Sensation & Perception Flashcards
1
Q
Ernst Weber Published what book?
A
De Tactu–> investigation of muscle sense
2
Q
De Tactu by Weber introduced what notion?
A
Just noticeable difference in sensation–> one JND needs to be added/subtracted from stimulus for person to say he notices the difference
3
Q
Gustav Fechner discovered what relationship?
A
Relationship between physical stimuli + psych response to stimuli
4
Q
Francis Galton was interested in what field of study?
A
Individual differences. Measuring the sensory abilities of 10,000+ people
5
Q
Max Wertheimer founded what school of psychology? + believed what about studying conscious experience?
A
Gestalt psychology. An analysis of experience into parts is not a valid way of studying conscious experience
6
Q
Psychophysics is concerned with measuring what?
A
The relationship between physical stimuli + psych response to stimuli
7
Q
What are the two main types of thresholds in sensory perception?
A
Absolute threshold + difference threshold
8
Q
What is absolute threshold?
A
Minimum amount of stimulus that person can perceive + stimulus energy needed to activate a sensory system. E.G to taste, need 1 tsp of sugar dissolved in 2 gallons of water.
9
Q
Another word for threshold is what?
A
Limen. Hence the term sub-limen-al
10
Q
What is subliminal perception?
A
Perception of stimulus below the threshold of conscious awareness. Has little value in selling products.
11
Q
What is a difference threshold?
A
Refers to how different to stimuli must be in magnitude before a difference between them is perceived.
12
Q
How is difference threshold examined?
A
By comparing a standard stimulus to a comparison stimulus that is different in value.
13
Q
What is a just noticeable difference?
A
JND Measures the same thing as difference threshold but in diff units. It is the amount of change required to predict diff btw two stimuli.
14
Q
Weber’s law formulated by Fechner claims what?
A
What is important in producing a JND is not the absolute diff btw two stimuli, but the ratio of them
15
Q
What is Weber’s fraction?
A
S/S or I/I =K where K is the constant
16
Q
What does Fechner’s law express?
A
The relationship btw intensity of sensation + intensity of stimulus.
Sensation increases more slowly as intensity increases.
17
Q
Which scientist suggested that Fechner’s law might be incorrect?
A
S.S Stevens, who came up with Steven’s power law instead.
18
Q
What is signal detection theory?
A
Suggests that other, non-sensory factors influence what subjects say they sense. E.G experiences, motives, expectations play a role.
Cautious person wants to make sure they actually heard a tone VS paranoid person always being sure they heard it.
19
Q
Signal detection theory controls for which two factors?
A
1) How well the subjects can sense the stimulus
2) response bias due to non-sensory factors
20
Q
What happens in basic signal detection experiments?
A
1) two situations: stimulus presented/not presented
2) when not presented: noise trial, where sensory system still gets excited by random firings in nervous system in absence of stimulus
3) when presented: signal trial
21
Q
What are the four possible outcomes of signal detection experiments?
A
1) signal present- “yes it is”- Hit
2) signal present- “it’s not”- Miss
3) signal not present- “it is”- false alarm
4) signal not present- “it’s not”-correct negative
22
Q
What are receiver operating curves ROCs? Who refined these curves?
A
Used to graphically summarize a subject’s responses in a signal detection experiment. John A Swets refined their use.
23
Q
The first step in all sensory info processing is what?
A
Reception. Each sensory system has receptors to react to physical external energy.
24
Q
The second step in all sensory info processing is what?
A
Transduction. The translation of physical energy into neural impulses/action potentials.
25
The third step in all sensory info processing is what?
Projection. Electrochemical energy is sent to projection areas in the brain along neural pathways in order to be processed by nervous system.
26
Name the 5 structures of the eye + their function
Cornea-> clear, dome window. Gathers + focuses incoming light
Pupil->hole in iris. Contacts/expands to let light in/keep out
Iris->coloured part. Controls size of pupil + amount of light entering eye thru involuntary muscles
Lens-> behind iris. Control light curvature + focus near/far objects on retina
Retina->back of the eye. Detects images
27
Duplicity theory of vision states what?
Retina contains two types of photoreceptors. Light passes through sensory neurons before stimulating the photoreceptors.
28
What is the blind spot?
Where the optic nerve leaves the eye, and no photoreceptors exist.
