in auditory filters tuned to its frequency. When this response increment exceeds some minimum value, the signal is detected by the listener. The mask also produces excitation in auditory filters, but this activity is obviously unrelated to the presence of absence of a signal Frequency discrimination: measures a listener’s ability to detect small changes in freq. Theories of pitch perception: relation between neural activity and perceived pitch Pure tones Place theory: A theory according to which pitch is determined by the place of maximum excitation on the basilar membrane; frequency-to-place conversion of the basilar membrane. Timing theory: A theory according to which pitch is determined by the timing of neural impulses in the auditory nerve; timing of responses in auditory nerve fibers. Complex tones; missing fundamental wave: A complex wave from which the fundamental frequency has been removed. Temporal theory: the pitch of a complex sound is encoded in responses synchronized to its beat frequency. Beat: Regular changes in the amplitude of a wave when two or more sine waves at different frequencies are added together. Residue pitch: The pitch heard in a complex wave as a result of beats rather than resolvable harmonic components. (unresolved harmonics) Pattern recognition theory: A theory of pitch perception in complex sounds, according to which pitch is determined by the harmonic series that best fits the pattern of frequencies in a sound. (resolved harmonics) Autocorrelation theory: comparing a signal with a delayed representation of itself. Elevation: The direction of a sound source in the vertical (up-down) plane. (azimuth is horizontal) Horizontal localization relies on binaural cues (comparisons between the signals arriving at the two ears) Minimum audible angle (MAA): The smallest change in the azimuth angle of a sound source that can be detected reliably. (figure 5.7; page 140) Duplex theory: A theory of auditory localization in which low frequency sounds are localized using interaural time differences, and high frequency sounds are localized using interaural intensity differences. ILD: interaural level differences; het ene oor ligt in de ‘schaduw’ van de andere. Intensity in the further ear is lower. ITD: interaural time differences; sound arrives slightly later in the further ear. Cone of confusion: A cone of space extended from a listener’s head, defining the directions that produce the same interaural time difference and are therefore confusable. Vertical localization relies on monaural cues (information available in the signal arriving at just one ear). Precedence effect: A phenomenon in which apparent sound source direction is determined by the earliest sound to arrive at the ear. Distance judgements: sound intensity provides a simple cue to distance, louder = closer; direct-toreverberant energy ratio ( direct or indirect sound waves); distance alters the spectrum of sounds, sounds of more distant sources appear muffled; distances closer than 1m ILD increases substantially as distance declines. 10 Janneke Martens Formant frequencies: The distinctive frequency at which the vocal tract (the tube of air between the larynx and lips) vibrates to create a certain vowel sound. Formant transitions: formants display a smooth change in their frequency during 50 ms. Speech mode: A mode of auditory processing that is specialized for processing speech sounds. Categorical perception: Each stimulus is perceived as a member of a discrete category, in an all-ornothing fashion, rather than as a value along a continuous dimension. (supported by speech processing) Phoneme boundary: A formant frequency defining the boundary at which perception switches from one honeme to another. Wernicke’s area: An area in the left hemisphere of the human cortex where damage results in disordered speech perception (Wernicke’s aphanis). Auditory streaming: Grouping of parts of a complex acoustic signal into discrete auditory objects. Sequential grouping: the auditory system assigns successively occurring sounds to specific auditory streams. Simultaneous grouping: the auditory system assigns simultaneously occurring sounds to specific auditory streams. Also see figure 5.13; page 150. Conductive hearing loss: Deafness caused by impaired conduction of sound energy by the outer and middle ear. Sensorineural hearing loss: Deafness caused by damage to the inner ear, especially cochlear hair cells. Loudness recruitment: Abnormally rapid growth in loudness with SPL, resulting from damage to outer hair cells in the coclea. Prebyacusis: Age-related hearing loss associated with deterioration of the cochlea. Chapter 6 Refrection: The change in the direction of a light ray as it passes from one transmitting medium to another, caused by a change in the velocity of propagation. Interface: The pattern formed when two sets of waves overlap, producing mutual reinforcement at some locations and cancelation at others. Diffracton: Scattering or bending of a wave as it passes around an obstacle or through a narrow opening. Light (by Maxwell): An electromagnetic disturbance in the form of waves. Electromagnetic spectrum: The full range of frequencies that characterizes electromagnetic radiation; only a tiny portion of it is visible as light. Quantum (by Planck): The smallest discrete unit of energy in which radiation may be emitted or absorbed. (E=hf; h= 6.63 x10-34) Photoelectric effect (by Lenard): electrons can be released from a metal surface when it is struck by light. Intensity ↔ # electrons; Frequancy ↔ Ekin. How can light be a particle and a wave? 1. Ray properties are especially useful when attempting to understand howimages are fromed by optical devices such as eyes. 2. Wave properties are important when considering the behavior of light at a much fine scale, such as when dealing with passage through small apertures (pupil) or along very narrow waveguides (photoreceptors) 3. The quantal nature of light intrudes on visual perception when light intensity is so low that quantum absorptions can be counted individually. Absorption: light quanta (photons) are converted into thermal energy. Reflection: light rays are scattered backward at the interface. (Specular & diffuse; fig. 6.4; page 164) 11 Janneke Martens Transmission: quanta of certain wavelengths may be scattered by molecules they hit. Results in retardation (vertraging), which has consequences Refraction: a change in direction. Occurs in 4 surfaces at the eye: Anterior (front) corneal surface, Posterior (back) corneal surface, front surface of the lens & rear surface of the lens. Refractive index: The ratio of the velocity of propagation of an electromagnetic wave in a vacuum to its velocity in a given transmitting medium. Focus length: The distance from the center of a lens to its focal plane (the plane in which parallel light rays are brought into sharp focus). Radiometry: The measurement of electromagnetic radiation. To measure light intensity (#quanta emits per unit of time) Photometry: The measurement of visible electromagnetic radiation. To measure light intensity (vision; cd/m2) Luminance: A photometric measure of the energy emitted or reflected by an extended light source, in candelas per square meter of surface (cd/m2). (table 6.1; page 166) Reflectance: The proportion of incident light reflected from a surface. Contrast: A measure of the difference between the highest luminance and the lowest luminance emitted or reflected from surface. = ( − )⁄( + ) Spectral reflectance function: The proportion of light reflected from a surface as a function of the wavelength of the incident light. Eye figure 6.8; page 170 Cornea: The transparent membrane through which light enters a single-chambered eye. Pupil: The circular aperture formed by a muscular diaphragm in the eye, through which light passes after entering the cornea. Vitreous humor: a viscous gel that fills the large posterior chamber of the eye, maintaining its shape and holding the retina against the inner wall. Aqueous humor: watery. Pumped into the eye continuously, entering the eye near the attachment of the lens and leaving near the margins of the iris. Flows in both chambers. Visual angle: The angle an object subtends at the center of a lens; it is used to measure the size of an object as a stimulus for vision. tan = ⁄ Diopter: A measure of the fefractive power of a lens; it corresponds to (1/f) where f is its focal length in meters. Accomodation: The process by which the shape of the eye’s lens is changed to alter its focal length. Presbyopia: The age-related change in accommodative range, resulting from loss of flexibility in the lens. Myopia: A condition in which the refractive power of the eye’s lens is too great, causing the image of distant objects to be defocused. Hyperopia: A condition in which the refractive power of the eye’s lens is too weak, causing the image of near objects to be defocused. Pupil size is influenced by emotional responses. Photoreceptor: long, thin tube; outer segment light sensitive pigment; inner segment forms cell body. Rod: A type of photoreceptor that is specialized for responses at low light levels. Cone: A type of photoreceptor that is specializedfor responses at high light