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102 Cards in this Set

  • Front
  • Back
Transduction
In the senses, the transformation of environmental energy into electrical energy. For example, the retinal receptors transduce light energy into electrical energy.
Psychophysical methods of measurement
Method of limits (ascending or descending)
Method of adjustment - subject's in charge
Method of constant stimuli - randomization
Weber's Law
A law stating that the ratio of the difference threshold (DL) to the value of the stimulus (DL/S) is constant. According to this relationship, doubling the value of a stimulus will cause a doubling of the difference threshold. The ratio DL/S is called the Weber fraction.

JND
White light
- The most complex light appears white
- Multiple wavelengths
- De-saturated (saturated is one wavelength)
Absolute threshold & JND
- the minimum intensity at which he/she can accurately detect the stimulus 50% of the time
- JND is “Just Noticeable Difference”
Retina; cones/rods
- rods – 120 million
- cones – 6 million
Fovea
- A small area in the human retina that contains only cone receptors. The fovea is located on the line of sight, so that when a person looks at an object, the center of its image falls on the fovea.
Blind spot
– at the end of the optic nerve
– no receptors (pushed away by the optic nerve)
Simple, complex, hypercomplex cells
Simple cells – respond only to lines; diff cells/for each line orientation\
Complex cells – respond only to moving lines; diff cells for diff directions
Hypercomplex cells – only respond to moving corners; also called End-stopped cells because they stopped firing if the corner lines were too long
Proximal/Distal stimuli
o Distal – the object in the environment
o Proximal – the pattern of receptivity on the retina
o Therefore, the distal stimulus “gives rise” to the proximal stimulus
Accommodation
- (changing shape)
- ciliary muscles, contract and relax, causing tension in the zonal fibers causing the lens to change shape (accommodation)
- when the ciliary muscles tighten, the zonal fibers relax, and the lens gets bigger, and vice versa
Ipsilateral & Contralateral
images crossing at the optic chiasm
Dorsal & Ventral pathways
Dorsal pathways – rods – primitive – parietal – where
Ventral – cones – conscious – temporal – what? – object recognition
Parietal & Temporal lobes
• Parietal - Pathway that conducts signals from the striate cortex to the parietal lobe. This is also called the where, the how, and the action pathway to indicate its function.

• Temporal lobe A lobe on the side of the cortex that is the site of the cortical receiving area for hearing and the termination point for the ventral, or what stream for visual processing. There are a number of areas in the temporal lobe, such as the fusiform face area and the extrastriate body area, that serve functions related to perceiving and recognizing objects.
Wavelength
the distance between a full wave to complete

colors
color / hue
different colors correlate with different wavelengths
wave height/ amplitude
o the height of the crest of the wave from the middle
o a measure of the amount of energy in the wave form, higher crest = more energy