29
What is the function of Cones + when is it most effective?
Most effective in bright light.
used for colour vision: chromatic + achromatic colours, as well as perceiving fine detail
30
What is the function of rods!+ when is it most effective?
Most effective in low illumination.
Not involved in colour vision + only perceive achromatic colours. Low sensitivity to detail.
31
There are many more --- then ---in human eye, except for the fovea at the centre that contains only ---. But there are more --- at the periphery.
More rods, less cones, fovea contains only cones so has best visual acuity + most sensitive to daylight vision. Rods at periphery
32
What do rods and cones connect with in the optic nerve?
Connect with several layers of neurons such as horizontal, amarcrine, bipolar, and ganglion cells. (HABG)
33
Describe why cones have greater sensitivity to detail?
Rods and cones connect with bipolar neurons--> connect to ganglion cells--> group to form optic nerve--> represent combine activity of many rods and cones--> loss of detail as info from photoreceptors is combined
34
On average, number of cones converged onto individual ganglion cells is ---than the number of rods.
Smaller. Which is why they have higher detail sensitivity
35
The image of stimulus on right side of visual field forms on the --- half of each eye's retina. The image on the ---side of visual field forms on the right half of retina.
Left, left
36
In the optic chiasm, do the fibres cross paths?
Yes, near the nose, the fibres from left eye go to right side of brain, the fibres from right eye go to left side of brain.
37
Do the fibres in the temporal halves of the retina cross paths?
No, the fibres near the temples don't cross paths. Fibres from left eye go to left side of brain, fibres from right eye go to right side of brain.
38
Info goes from optic chiasm to what parts in the brain?
Visual cortex in Occipital lobe--> memorize by saying you can C (see)
Lateral Geniculate nucleus of Thalamus--> memorize by saying (LAGAN)
Superior colliculus--> memorize by saying (superior border coli)
39
Which two scientists won the noble prize for feature detection theory?
Hubel and Wiesel
40
What does feature detection theory suggest?
By Hubel and Wiesel. Certain cells in cortex (simple, complex, hypercomplex) are sensitive to certain features of stimuli.
41
Describe simple, complex and hypercomplex cells
Simple--> info about orientation and boundaries of object
Complex--> advanced info about movement
hypercomplex-->abstract concepts i.e shape
42
How did hubel and Wiesel measure cell responses?
Through single cell recording. Involves placing a micro electrode in the cortex to record responses of each cell.
43
Illumination VS brightness?
Physical, objective measurement of light falling on surface VS subjective impression of intensity of light
44
Two factors involved in how we perceive brightness are:
Adaptation: adapting to dark environment but not being able to see at first due to the bleached out photopigment in your rods.
Simultaneous brightness contrast: target area appearing brighter when surrounded by darker stimulus due to lateral inhibition
45
What is rhodopsin?
The only photopigment in rods. Made up of vitamin A retinal + protein called opsin.
46
Describe the process of bleaching:
When molecule of rhodopsin (photopigment of rods) absorbs light, pigment decomposes into retinal and opsin. Takes time for pigment to regenerate.
47
What process sharpens and highlights the borders btw dark and light areas?
Lateral inhibition. It a cell is excited, it inhibits other cells, which won't fire as often, so area appears less bright.
48
What is colour perception related to?
To the wavelength of the light entering the eye. We can see wavelengths from 400-800 nanometers
49
Difference between additive and subtractive colour mixture:
Additive-> has to do with lights. Primary colours of blue green and red.
Subtractive -> when you mix pigments, such as blue and yellow to make green.
50
Describe Helmholtz's trichromatic theory:
Light enters the eye, hits the retina, then three types of receptors, each sensitive to one of the colours (green, red, blue) are stimulated to varying degrees. The ratio of activity determines the colour + mixing primaries gives you all of the spectrum.
51
Describe Hering's opponent process theory of colour vision:
We have 4 basic colours instead of three: red, blue, green, yellow + black and white. They are arranged in opposing pairs so that one opponent would signal the presence of the other. Since cell response can't go up and down simultaneously, we'd never have reddish green.
52
Who was right? Helmholtz or Hering?
Helmholtz.
53
What are afterimages?
Prove some parts of Hering's theory right.
It's the visual sensation appearing after prolonged exposure to stimulus.