levels. Resolution: the ability to resolve fine spatial detail in the retinal image Grating: A pattern of alternating light and dark bars, widely used in vision research. Magnification: The size of the image produced by a lens; it depends on the focal length of the lens. 12 Janneke Martens Interreceptor angle: The visual angle between tow neighboring photoreceptors; it determines the resolving power of the eye. Sensitivity: the ability to respond at very low illumination levels. Photon noise: The inherent natural variation in the rate at which photons strike a receiving surface such as the retina. Chromatic aberration: The property of an optical system that causes light rays at different wavelengths to be focused in different planes, so degrading the image. Sphericla aberration: The failure of light rays striking all parts of a lens to converge in the same focal plane, so degrading the image. There are six extraocular muscles, figure 6.13; page 179. The eyes can move conjugate (2 eyes, same direction & amount) or disjunctive (2 eyes, same amount & opposite direction). Table 6.2, page 180 Saccade: The rapid, jerky eye movement used to shift gaze direction Motion blur: Smearing in an image caused by movement of an object relative to the imaging surface. Airy disk: The image of a point light source created by an optical system; it contains a bright central spot surrounded by several faint rings. Linespread function: The image (or a mathematical function describing the image) of a very thin line created by an optical system. Photopic vision: Vision at high illumination levels (above approximately 4cd/m2), mediated by cone photoreceptors. Scoptic vision: Vision at low illumination levels (below approximately 1cd/m2), mediated by rod photoreceptors. Troland: A photometric unit specifying retinal illuminance, which takes into account pupil diameter. Stiles-Crawford effect: The variation in the sensitivity of the retina with the place of entry of light rays at the pupil. Chapter 7 (blz 206) Visual system, figure 7.1; page 197 Retina: neural circuitry connecting photoreceptors to the ganglion cells, whose fibers form the optic nerve. Photoreceptor cells: Elight neural signals Ganglion cell fibers: carry neural signals towards the brain Retinal circuity of the inner nuclear layer: connects photoreceptors to ganglion cells. Visual pathway: the optic nerve, the cell nuclei to which its fibers project, and the onward projection tot the cortex. Visual cortex: all cortical areas that contain cells responsive to visual stimuli. Outer nuclear layer Photoreceptor components: zie figuur 7.3; page 199 Photon absorption: direction & frequency Photoreceptor responses: Photoisomerization; graded potentials; fig 7.4; page 200 Univariance: when a photon is absorbed, its effect on a photoreceptor is the same regardless of the photon’s wavelength. Inner nuclear layer Bipolar cell: transmit responses vertically from photoreceptors towards ganglion cells. Tab. 7.1 On bipolars are activated by an increase in the photon catch of receptors. Depolarize. Off bipolars are activated by a decrease in the photon catch of receptors. Hyperpolarize. Cone bipolar: A class of retinal cell that conveys activity from cone photoreceptors to ganglion cells. 13 Janneke Martens Rod bipolar: A class of retinal cell that conveys activity from rod photoreceptors to amacrine cells. These make connection to cone bipolar cells. Horizontal cell: a class of retinal cell whose axons spread laterally across the retina, making contact with several photoreceptors. Lateral inhibition: stimulation of horizontal cells by photoreceptors is fed back to reduce the influence of the photoreceptors on bipolar cells. Amacrine cell: a class of retinal cell that has extensive contacts with bipolar cells, ganglion cells, and other amacrine cells; it serves a number of functions. The AII amacrines convey rod signals to cone bipolars. Ganglion cell: the class of retinal cell that provides the output signal from the retina; ganglion cell axons form the optic nerve. Tabel 7.2/figure 7.6; page 204.205. Biplexiform ganglion cell: a class of ganglion cell that connects directly to photoreceptors. Bistratified ganglion cell: The least numerous ganglion cell class; it responds only at high light levels, has no spatial opponency, but shows blue-yellow spectral opponency. Midget ganglion cell: The most numerous class of ganglion cell; it responds only at high light levels, shows spatial opponency,and may also show red-green spectral opponency. Parasol ganglion cell: The only class of ganglion cell that remains active at low light levels; it shows spatial opponency but does not chow spectral opponency. Spatial opponency: Excitory responses generated in one part of the retinal receptive field are opposed by inhibitory responses in another part. Spectral opponency: Wavlengths from one portion of the spectrum excite a response, and wavelengths from anointer portion inhibit a response. Sustained temporal response: A change in response is sustained at a relatively high level for the whole duration of stimulation. Transient temporal response: A change in response occurs only at the onset and offset of stimulation. Neural blur: The removal of spatial detail in neural responses, as a result of neural processes rather than optical effects. Chromatic channel: A channel of processing in the visual system that conveys information about the chromatic of colour properties of the image. Achromatic channel: A channel of processing in the visual system that conveys information about the luminance or light-dark properties of the image. Lateral geniculate nucleus (LGN): The mass of neurons in the thalamus where optic nerve fibers from the retina terminate. Magno layers: layers in the lgn with large cell bodies; they receive projections from parasol ganglion cells. Parvo layers: layers in the lgn with small cell bodies; they receive projections from midget ganglion cells. Konio layers: sublayers of lgn magno and parvo layers that contain the smallest cell bodies; they receive projections from bistratified ganglion cells. Binocular neuron: a neuron that has a receptive field in each eye. Partial decussation: partial crossover of each eye’s optic nerve fibers in the visual pathway, so that half stay on the same side of the brain, and half cross over. Striate cortex: the primary receiving area for visual signals from the lgn; it is also known as V1 or area 17 Extrastriate cortex: areas of secondary visual cortex that receive signals from striate cortex. Simple cell: an orientation selective cell in visual cortex with an elongated retinal receptive field containing excitatory and inhibitory zones. 14 Janneke Martens Complex cell: a cell in visual cortex with a relatively large receptive field that does not contain identifiable excitatory or inhibitory zones, but nonetheless is orientation selective. Direction-selective cell: a visual cell that responds more strongly to retinal movement in one direction that to movement in the opposite direction. Ocular dominance: a property of binocular cortical cells, describing their tendency to respond more strongly to stimulation in one eye than to stimulation in the other eye. Binocular disparity: a small difference between images in the two eyes that provides a cue to depth, usually created by viewing a scene containing objects at different depths. Double opponency: a property of an antagonistic enter-surround receptive field, in which certain wavelengths evoke excitation in the center and inhibition in the surround; v.v. for other wavelengths. Ocular dominance column: A slab of cortical tissue running perpendicular to the cortical surface, in which all binocular cells share the same degree of ocular dominance. Orientagion column: a slab of cortical tissue running perpendicular to the cortical surface, in which all orientation selective cells share the same preferred orientation. Blob: a cluster of cells in the superficial layers of striate cortex identified by a staining technique, many of which are color selective. Hypercolumn: a block of cortex containing one complete cycle of ecular dominance and a full range of orientation preferences. Response latency: the time elapsed between the onset of a visual stimulus and the onset of response in a given neuron. Stripes: groups of cells in area V2 of visual cortex identified by a staining technique. Processing stream: a series of neural processing stages in a sensory system specializing in the extraction of certain stimulus attributes. Dorsal stream: a processing stream including cortical areas V3, MT, and MST, which is claimed to specialize in the analysis of movement, depth, and action. Ventral stream: a processing stream including cortical areas V4 and IT, which is claimed to specialize in the analysis of spatial form. Information processing device: a “black box” description of a physical system in terms of an input signal, an output signal and an intervening process that converts one into the other. Difference-of-gaussians (DoG): a mathematical description of a receptive field profile as the difference between two Gaussian or normal distributions; one is excitatory and the other is inhibitory. Space constant: the parameter