brightness
Brightness
o The higher the wave length, the brighter the color
o Amplitude positively correlates with brightness
Complexity
o The number of pure wavelengths combined
o The most complex light appears white
o Imagine combining red green and blue light to get white
Saturation/ purity
- Most saturated light is composed of a single wavelength (red out of a paint tube)
- Most de-saturated light is white (made up of many wavelengths)
Ratio principle
the brain is able to maintain brightness/ lightness constancy by taking into account the ratio of light reflectance from the object and its surroundings
Lightness constancy
If there is more light, the whiter it appears
- refers to our ability to perceive the same, “whiteness or blackness” in spite of large differences in how much light is being reflected back to the eye
o a pen’s black looks the same outside or inside
Gelb experiment
setup to test the ratio principal
o Shined a very bright light on a black disk and had observers look into the room. The black disk looked snow white because of comparing it to its surrounding. When a piece of paper is put over the circle it instantly turns black
Mach bands
– created by retinal enhancement of contrast differences at the border that separates two objects; refers to a “lighter-than-light” thin line on the light thin border and a “darker-than-dark thin line on the darker object border” – see handout
– Mach bands are created by lateral inhibition processes on the retina
– Mach band - Perception of a thin dark band on the dark side of a light–dark border and a thin light band on the light side of the border. These bands are an illusion because they occur even though corresponding intensity changes do not exist.
Lateral inhibition
- because of the communication of our lateral cells (amacrine and horizontal cells), we see mach bands
- Inhibition that is transmitted laterally across a nerve circuit. In the retina, lateral inhibition is transmitted by the horizontal and amacrine cells.
Spatial summation/convergence
When many neurons synapse onto a single neuron
Dissociation
A situation that occurs as a result of brain damage in which one function is present and another is absent.
Modularity
Our brain – a number of modules that are semi-independent
Ablation
- Removal of an area of the brain. This is usually done in experiments on animals, to determine the function of a particular area. Also called lesioning.
Theory of Natural Selection
- The idea that genetically based characteristics that enhance an animal’s ability to survive, and therefore reproduce, will be passed on to future generations.
2nd exam
2nd exam
Inverse projection problem
Ambiguity because a particular image on the retina could have been caused by an infinite number of different objects.
- ex. Viewpoint invariance – humans can recognize objects from multiple viewpoints
Laws of Perceptual Organization
1. Gestalt Law of Prognanz (simplicity)
i. given several possible interpretations of a visual scene, the visual system refers the most simple (central Gestalt Law)
ii. every stimulus pattern is seen in such a way that the resulting structure is as simple as possible
a) Olympic rings as separate
2. Principle of Closure
i. the brain tends to “complete” otherwise “incomplete” contours
a) completing the triangle
ii. Ammodal Completion - the brain completes incomplete pictures
3. Principle of Meaning/Familiarity
i. familiar or meaningful objects are more likely to be grouped
a) ex. faces in the forest
4. Principle of Good Continuation
i. the visual system prefers contours (lines) that continue along their original path
a) the cord laying on itself
5. Principle of Proximity
i. objects close to each other belong together
6. Principle of Similarity
i. objects with similar features tend to be perceived as belonging together
7. Principle of Common Fate
i. when individual things move in a common direction
Trichromatic color theory
The operation of the ratio of activity between three different types of cones
ii. Long wavelength cones (Red)
iii. Medium wavelength cones (Green)
iv. Short wavelength cones (Blue)
Color matching
- observers are asked to match the color in one field by mixing two or more lights in another field.
o when shown any “pure” color (single wavelength) subjects could exactly match that color only when provided with three separate colors (red, green, and blue) that they could mix together (complex wavelength). This implies the operation of three distinct cone types
Metamers
- refers to colors that look the same but are composed of different wavelength distributions.
o how can a “pure” color (single wavelength) look the same as a color that is a result of mixing (complex wavelength)?
o The trichromatic color theory - Both the “pure” wavelengths and “complex” wavelengths forms cause the same ratio of firing among the three cone types
Opponent-process color theory
our perception of color is determined by the activity of two opponent mechanisms
o red vs. green
o blue vs. yellow
o black vs. white
Color naming studies
certain color combinations were never reported by subjects.
o Reddish green? Blueish yellow?
Color afterimages
- green - red after image
- blue - yellow after-image
- white light - black after-image
- all and vice versa
Forms of color blindness
Protanopia - red/ green color blindness

Deuteranopia - red/ green color blindness

Tritanopia - blue/ yellow color blindness
Cerebral achromatopsia
A loss of color vision caused by damage to the cortex.
Binocular cues to depth
convergence – brain keeps track of the convergent state of both eyes to determine distance to the object

binocular disparity – the brain uses “disparate” information from both eyes to determine distance to the object and distance from one object to another.
Monocular cues to depth
Pictorial – refer to monocular depth cues that can be used in a static 2-dimensional image or picture/ sketch