specifying the width of a Gaussian or normal distribution; mathematically it corresponds to the stander deviation of the distribution. Convolution: a mathematical procedure used to combine a receptive field profile with a stimulus profile, in order to model the response of the receptive field. Chapter 8 Scotopic vision: Vision at the low ambient light levels typical of nighttime, mediated by rods. Photopic vision: Vision at the high ambient light levels typical of daylight, mediated by cone photoreceptors. table 8.1, page 237. Mesopic vision: Vision at ambient light levels intermediate between photopic and scotopic levels, typical of dusk, mediated by both rods and cones. Purkinje shift: the shift in brightness in scotopic and photopic of a wavelength near 507 nm. Luminance grating: a laboratory stimulus used to study spatial vision(detected of spatial features in the image); it is a striped pattern containing alternating light and dark bars, commonly with a sine wave luminance profile. Page 239 figure 8.2 Contrast: the intensity difference between the lightest & darkest part of the luminance peak. 15 Janneke Martens Spatial frequency: a measure of the fineness of a grating’s bars, in terms of the number of grating cycles (bright-dark bar pairs) per degree of visual angle. Orientation: the slant of the grating’s bars. (the angle) Phase: the position of the bars with respect to some fixed point on a display. Spatial contrast threshold: the minimum contrast between the lightest and darkest parts of a pattern required for it to be reliably detected by an observer; lower values indicate better performance. Spatial contrast sensitivity: the reciprocal of spatial contrast threshold (1/threshold); higher values indicate better performance. Contrast sensitivity function (CSF): a graph of spatial contrast sensitivity to luminance gratings, plotting sensitivity as a function of grating spatial frequency. figure 8.3; page 241 Contrast ratio: the ratio between the amount of contrast in an optical image, and the contrast in the original stimulus; values near unity indicate near-perfect transference. Optical transfer function (OTF): a graph of an optical system’s ability to transfer luminance gratings, plotting contrast ratio as a function of grating spatial frequency. Temporal contrast sensitivity: the reciprocal of the amount of contrast between the brightest and darkest phases of a flickering stimulus required for a subject to detect the flicker. Temporal frequency: the alternation rate of a flickering stimulus, measured in hertz, of the number of flicker cycles (bright-dark alternations) per second. Temporal contrast sensitivity function: a graph of temporal contrast sensitivity, plotting sensitivity as a function of flicker temporal frequency. Figure 8.7, page 244. Spatiotemporal contrast sensitivity: sensitivity to combinations of spatial modulation and temporal modulation, namely luminance grating with flickering bars. Space-time plot: a plot that represents luminance variation over both space and time, with space plotted horizontally and time plotted vertically. Spatiotemporal CSF: a graph of spatiotemporal contrast sensitivity, plotting sensitivity as a function of grating spatial frequency and temporal frequency. Sustained channel: a channel of processing in the visual system that is most sensitive at high spatial frequencies and low temporal frequencies. Transient channel: a channel of processing in the visual system that is most sensitive at low spatial frequencies and high temporal frequencies. Spatial scale: coarse scale general shape & structure; fine scale details about sharp edges ed Can be compared with the fourier theory Spatial filtering: you filter out or the high or the low frequencies (fig. 8.11 page 250) Figure 8.12 page 251 Adaption: 3 stages (pre-, adaption, post-) fig. 8.13 page 254 Threshold measurement Threshold elevation: the contrast threshold for a test stimulus is higher following exposure to an adapting stimulus than before adaptation. Suprathreshold measurements Size after-effect: a change in the apparent spatial frequency of a test grating following exposure to an adapting grating. Tilt after-effect: a change in the apparent tilt of a tst stimulus following exposure to an adapting stimulus. Masking: a rise in the contrast threshold for a test stimulus in the presence of a second, masking stimulus. • Edge localization: to establish the shape en position of objects. Vernier acuity: an observer’s acuity for detecting the direction of small spatial offsets between collinear lines of edges; hyperacuity: acuity performance in which the observer can detect changes in spatial location that are smaller than te distance between adjacent retinal photoreceptors. 8.18 259 16 Janneke Martens Zero-crossing: a point where the value of a function such as a receptive field response changes from positive to negative. o Feature extraction; peak: a point where the value of a function such as a receptive field response reaches its maximum. o Feature map; primal sketch: a relatively primitive representation of local spatial structure in an image, produced by the initial stages of visual processing. Texture analysis; Visual texture: repetitive variation in properties such as local luminance, contrast, size, and/or orientation to create an extended pattern; Filter-rectify-filter (FRF): a sequence of image processing operations thought to mediate texture analysis; its output discriminates between image regions differing in visual texture. Figure 8.20 page 262. o Spatial filtering o Nonlinear transform o Second-stage spatial filtering o Feature extraction o • Chapter 12 Hue: the color itself; Saturation: the purity of the color(#wit); Brightness: perceived intensity of the light. Perceptual color space: a graphical representation of the hue, saturation, and brightness dimensions of color. Figure 12.1 page 360. Substractive color mixture: a color mixture created by combining dyes or pigments, which act to remove certain wavelengths from incident light. Additive mixture: a color mixture created by adding together different light wavelengths. Metameric colors: two colors that appear the same hue but emit or reflect physically different light wavelengths. Linearity & trichromacy are the laws which additive color mixture obeys. CIE chromaticity diagram: a standard graphical representation of the hue and saturation attributes of color, based on color matching data obtained from large groups of observers. Fig. 12.6 page 364 Complementary colors: colors that cancel each other out when mixed together, producing neutral white or gray. Chromaticity coordinates: the xy coordinates of a color in the CIE chromaticity diagram. Trichromacy theory: the theory that human color vision involves three primary color sensations. Chromatic channel: a channel of processing in the visual system that conveys information about the chromatic or color properties of the image. (red-green & blue-yellow) cardinal directions Achromatic channel: a channel of processing in the visual system that conveys information about the luminance or light-dark properties of the image. (light-dark) brightness Color interaction: a change in the apparent hue, saturation, or brightness of a colored surface in the presence of, or following exposure to, an inducing color. Simultaneous color contrast & color adaption Color constancy: the apparent hue of a reflective surface remains constant even when changes in the spectral power distribution of the illuminant alter the wavelengths reflected from it. Color deficiency: a reduced capacity to discriminate between colors, caused by an abnormality in cone photopigments. Anamalous trichromacy: a form of color deficiency in shich the individual possesses there different cone classes, but their spectral sensitivity is shifted relative to normal trichromats. Dichromacy: a form of color deficiency in which the individual possesses only two cone classes. 17 Janneke Martens Monochromacy: a form of color deficiency in which the individual possesses very few or no cones, and is therefore unable to discriminate between colors. Pseudo-isochromatic plate: a pattern of colored dots, used in the diagnosis of color deficiency; the shape seen in the dots varies according to the observer’s color vision. Chapter 9 – extra stof in de sheets Agnosia: a clinical condition characterized by disordered visual perception of shapes and/or objects. Apperceptive: deficient shape representation (matching a circle with a triangle) Associative: cannot identify objects from their images Gestalt laws: Proximity: 2 nearby points in the image are likely to originate from the same object than two points that are far apart. Similarity: group local image regions together if they contain similar visual texture. (size, color) Common fate: if different image regions contain movement that has a common direction and velocity, they are likely to have originated from the same object. Good continuation: ? Primitive: a symbolic description of a local image feature such as an edge or bar segment. Collector unit: a higher order neuron in the visual cortex activated by extended contours in the image. Parsing: a process that divides input signals into discrete, meaningful units. Generic viewpoint: a viewpoint providing a perspective on an object that is typical of many other viewpoints. Accidental viewpoint: a viewpoint providing a highly unusual, perhaps unique, perspective on an object. Crowding: word are legible when fixating on them, words short to left/right are not. The letters crowed each other out. Object identification intrinsic (shape, surface) and extrinsic factors. View-independent representation: an object representation that reflects only the intrinsic structure of the object; also known as an object-centered representation. Structural description: a view-independent representation containing a description of an object’s parts, and the relationship between the parts. Generalized cone: basic descriptor for all object parts. Figure 9.9 page 285. Geons: a limited set of basic geometric shapes. Figure 9.10/11 page 285/286. View-dependent representation: an object representation that reflects the structure of the object as seen from a specific viewpoint; also known as a viewer centered representation. Alignment: an intermediate view that matches a novel view. Figure 9.12 page 287 Feature space: a space in which each dimension represents the range of variation possible in a particular object property, such as size; each object occupies a unique location in the space. Chapter 10 – extra stof in de sheets Metric depth cue: a quantitative depth cue, in which cue value varies continuously and proportionately with distance. (Relative cues; object A vs. object B) Ordinal depth cue: a depth cue in which cue value varies in discrete ordinal steps, such as “nearer” versus “further”. (Absolute cues) Monocular depth cue: a depth cue available when only one eye is used; it is also available using two eyes. 18 Janneke Martens Retinal image size: an object of fixed size will project a smaller image onto the retina as it is seen from a more distant viewpoint. Figure 10.2/3 page 298 Height in the visual field (HVF): a monocular depth cue based on the vertical position of a point in the visual field; higher positions correspond to further distances. Figure 10.4 page 299 Texture gradient: a monocular cue to the orientation and depth of a textured surface; it is based on graded variation in the size, shape, and density of texture elements. Perspective gradient: element width or separation Compression gradient: element height in the direction of slant. Density gradient: the number of elements per unit of area in the image varies. Power law: a mathematical law describing the relationship between two variables. Image blur: point of focus is sharp, how further away from it, it becomes less and less sharp. Depth of field: the range of distances either side of the point of focus within which there is no perceptible blur in the visual image. Atmospheric perspective: Contrast of nearby objects is higher, than for those further away. Accommodation: is nonvisual. The lens of the eye must change shape when fixating on another point. Motion parallax: width variation. Movement in one part of an image relative to another, as can be produced by objects moving at different distances from the observer. (trein: zon & cactus) Optic flow: height variation. Figure 10.9 page 306 Shadow: cast shadows (shadow from on object that fall on another object’s surface) and attached shadows (shadows from the object on its own surface). Interposition: a monocular depth cue based on partial occlusion of a far object by a near object. Binocular depth cues: a depth cue available only when both eyes are used together. Vergence: is nonvisual. Both eyes move at the same time in the opposite direction; the visual axes must converge to project an image of the point onto the fovea in each eye. Vergence angle: the angle at which the visual axes of the two eyes intersect while the observer fixates on a point binocular; it offers a cue to fixation distance. Binocular disparity: the slightly different views of the world from both eyes. Zorgt voor stereo vision! Horizontal binocular disparity: a binocular dpth cue based on the difference in the horizontal retinal position of an image point in one eye relative to the other; often abbreviated to disparity. Far disparity: the horizontal binocular disparity created by an item that is further away than fixation distance; it is also known as uncrossed disparity. Near disparity: the horizontal binocular disparity created by an item that is nearer than fixation distance; it is also known as crossed disparity. Random-dot stereogram (RDS): a stereogram containing pseudo-randomly arranged dots; some dots are in disparate location in one eye’s view relative to the other eye’s view. Figure 10.15 page 313. Stereogram: an image designed to create an impression of depth when viewed binocularly; different parts of the image are seen by the two eyes. Diplopia: double vision; the observer sees two images of the same object simultaneously. Physiology: ? Stereoblindness: the ability to see depth is missing, people see 2D. Correspondence problem (in RDS): the problem of matching up two images point by point; the two images may depict the same scene at different viewing positions or times. Similarity, continuity, epipolar geometry 19 Janneke Martens Epipolar plane: the plane that passes through a given point in front of the viewer, and through the nodal points of the two eyes. Epipolar line: the projection of the epipolar plane onto the retinal image. Zie ook nog figuur 10.16 page 316. Chapter 11 Figure-ground segregation: when a kameleon moves you can see it, otherwise not. Extraction of three-dimensional structure: looking at a turning earth globe, you notice a speed difference between the equator and the poles. Visual guidance of action: the pattern of optic flow! (zie sheets) Motion detector: a neuron in the visual system that responds more strongly to retinal image motion in one direction than to motion in the opposite direction. Figure 11.2 page 328 Reichardt detector: a specific form of neural motion detector, which combines signals initiated at slightly different times from adjacent retinal locations. velocity sensitive!! Aliasing: a type of signal distortion that occurs when samples are taken at too low a rate for the signal frequency; the apparent frequency of the signal is altered. Motion after-effect (MAE): following adaptation to movement in a given direction, a stationary pattern appears to move in the opposite direction. “Spiraal draait terug”; figure 11.5 page 332. Direction-specific threshold elevation: Following adaption to movement in a given direction, thresholds for detecting movement in similar directions are elevated/harder to detect. Het is interocular transfer, eerst met ene oog adapteren en dan kijken met het andere en je ziet het bewegende object nog steeds (adaption), neurons liggen dus in de cortex. Strategies to separate object motion and observers motion: Saccadic suppression: during rapid shifts in eye position (saccades), vision is suppressed. Eye movement commands: slower eye movements; the visual system compares the commands sent to the ocular muscles to initiate eye movements against signals arriving from motion detectors. If equal and opposite, they cancel each other out. Large-scale motion: the visual system tends to assume that large-scale movements reflect observer motion rather than world motion, whereas localized relative motion is assumed to reflected object motion. Real movement: echte bewegingen Apparent movement: zoals in een film, statische beelden zorgen voor een gevoel van beweging. Stroboscopic apparent movement: apparent movement seen in patterns that are briefly flashed in different spatial positions. Rigid planner motion: figure 11.9 page 337 Aperture problem: the ambiguity present in the response of an individual motion detector, caused by the limited spatial extent of its receptive field; true stimulus direction cannot be determined uniquely. Velocity space (intersection-of-constraints): a graph in which arrows or vectors represent motion signals; the length of each vector specifies the speed of a signal, and angle specifies direction. Plaid: a pattern of criss-crossing stripes, created by adding together two sine wave gratings at different orientations. Kinetic depth: the impression of depth seen in the two-dimensional image of a moving threedimensional object; the depth is apparent only when the object. Position-based theories: keeps track of the position of features in the image over a series of static snapshots of the moving object. Motion-based theories: #D structure is inferred from the retinal velocities of points in the image, rather than from their position. more likely 20 Janneke Martens Biological motion: the perception of a moving biological form, either human or nonhuman, when the body is visible only by means of light points attached at joints. Random-dot kinematogram (RDK): a two-frame motion sequence containing pseudo-randomly arranged dots; some or all dots shift location in one frame relative to the other to offer a signal for motion detaction. First-order motion display: a motion stimulus containing shapes defined by variations in luminance. Second-order motion display: a motion stimulus containing shapes defined by variations in texture, with no corresponding variation in luminance. (filmpje les, er verschijnt streep) Figure 11.15 page 346 Feature tracking: a method of detecting retinal image motion; certain features in the image are identified, and their change in position is tracked. Second-order motion detectors: motion detectors can be subdivided into 2 classes. 