Non-pictorial cues – monocular cues that cannot be represented on a static 2-D image.
Pictorial
refer to monocular depth cues that can be used in a static 2-dimensional image or picture/ sketch
o Linear perspective – parallel lines appear to converge as distance increases
o Apparent size – all else being equal, smaller objects appear to be farther away
o Interposition (overlap) – the object that overlaps another object is assumed to be the closer of the two objects
o Texture gradient – as distance increases, the texture becomes increasingly homogeneous
o Shadow cue – brain assumes light comes from the top down. Shadow information can then be used by the visual system to recover shape (crater/innie or bump/outie)
o Height in the visual field – below the horizon, as one looks up, perceived distance decreases
o Atmospheric perspective – in general as distance increases, objects appear “bluer” and “fuzzier”
Non-pictorial cues
monocular cues that cannot be represented on a static 2-D image.
o Accommodation – the brain keeps track of the accommodative state of the lens; such that round lens = near, flattened lens = farther
o Motion parallax – as you move through the environment a near object will “overlap” a more distant object. The nature and rate of overlap provides information about distance to the objects and distance between the two objects.
• Accretion - More distant object become revealed
• Deletion – More distant object becomes “covered”
Steropsis
The brain combines the information from each eye in a process called stereopsis and this process gives us 3-dimensional visual perception
Stereoscope
A device that presents pictures to the left and the right eyes so that the binocular disparity a person would experience when viewing an actual scene is duplicated. The result is a convincing illusion of depth.
Visual angle
The angle of an object relative to an observer’s eyes. This angle can be determined by extending two lines from the eye—one to one end of an object and the other to the other end of the object. Because an object’s visual angle is always determined relative to an observer, its visual angle changes as the distance between the object and the observer changes.
Emmert’s Law/Size-distance scaling
Two inter-related problems
o Objects that produce identical retinal image sizes, can nevertheless be perceived to be different actual sizes
• Ex. The sun / moon eclipse
o Objects that produce different retinal image sizes, can nevertheless be perceived to be the same actual size
• Ex. A pen at five feet or 10 feet looks the same
Size-distance Invariance hypothesis
Brain takes distant into account
o Objects that produce identical retinal image sizes, can nevertheless be perceived to be different actual sizes
and
o Objects that produce different retinal image sizes, can nevertheless be perceived to be the same actual size
Emmert’s Law
mathematically formalized statement of the size distance invariance hypothesis
• Perceived size = retinal size x perceived distance
• Sp = Sr x Dp
• Zenith moon = 10,000 = 100 x 100
• Horizon moon = 20,000 = 100 x 200
Size constancy
Occurs when the size of an object is perceived to remain the same even when it is viewed from different distances.
Moon illusion
apparent distance theory
o Horizon sky appears more distant than the zenith sky
vaulted heavens / flat-dome
o vaulted heavens (flat dome) is how people perceive the shape of the sky.
Real vs. Illusory movement
Real motion – refers to our ability to perceive actual motion