1: encodes the motion of first-order patterns & 2: encodes the motion of second-order patterns. (FRF!!) Transformational apparent motion: figure 11.16 page 349. Chapter 13 Figure 13.1 page 383 Modular processing: a theory of cognitive processing in which different functions such as vision, hearing, and memory are implemented in separate and independent processing modules. Cross-modal cuing: occurs when a cue stimulus presented in one sensory modality facilitates the detection or discrimination of a target stimulus presented in a different sensory modality. McGurk effect: a perceptual interaction between vision and hearing in which visual observation of a speaker’s lips alters perception of speech sounds. Exogenous attention: involuntary, automatic orienting towards a sudden change in sensory stimulation. Superadditive response: a response to a combined stimulus that is greater than the sum of the responses to each stimulus presented separately. Event-related potentials (ERPs): minute fluctuations in electrical potential in the brain caused by changes in sensory stimulation. Synthesia is an intriguing and controversial multisensory phenomenon in which stimulation in one sensory modality causes a sensory experience in another modality. Chapter 14 Several factors are known to produce consistent individual differences in perception Age figure 14.1 page 400 Visual acuity: improves dramatically in the first 5 years! Infants do not have as much and long cones yet; Hearing: age related deafness (presbycusis); changes in the resonance of the outer ear, middle ear effusions in very young infants, immaturity in the cochlea for improvement. Deterioration in cochlear hair cells, decreased flexibility in the basilar membrane, decreased efficiency of sound transmission through the middle-ear ossicles presbycusis factors Smell: Touch: the decline can be partly attributed to changes in the mechanical properties of the skin & reduction in the number of touch receptors. Brain: figure 14.3 page 403. First years of life there is growth in dendrites and axons. White matter: tissue in the brain and spinal cord containing cell axons Gray matter: tissue in the brain and spinal cord containing neuronal cell bodies. 21 Janneke Martens Myelin: a fatty sheath covering certain cell axons; it facilitates the transmission of neural impulses. There is myelin break down when you get older. Sex figure 14.4 page 405 Mental rotation: the manipulation of an internal mental image of a shape, so that it is visualized from a different viewing angle. Biological differences and differences in experience and socialization between men and women. Culture Pictorial competence: the ability of an observer to make meaningful and accurate interpretations of pictorial images. Geometrical illusion: a figure containing simple geometrical forms, designed so that parts of the figure appear distorted in size or angle. Oblique effect: reduced visual acuity for oblique lines and gratings, relative to vertical and horizontal orientations. Expertise Formal training Shape constancy: the apparent shape of an object remains constant despite gross changes in its retinal image caused by variations in viewing position. Practice 22 Janneke Martens Human Performance Samenvatting – Human Factors Engineering Chapter 1 – week 1 Human factors has as goal to make the human interaction with systems one that enhances performance, increases safety and increases user satisfaction. Het ene doel kan ten koste van ’t andere. Usability: the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use. Zie figuur 1.1 blz. 3. Changes in the equiment design, task design, environment design, selection and training can contribute to a solution after the problem is identified. Human factors is goal-oriented instead of content-oriented, therefore there are no precise boundries. Chapter 2 – week 1 Scientific research: the goal is to describe, understand and predict relationships between variables. Applied science: The development of theory, principles, and findings that are relatively specific with respect to particular populations, tasks, products, systems, and/or environments. Human factors involves the application of science to system design. Basic research: The development of theory, principles, and findings that generalize over a wide range of people, tasks, and settings. This also applies to human factors. Experiment: involves looking at the relationship between causal independent variables and resulting changes in one or more dependent variables. Step 1. Problem&hypotheses, 2. Experiment plan, 3. conduct study, 4. Analyze data and 5. Draw conclusions. • Two-group design: control group no condition; experimental group 1 condition afh. variabele. • Multiple group design: more groups, many levels of one independent variable. • Factorial design: more groups, many levels of more independent variables. (efficient, captures a greater part, interaction between ind. variables. • Between-subjects design: different groups of subjects are used for each level of the condition. • Within-subjects design: the same subject in all of the experimental conditions. Order effect: when people participate in several treatment conditions, the dependent measure may be different from one condition to the next simply because levels are in a specific order. • Mixed design: both use of between- and within-subjects design • Multiple dependent variables: the name speaks for itself. Controled variables: extraneous variables that can be controlled Confounding variables: interference by a third variable so as to distort the association being studied between two other variables, because of a strong relationship with both of the other variables. Counterbalancing: different subjects receive the treatment conditions in different order. Type I error: accidently concluding that it was significant, when it was not. Type II error: concluding that experimental manipulation did not have an effect when it in fact did. Descriptive: researchers simply measure a number of variables and evaluate how they are related to one another. • Observation: taxonomy 23 Janneke Martens • Surveys and questionnaires: concern is the validity of a questionnaire. • Incident and accident analysis: look at the sheets week 1, nr. 30-32 • Literature surveys: can often substitute for the experiment itself. Houdt rekening met de ethische aspecten die komen kijken bij proefpersonen Chapter 3 – week 1 Cost/Benefit Analysis: the expected costs of the human factors effort and estimated potential benefits in monetary terms. Benefits are complex and domain specific. Sheets week 1, nr. 46&47 User-Centered design: center the design process around the user. Sheets week 1, nr. 41 Usability engineering: four general approaches; 1. Early focus on the user 2. Empirical measurement 3. Iterative design (using prototypes) 4. Participatory design (users are part of the design team) sheet 43. Product design models included stages reflecting pre-design or front-end analysis activities, design of the product, production, and field test and evaluation. Product lifecycle models also add product implementation, utilization and maintenance, and disposal to the model. 1. Front-end analysis to understand the users, their needs and demands. b. environment analysis c. function & task analysis a. User analysis i. Task analysis activity analysis/preliminary task analysis: job, duty, task & action. 2. Iterative (herhalend/hervattend) design and test 3. System production 4. Implementation and evaluation 5. System operation and maintenance 6. System disposal Hawtorn effect: when a person or project is given more attention, his or it’s performance improves, even when the attention is negative. Chapter 9 – week 2 Control: knowing the state of affairs, knowing what to do, and then doing it! zie schema sheet 2, w2. It is a noun (a control; zelfst. nw) en een verb (to control; werkw.) figuur 6.1, page 122. Response selection: the difficulty & speed of selecting an action/response is influenced by several variables. Namely.. Decision Complexity: the speed with which an action is selected is strongly influenced by the number alternative actions. Hick-Hyman law: dependency of response selection time on decision complexity = + log with RT=response time; a = ?; b= ?; N= # alternatives. Decision complexity advantage: small number of complex decisions is better than a large number of simple decisions. Expectancy: Expected information is perceived more rapidly and accurately than unexpected information (Ch. 4,6 & 8). This is the same with selection, we choose what we expect to carry out than those that are surprising. Compatibility Stimulus-response compatibility: the relationship between the location of a control or movement of a control response and the location or movement of the stimulus or display to which the control is related. 24 Janneke Martens Location compatibility: the control location should be close to the entity being controlled or the display of that entity. Movement compatibility: the direction of movement of a control should be congruent with the direction both of movement of the feedback indicator and of the system movement itself. Speed-accurancy tradeoff: when you’re faster, you’re less accurate. And vice versa. (negative correlation between speed & accurancy. Feedback: most controls and actions that we take are associated with some form of visual feedback that indicates the system response to control input. Discrete control activation Physical feeling: knipperlicht (3dingen) Immedacy: onmiddelijk Redundancy: overtollig op sheet “ “ Size: how smaller how harder to reach. Confusing labeling Good conceptual mapping in sheet stoelvorm van de knop om de stoelpositie te veranderen. Positioning control: Movement of a controlled entity, which we call a cursor, to a destination, which we call a target. Movement time: movement to reach the control & movement to position the cursor take time. Fitts’s law: movement time can be predicted by this model. = + log 2 ⁄! with A= amplitude of the movement, W=width of the target and MT = movement time. 2A/W is the index of difficulty Direct position control (iPhone) vs. indirect position controls (mouse) vs. indirect velocity controls (joystick). The last one is devided in 3 sorts: isotonic (moved freely & will not return back to startpoint), isometric (?) en spring-loaded. Gain: " = #ℎ %&' () #*+ (+⁄#ℎ %&' () #(%,+(- .( /,/(%. High gain is small displacement of control produces a large movement of the cursor. (How much output the system provides from a given amount of input.) Feedback: salient, visible & immediate (slide 21) The device choice is dependent on the task and on the work space environment. Verbal & symbolic input devices: input via keyboeard or voice control Numerical data entry: linear array, calculator style & telephone style. Linquistic data entry: QWERTY, chording keyboard (10toetsen+combinaties) & Dvorak keyboard Voice input Benefits: useful in time-sharing activities in which the visual and manual modalities are both occupied (e.g., car driving) Costs: it is complex & developing. Confusion and limited vocabulary size. Constraints on speed. Acoustic quality and noise and stress. Compatibility. Continuous control: tracking a moving target. Tracking: the task of making a system output correspond in time and space to a time-varying command target input. (vliegen vangen) Tracking loop: fig. 9.4 page 232; slide 29, w2. System dynamics: the relation between u(t) & o(t), the control output en de system output. 2 sources of errors: command inputs ic (bocht in weg) and disturbance inputs id (windvlaag) Fig. 9.5 page 233. Fig. 9.6 page 235. Control order Position (zero order), velocity (first-order), acceleration (second order) 25 Janneke Martens Stability: instability results from 3 factors: 1. There is a lag in the total tracking loop. 2. The gain is to high. 3. Human operator is correcting to rapidly, does not wait for the systems lag. Closed-loop vs. open-loop systems Solutions: 1. Predictive displays 2.Teach the tracker strategies of anticipation. For example, experienced drivers look further down the road than novices do. 3. Automateto bring it to a lower-order control. Also see sheet 33&34. Chapter 16 – week 2 Reasons for automation: 1. Impossible or hazardous tasks (e.g., special needs population) 2. Difficult or unpleasant tasks (e.g., vigilant monitoring) 3. Extending human capabilities (e.g., memory aids) 4. Cost reduction (e.g., automated phone menus) 4 stages of automation: 1. Detection/monitoring (e.g., oil light or spell-checker) 2. Information integration (e.g., route planning) 3. Action selection and choice (e.g., collision avoidance system) 4. Control and action execution (e.g., cruise control) Stage 3 & 4 can be devided in to 8 levels: 1.No automation; human in control 2.Automation suggests multiple alternatives 3.Automation suggests one alternative 4.Automation carries out action if person approves 5.Automation provides human limited time to veto the action 6.Automation carries out action, then informs human 7.Automation carries out action, informs only when askes 8.Automation carries out action, ignores the human (no veto, no information) Automation reliability: 1. May be unreliable 2. Certain situation in which it fails or is not designed for 3. Incorrectly “set up” (dumb & dutiful) 4. Appear to be acting erroneously Trust should be in direct proportion to the reliability of the agent, humon or computer. Otherwise mistrust. If the person fails to trust the automation as much as appropriate distrust. When people trust the automation more than is warranted: overtrust (complacency). When overtrust detection of an error is later, there is less situation awareness, there will be skill loss in the long term. Fig.16.1 p 426 Also look at the sheets 40-42! Function allocation: to decide a human or device or a combination of both is better for a task/job. Ideally human-centered automation: 1. Keeping the human informed 2. Keeping the human trained 3. Keeping the operator in the loop 4. Selecting appropriate stages and levels when automation is imperfect 5. Making the automation flexible & adaptive 6. Maintaining a positive management philosophy. Fig. 16.2 page 432: continuum of shared responsibility ook slide 39. Chapter 8 – week 3 Display: a human-made artifact designed to support the perception of relevant system variables and facilitate the further processing of that information. Display = medium between system and operator’s perception and awareness. User’s mental model: perception & awareness of how the system functions. The display concept is often closely linked with that of the graphical user interface (GUI). The key mediating factor that determines the best mapping between the physical form of the display and the task requirements is a series of principles of human perception & information processing. Before fabricating a display, know what the task is that the display is supposed to support with tools. Perceptual principles zie ook fig. 8.2, page 187. P1. Make display legible (or audible). P2. Avoid absolute judgment limits. (wanneer rare kleur = vaag of ‘t nou rood of groen is.) 26 Janneke Martens P3. Top-down processing. (checklist) P4. Redundancy gain. ?? (traffic light) P5. Discriminablility. Similarity causes confusion: use discriminable elements. Mental model principles P6. Principle of pictorial realism. Display should look like the variable it represents. P7. Principle of moving part. When airplane is going up, monitor should also indicate up. Human attention (selective attention, focused attention, divided attention) P8. Minimizing information access cost. As little traveling time as possible between displays. P9. Proximity compatibility principle. Nabijheid & vereenigbaarheid = goed! P10. Principle of multiple resources. Soms beter om visually &;or auditory instead of just on. Human memory: P11. Replace memory with visual information: knowledge in the world. Checklist. P12. Principle of predictive aiding. Proactive is better than reactive. P13. Principle of consistency. Old habbits die hard. Alerting display omnidirectional auditory is best when the operator has to be alerted when critical. 3 levels: warnings, cautions and advisories (critical less critical) P4&P5 Labels: present knowledge about the identity of something, P11. Visibility/legibility (P1), discriminability (P5), meaningfulness (P4) & location (P9). Monitoring displays: 1. Legibility (P1), 2. Analog vs digital (P4 P6), 3. Analog form and direction (P3 P6 P7) & 4. Prediction and sluggishness (P11) Multiple displays layout: determine Primary Visual Area (PVA) 1. Frequency of use (P8) 2. Importance of use 3. Display relatedness or sequence of use (P9) 4. Consistency (P8 P13) (T shape) (salient visible, consistency, resist excessive flexibility. 5. Organizational grouping (P8 P9) 6. Stimulus-response compatibility & clutter avoidance Head-Up Display: superimpose the displayed information on top of the PVA. Beeldscherm auto. (P8 P9) costs: to much superimpose, overlapping imagery Head-Mounted Display: met bril. (P9) monocular, binocular or binocular. Configural displays: meerdere schermen met alleen 1 variabele vormen samen een geheel. Navigation display (maps): 4 fundamentally different classes of tasks. 