Illusory motion – perceived motion but no actual motion
Illusory motion
perceived motion but no actual motion
o Apparent motion (stroboscopic): rapid sequential presentations of two stable objects leads to the perception of one object moving from one point to another
• An example is a rolling marquee
o Induced motion: moving background context causes stable object to appear to move
• Moving cartoon backgrounds, thinking the train is moving
o Autokinetic motion: a stable point of light in a completely darkened environment appears to move erratically; due to nystagmus (involuntary movement of the eyes)
o Motion after-effects: prolonged viewing of motion in one direction produces an opponent after-effect of motion in the opposite direction
• Ex. – waterfall effect
Real Motion
refers to our ability to perceive actual motion
o Factors affecting real motion perception
• Background – easier to see motion when background is heterogeneous (textured)
• Homogeneous threshold = 1/6 – 1/3 degree/sec
• Heterogeneous threshold = 1/60 – 1/30 deg/sec
o It can move a lot slower, but you can tell that it is moving
• Size of object – when moving at the same actual rate, a smaller object appears to move faster than a larger object
• Due to misapplication of speed constancy
Corollary Discharge theory
a structure in the brain called a “comparator” compares the motor signal sent from the brain to the sensory signal sent from the eye to brain.
- When the signals match there is no motion (brain interprets motion across the retina as due to eye movement alone)
- When the signals do not match then motion is perceived (motion across the retina due to object actually moving)
- So, if the comparator gets both motor and sensory signals together then no motion is perceived
o They tested this with curare – numbing the muscles in the eye
Perceptual Vector Analysis
suggests that motion perception of an object depends upon motion of the other objects nearby. This is a Gestalt theory
o Visual system breaks up the motion of individual objects into their basic vectors (directions of motion)
o Vectors that are in common are cancelled out
o The remaining vectors are the perceived motion. This is called relative motion
o 3 dots presentation
Gibson’s Ecological theory
all the information we need to perceive motion is provided directly on the retina (also called the direct perception theory)
Optical Flow Pattern
- f.o.e. – focus of expansion; as distance of viewing increases the rate of optic flow across the retina decreases until it reaches a point where all motion appears to start (e.g. the f.o.e.) This cue provides information about direction of motion
- Locomotor flow line: indicated the course of travel and provides feedback as how to change course of travel
• Ex. Driving in fog, changing your car based on the highways lines
- Rate of angular expansion: rate at which proximal stimulus changes size on retina provides information about impending collision
• Ex. Driving on the freeway reading a book noticing a car is coming up
- role of vision in balance vision - a proprioceptive sense (e.g. sense of balance)
• Lee’s swinging room
3rd exam
3rd exam
Timbre & Complexity
Complexity: refers to the number of pure tones combines together
Timbre - when two tones sound different even though they have the same loudness, pitch, and duration. (different musical instruments)
Pitch & frequency (Hz)
Increases in frequency = Increase in pitch
- Pitch - ranging from low to high, that is most closely associated with the frequency of a tone.
- Frequency - the number of times per second that the wave repeats itself. Measured by Hertz.
o Hertz (Hz) - The unit for designating the frequency of a tone. One Hertz equals one cycle per second.
Amplitude & loudness (db)
- Higher amplitudes sounds louder
- Amplitude: refers to the height of the waveform. Measured in terms of decibels (db)
- Loudness - Sound ranging from soft to loud. Loudness increases with increasing decibels.
- (dB) - A unit that indicates the presence of a tone relative to a reference pressure: dB = 20 log (p/po) where p is the pressure of the tone and po is the reference pressure
Equal loudness curves
The number of decibels that create the same perception of loudness at different frequencies.
Range in hearing
o 20 – 20,000 Hz
Fundamental frequency
the lowest frequency of a complex tone. aka the first harmonic. The tone’s other components, called higher harmonics, have frequencies that are multiples of the fundamental frequency
Harmonics
frequencies that are multiples of the fundamental frequency
Place theory
- the frequency of a sound is indicated by the place along the organ of corti at which nerve firing is highest.
- Traveling wave - vibration of the basilar membrane from the base of the membrane to its apex in the shape of a snapped rope.
Temporal theory
- pitch coded w/ respect to the rate of neural firing
- a 500 Hz tone causes hair to bend 500 Hz per second, which causes neurons to fire at 500 Hz
Phase locking
- Each of the fibers fire at the peak of the sine-wave stimulus
- Neurons always fire at the same point, or phase of the stimulus
- Firing of auditory neurons in synchrony with the phase of an auditory stimulus
Volley principle
- allows the brain to code frequencies above 1,000 Hz
- several neurons fire sequentially
Interaural Time difference (ITD)
Brain uses the difference in time in which a sound reaches both ears to determine the location of the sound source
o useful for frequencies below ~ 1300 Hz
Ineraural Intensity Difference (IID)
Brain uses the difference in loudness between the two ears to determine the location of the sound source
o useful for frequencies above ~1300
o High frequency sound do not bend around the head. A sound shadow forms on the other side, reducing loudness to that ear
Cone of confusion
points in space such that sound sources produce identical interaural time and intensity differences. Head movement helps.
Direct vs. Indirect sound
Direct - Directly from the sound to the ears. (outside)

Indirect - Reflected sound from a surface (a room’s walls)
Fusion effect
sounds from two different locations are perceived as one sound coming from a single location.
Precedence effect
when there is a delay of less than 50 ms the listener hears the sound that reaches his ears first.
Auditory scene vs Auditory scene analysis
Auditory scene – all of the sounds in the environment
Auditory scene analysis – how we separate the sounds into separate perceptions
Architectural acoustics
The study of how sounds are reflected in rooms.
Visual capture
You hear the sounds coming from its seen location, not where it is produced.
- Ex. You perceive the sound coming from the actors mouth, not the speakers
Basic components of music
A. Consonance / Dissonance - consonant - notes that sound pleasing when played together. dissonant - notes that sound unpleasant when played together

B. Note – the musical sound of a distinct frequency is known as a note (e.g., the note A = 440 Hz). Pitch indicates how high or low a note sounds.

C. Chord - multiple notes occurring simultaneously in time. Major chords (happy) and
Minor chords (sad);

D. Rhythm - the temporal relationship among sounds. Rhythm refers specifically to the duration of each note or chord.

E. Melody - the combined effect of pitch and rhythm.

F. Melody schema – the representation of a familiar melody stored in memory.
Phonemes & phonetic features
Phoneme - The shortest segment of speech that, if changed, would change the meaning of a word. (37 English, 11 hawaiian)
Vocal tract (vowels & consonants)
- Vowels: an open vocal tract
- Consonants: a closed vocal tract
Place of articulation
refers to where the obstruction of the air stream occurs (e.g., “p” in put – front of mouth; “c” in couch – back of mouth)
Manner of Articulation
refers to how the air stream is obstructed (e.g., “p”, “b”, “f” all obstruct the air stream in the front of the mouth)
Voicing
the timing and degree that vocal chords vibrate (“da” vs. “ta”)
Voice onset time (VOT)
the time delay between the beginning of a sound and the beginning of the vibration of the vocal chords
- da is voiced (no gap), ta is not voiced (gap)
Broca’s aphasia
difficulty in speaking due to damage in Broca’s area (frontal lobe)
Wernicke’s aphasia
difficulty in understanding speech due to damage in Wernicke’s area (the temporal lobe)
Formants
vowels, represented by horizontal band of energy in a speech spectrogram.
Formant transition
the rapid shift in frequency before a formant (vowel)
Segmentation problem
the problem of perceptually breaking continuous speech stimulus into individual words (foreign languages)
Variability problem
sound is so variable that there is no simple correspondence between the acoustic signal and individual phonemes (Different people’s voices, whad’aya’doin’?)
Phonemic restoration effect
when listeners perceive a phoneme that isn’t even there that is covered up (white noise or a cough)
Categorical perception
we only perceive either “da” or “ta” across the whole range of VOT’s (da da da ta ta ta)
McGurk effect
Visual information also plays a big role of what we hear. (we perceive “da” when we see a tape of someone saying “ga” with the sound playing “ba”)
Last Test
Last Test
Hairy & Glabrous skin
hairy skin – covers most of the body
glabrous skin – hairless skin, no hair follicles, thicker than hairy skin (palms, soles of feet)
Dermis and Epidermis
Epidermis – outer most layer
• Composed largely of dead skin cells
• Langerhans cells here (immunological function)
• Melanin-related cells here
• Dead skin cells are pushed up from the basal sub-layer of the epidermis
Dermis
• Blood vessels here
• sensory nerve endings and fibers here
Mechanoreceptors
these receptors respond to mechanical stimulation of the skin
• RA (rapidly adapting receptors) – two types, but in general they
• Fire when the stimulus I applies or removed, but not inbetween
• SA (slowly adapting receptors) – two types, but in general they
• Continue to fire as long as the stimulus is applied
• Responds to skin stretching, fine details, smooth texture
Thermoreceptors
these receptors respond to specific temperature or changes in temperature
• Warm fibers – increase firing rate when temperature increases (30-50 C range; 86F – 122F)
• Cold fibers – increase firing rate when temperature decreases (20-45 C range; 68F – 113F)