1. Provide guidance 2. Facilitate planning 3. Help recovery 4. Maintain situation awareness. Most simple map: command display. Maps: legibility, clutter & overlay, position representation, map orientation, scale, 3D-maps and planning maps & data visualization. Quantitative info display (tables & graphs) consider precision in choosing which one. Fig. 8.15-18; p. 214 Legibility (P1): discriminability (P5), redundant coding (P4) Clutter: data-ink ration (meeste data, minste inkt) Proximity: (P8 P9) Format: data visualization Chapter 4 Saturated wavelengths: are on the spectrum, they are not diluted with gray or white (achromatic light). Illumination: the lighting quality of a given working environment. Reflactance (%) = luminance(FL)/illuminance(FC) (table 4.1; page 65) Brightness: the actual experience of visual intensity, determines its visibility. Fig. 4.3; page 66 & table 4.2; page 68 27 Janneke Martens Rods & Cones differ in properties, namely: location in the eye, acuity (how much detail), sensitivity (threshold), color sensitivity, adaptation, and differential wavelength sensitivity. Sensory processing limitations Contrast Sensitivity (CS): fig. 4.4; p. 70, tab 4.3; p. 72 Night Vision (glare: irrelevant light of high intensity) Color vision Bottum-up vs top-down processing fig. 4.6; page 74 Depth perception bottom up: accommodation, convergence & binocular disparity Linear perspective, relative size, interposition, light and shading, textural gradients & relative motion. Eye movement Pursuit movements Saccadic movements 3 features: initiation latency, movement time, destination (or dwell dwell duration (2 factors: information content & information extraction) & useful field of view (UFOV)) Visual search The serial search model: targets & nontargets (Time=(NxI)/2) Conspicuity (table 4.4; page 81) & Expectancies Signal detection theory: figure 4.9; page 83 Absolute judgment: refers to the limited human capability to judge the absolute value of a variable signaled by coded stimulus. Chapter 15 – week 4 Usability: efficiency, accuracy, learnability, memorability and satisfaction. 1. Involvement of users from the begin 2. Guidelines and principles 3. Iterative usability testing Figuur 15.1; page 387 Understanding Functionality (number & complexity of things) Creeping featurism (everyone wants more apps) Frequencie of use Mandatory or discretionary use Knowledge level user: novice, knowledgeable intermittent of expert frequent user Graphical user interface (GUI): good for novice users. Design Seven stages of action (by Norman): fig 15.2; page 391! Gulf of evaluation: understanding the state of the system and establishing goals. Gulf of execution: understanding what to do to accomplish those goals and how to do it. Goals, operators, methods, and selection rules (GOMS): identify user’s goals, identify all methods, and write selection rules. Conceptual model: the general conceptual framework through which the functionality is presented. (Designers want to promote an accurate mental model, using this and metaphors) Making invisible parts visible, feedback, building in consistency and using metaphors. General usability guidelines (for translating the conceptual model into syntactic components. In table 15.1; page 398. By Nielson. Basic Screen Design Dialog Styles 28 Janneke Martens Menus, Fill-in Forms, Question-Answers, Command Languages, Function Keys, Direct Manipulation, Natural language. Software Manuals (users search on goals and tasks, not on system components or names.) table 15.2; p. 405 Online Help Systems Evaluate With usability heuristic Chapter 3. Less time and less expensive than usability test. 2-4 experts With usability test and metrics, these involve typical users. Prototypes, usability metrics (p. 408) 2 valkuilen: understanding user & task is important, otherwise it will be nothing & laboratory environment is sometimes a bias. Information Technology Hypertext (woorden klikken Wikipedia), hypermedia(zelfde maar dan met meer dan alleen tekst) & Internet Information database access (mediated retrieval, intelligent agents, spatially organized databases (getting lost, update rate)) p. 414, fig. 15.4 Virtual and augmented reality Affective computing Information Appliances Chapter 6 – Sharp – week 4 Paradigm: a particularly approach that has been adopted by the community of researchers and designers for carrying out their work, in terms of shared assumptions, concepts, values and practices. Ubiquitous Computing (UbiComp): design computers as a part of the environment. Below a selection of interfaces. 1980s interfaces • Command like delete or ctrl + b • WIMP/GUI Windows, Icons, Menus and Pointers, the early GUI 1990s interfaces • Advanced graphical (multimedia, virtual reality, information visualization) • Web • Speech (voice) • Pen, gesture, and touch • Appliance include machines for the home, public place or car. Remotes, washing machine and navigation 2000s interfaces • Mobile • Multimodal • Shareable more people working on 1 display at the same time • Tangible sensor based interaction; bricks & balls are coupled with digital representation. physical objects and digital representations can be positioned, combined, and explored in creative ways, enabling dynamic information to be presented in different ways. • Augmented and mixed reality virtual representations are superimposed on physical devices and objects &views of the real world are combined with views of a virtual environment. Een bril waar je door heen kunt kijken en dat er dan bijv. Instructies op de gelazen verschijnen. • Wearable • Robotic glasses with information for example. 29 Janneke Martens Chapter 19 – week 5 Individual behavior: a function of the social context (attitudes & behavior) Function of the organizational context: management structure, reward or incentive systems, enz. The interaction between individuals, technology and environment. Complexity: the number of feedback loops, interconnectedsubsystems, and unexpected interactions. Table 19.1; page 493 Coupling: the degree that there is little slack & a tight connection between subsystems. Tightly coupled systems require centralization & highly complex systems require decentralization Group: aggregations of people who have limited role differentiation and their decision making or task performance depends primarily on individual contributions. (jury or board of directors) Team: small number of people with complementary skills and specific roles or functions (high role differentiation), who interact dynamically toward a common goal. Multiple people, independent manner Points on page 497 and page 498. Computer-supported cooperative work (CSCW): using computers to support group or team activity. Group communication support systems & group decision-support systems. Group-view displays: provide a status overview, direct personnel to additional information, support collaboration among crew members and support coordination of crew activities. Microergonomics: making changes in the workstation or physical environment for individual workers. Macroergonimics: addresses performance and safety problems. Combine jobs, technological systems, and worker abilities to harmonize with organizational goals and structure. Participatory ergonomics: a method whereby employees are centrally involved from the beginning. (employees know much, employee and management ownership enhances program implementation and flexible problem solving. Chapter 5 Frequency corresponds to its pitch and the amplitude (intensity/ratio of sound pressure (P in dB)) to its loudness. Envelope: temporal characteristics of sound stimulus. Makes distinguish possible between siren & noise. The ear, see figure 5.2; page 94 Loudness & intensity don’t directly correspond. Psychophysical scaling of loudness in sones (fig. 5.3; page 96) loudness doubles with each 10dB intensity. Modifying effect of pitch (frequency scaling). (fig 5.4; page 97) Alarms Omnidirectional: we can sense auditory signals no matter how we are oriented. You can’t ‘close’ your ears as easily as you can do that with your eyes. • 30 dB above noise, not above danger level of hearing (85dB), not abrupt but rise time, should not disrupt the perceptual understanding of other signals and it should be informative. o Environmental and task analysis, guarantee informativeness & minimize confusability (limits of absolute judgement) and specifics of the individual sound (fig. 5.6; p. 101). Limits of voice alarms: more confusable with background noise, more sensitive for masking, language problem. Redundancy gain is a fundamental principle. Articulation index (AI): the signal-to-noise ratio (speech dB – noise dB) Noise Temporarily or permanently threshold shifts (TTS or PTS) Other senses 30 Janneke Martens Proprioceptive channel: receptor channels convey to the brain an accurate representation of muscle contraction… ? … Kinesthetic channel: receptors in muscles which convey a sense of the motion of the limbs as exercised by the muscles. (veel overgeslagen uit hoofdstuk, logisch en in deel 1 ook al gehad.) Chapter 13 – week 6 Stress figure 13.1; page 325. Stressors have the following effects: produce a psychological experience, a change in physiological characteristics, effect the efficiency of information processing and long term negative consequences for health. Direct: influence the quality of information received by the receptors or precision of response. Environmental stressors: lightning (ch4) & noise (ch5); all physical measure. Cyclic motion/vibration: high frequency performance decrements or repetitive motion disorders & low frequency motion sickness Thermal stress: stay within the comfort zone, else workers get heat/cold stress. Air Quality: poor air quality have negative influences op perceptual, motor & cognitive performance. Indirect: influencing the efficiency of information processing through mechanisms. Psychological stressors: resulting from the perceived threat of harm or loss of esteem. Cognitive appraisal: the amount of stress is dependent of the appraisal. Ethical issues: Level of arousal: optimum level of arousal (OLA); fig. 13.2; p. 331, inverted U function Performance changes with overarousal: tunnelvision Knowledge should be in the world, ch 6&8, not holding on in working memory. Life stress Workload overload: ratio between time required and time available. Fig. 13.3; p. 335. Timeline model. Figure 13.4; page 335. IMPORTANT! (ID of task times, scheduling & prioritization, task resource demands & automaticity and multiple resources.) Consequences: something is likely to suffer. Training on the component tasks (faster & automated) or on task management skills. Timelines have limits, focus on other ways to measure the resource demands of tasks. Fatigue & sleep disruption Key characteristics of the environment that lead to loss of performance in detecting signals or events of relevance: time, event salience, signal rate & arousal level. Circadian Rhythms: time in the day-night cycle. Fig 13.5&13.6; page 345&346. Jet lag stronger when traveling east than west. Shift work: best option = slow shifts (several days same shift, than switch) and the changes must be clockwise (delayed) instead of counterclockwise. And NO long shifts! Chapter 6 Information-processing system, 3 stages: 1) perception of info about the environment 2) central processing or transforming that info and 3) responding to that info. 1&2 are involved in cognition. Figure 6.1; page 122! IMPORTANT! Top-down processing. Selective attention does not guarantee perception, but is usually necessary. Selection of channels to attend, 4 factors: Salience, bottom-up, attentional capture (i.e. a car horn). Attentional blindness. Effort, ?, may be inhibited if it’s effortful. 31 Janneke Martens Expectancy, top-down, sample the world where we expect to find info. Value, top-down, how valuable is it to look at a display, or how costly to miss an event. Percerption proceeds by 3 often simultaneous & concurrent processes: 1) bottom-up feature analysis, 2) unitization (set van eigenschappen die samen voorkomen, geleerd uit eerdere ervaring) & 3) top-down processing. Guidelines: 1. Maximize bottom-up processing 2. Maximize automaticity & unitization 3. Maximize top-down processing. Perception is ‘automatic’, long perceptual process becomes comprehension (less automatic) word vs sentence. Working memory: a central executive component (control system, it coordinates), the visuospatial sketch pad (hold info in an analog spatial form, visual imagery, while used) and the phonological loop (verbal info in a acoustical form, kept active by repeating the telephonenr for example). Capacity: 7+-2 chunks; Time: 1 chunk +- 70 s, but maintenance rehearsal makes it longer; Confusability & Similarity: between the features of different chunks is not good; Attention & Similarity: resource limited, when focusing on something else, rehearsal will stop, decay is more rapid. Minimize working memory load, provide visual echoes, provide placeholders for sequential tasks, exploit chunking (physical chunk size, meaningful sequences, superiority of letters over numbers & keeping numbers separate from letters), minimize confusability, avoid unnecessary zeros in codes to be remembered & consider working memory limits in instructions. Negation Long-term memory: learning is the process for storing information, training. Semantic memory, facts or procedures, & event memory, specific events. Strength of an item: determined by the freauency and recency of its use. Associations of an item with other items. Rote memory: rehearsing by repetition instead of actively seeking meaning through associations, is more rapidly forgotten Database structure in the same way as the organization of the user’s semantic network. Or following the next organization structure: schemas & scripts, mental models and cognitive maps. Design: 1. 2. 3. 4. 5. 6. Encourage regular use of information to increase frequency and recency. Encourage active verbalization or reproduction of information that is to be recalled. Standardize. Use memory aids Carefully design information to be rememberd. Design to support development of correct mental models. Figure 6.2; page 140 episodic memory (event memory) Situation awareness, SA: the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future. (perception, understanding & prediction) SA for implications for designing easy-to-interpret displays , SA important for accident analysis, SA implications for training. Predict state & command state of a dynamic system. Metacoginition/metaknowledge: knowledge about their own knowledge and abilities. Anticipated effort: required to gain the additional information. Divide attention: the ability to do two or more things at one time. Resource theory: scarce mental resources are shared by tasks & more difficult task leave fewer resources for concurrent task, whose performance declines as a result. Automaticity closely related to mental effort. Structural similarity: similarity between key processing structures of both tasks in a concurrently performed pair. Table 6.1; page 152. 32 Janneke Martens Chapter 14 – week 7 Safety concerns with injury-causing situations; accidents from acute conditions Health concerns with disease-causing situations; prolonged conditions like poor design keyboard. Next to negligence claims, there are strict liability claims; meaning that a manufacturer of a product is liable for injuries due to defects without a necessity for the injured party to show negligence or fault. Product liability claims: alleging that a product was somehow defective & the defect cased the injury or death. (design, manufacturing, or warning defect) Is a product defective or inherently “dangerous”? Defective when it failed to perform safely as an ordinary user would expect when it was used in an intended or reasonably foreseeable manner, or if the risks inherent in the design outweighed the benefits of that design. (reasonably foreseeable & tradeoff between risk and benefit) Systems approach assums that accidents occur because of the interaction between system components Figure 14.1; page 357 and Table 14.2; page 358. Goed bestuderen. Clasifications • Errors of commission: operator does something that should not have been done. Delete ipv save. • Errors of omission: operator fails to do something that should have been done. Forgetting to save. Commission/omission helps with what was done, but not with why it was done. • Mistake: action which turned out to be inappropriate was intended o Knowledge-based mistakes: knowledge in head or world fails to help human with understanding the situation. (failures of understanding & perceptual errors) o Rule-based mistakes: human is unaware of the rules governing appropriate behavior. • Slip: the incorrect act wasn’t intended, but “slipped out” through the selection of action. • Lapses: failure of prospective memory. • Violation: human does intentionally something inappropriate. Hazard criticality ≈ risk, combination of probability, likelihood of an event taking place, and severity, scaled to the severity of the injury, of the event or accident. • Preliminary hazards analysis • Failure Modes and Effects Criticality Analyses(FMECA) • Fault Tree Analysis, figure 14.3; page 373. Safety Management 1. Identify risks to the company 2. Develop and implement safety programs 3. Measure program effectiveness Risk-taking and warnings Intention to behave safe: 1) variables related to perceived severity of the hazard 2) the novelty of the hazard and whether exposure was voluntary & 3) how familiar the product or item was to person. Warnings: zie sheets; danger/warning/caution (figure 14.5; page 382). Chapter 17 – week 8 Baseline is important when showing grades about something, like fatality rates. Baseline can be biased by certain segments of the population. Young vs old drives. Strategic tasks: the purpose of the trip and the driver’s overall goals. (where & when to go) Tactical tasks:the choice of maneuvers and immediate goals in getting to a destination. (speed, inhalen) Control tasks: the moment-to-moment operation of the vehicle. (maintaining speed & lane) Lateral task: ?; maintaining lane position, second order control task. Longitudinal task: ?; speed keeping, first order tracking task 33 Janneke Martens Figure 17.1; page 439. Primary Visual Attention Lobe (PVAL) 4 main categories of visibility issues: Anthropometry (seating & reachability), illumination, signage (minimize visual clutter, locate signs consistently, identify sign classes distinctly & allow signs to be read efficiently) and resource competition (in cap viewing; radio, maps, switches & phones). 4 things that threaten driver’s safety: (figure 17.2; page 446) 1. 2. 3. 4. Increases the likelihood of control loss Decreases the probability that a hazard will be detected in time Increases the distance traveled before a successful avoidance maneuver can be implemented Increases the damage at impact Fatigue, drunk, age and angry doesn´t improve your driving skills. Table 17.2; page 450. Table 17.3; page 456. Trust & complacency, attention may be drawn more into the vehicle, introduce a new type of productivity and safety tradeoff in driving. Chapters 7, 10, 11, 12 & 18 aren’t included in the exam. 34