E.G stare at red item, then look at white paper, you'll see green. Therefore, the colour of afterimage is opposite of original colour
54
Who came up with depth perception? And what did he assume?
George Berkeley. The 2D image on retina has certain cues that signal 3 dimensionality of actual object.
55
What are the 6 cues that signal depth perception?
Interposition->when one object overlaps with another, see one on front
relative size->as object gets further away, image on retina gets smaller
linear perspective->convergence of parallel lines in the distance
Texture gradients-> By JJ Gibson. Variations in texture as a function of distance from observer. The more far, the more densely packed.
motion parallax-> when observer moves, stationary objects move relative to distance from viewer
Binocular disparity-> each eye sees a slightly different scene, then brain combines them for full picture
56
What is Kinetic depth effect?
When the motion of an object gives us cues about the relative depth of its parts.
57
What is perception of form and what are its 2 components?
It is about how we abstract perceptual objects (e.g books) that exist only in our minds, from array of other things in our retina.
Includes figure (visual experience at the centre) and ground (the back ground of figure)
sometimes figure + ground can change. "Face case" example
58
What are the 5 gestalt laws of form perception and organization?
Proximity-> close elements are seen as a unit
similarity-> similar elements are grouped together
good continuation->same direction elements are grouped together
closure-> incomplete figures are seen as complete
pragnanz-> perceptual organization will always be regular, simple and symmetric.
59
What are subjective contours?
Perceiving contours and shapes that are not present in physical stimulus
60
What theory did Wolfgang Koehler suggest to address how figure-ground configurations are represented in the brain?
Isomorphism-> correspondence btw object in perceptual field and pattern of stimulation in the brain
61
What are the two types of psychological processing?
Bottom up processing-> Data driven. efficient at recognizing objects. Responds directly to stimulus based on fixed rules by summing up its components first to arrive at whole pattern
Top down processing->conceptually driven. See only what we expect to see. Recognizes whole object then the components based on memories and expectations
62
What are the five different ways to make light look like it's moving? A.K.A illusions of motion?
MAIA
Apparent motion (phi)-> two stationary lights flickering together. Looks like one single moving light
Induced motion->background moves, stationary light looks like it's moving
auto-kinetic effect-> dark room, stationary light seems to move because of eye movements
motion aftereffect->moving light seen for prolonged periods looks like it's moving the opposite direction when motion stops
63
Difference between proximal and distal stimuli?
Distal stimulus-> actual object/event in the world
Proximal stimulus-> info our sensory receptors receive about object/event. (Image on retina that most appropriate perceive distal
Stimulus)
64
What are the four major visual constancies?
Size constancy-> despite variations in size of object in retinal image, perceived size of object remains the same
shape constancy-> despite variations in shape of object in retinal image, perceived shape of object remains the same
lightness constancy-> despite variations in illumination, perceived lightness remains constant
colour constancy-> despite changes in spectrum of light, perceived colour remains constant
65
What does the visual angle of an object determine?
Determines the size of the image on the retina based on the size of the object and he distance between object + eye. But our perception of size remains constant
66
What does Emmert's law indicate?
Size constancy depends on apparent distance. The farther away the object the more your brain compensates for its retinal size by enlarging perception of the object.
67
Ames room and moon illusion are examples of which visual constancy?
Size constancy.
68
Name the five simple visual illusions?
Muller lyer->two horizontal lines are the same length
Hering-> two horizontal lines are the same length
Ponzo->two horizontal lines are straight + parallel
Wundt->two horizontal lines are straight + parallel
Poggendorff-> diagonal line on top and bottom are continuations
69
What is the necker cube?
Example of a reversible figure, where two alternative, equally compelling organizations move back and forth
70
What is preferential looking by Fantz?
Method used to study infant visual perception.
2 stimuli presented side by side. If baby looks at 1 longer, means he can tell the diff btw the 2, and likes the first one more
e.g complex and socially relevant stimuli like mom's face
71
What is habituation?
Another method to study infant visual perception
stimulus presented, infant eventually stops attending to it, a diff one is presented, if infant attends to it, it means he can tell the diff between the two
72
What can babies perceive at birth?
Follow object or light with eyes at the centre of their visual field, can perceive colour, simple figures, sharp contest and see in dim light.
can't discern fine details
73
What is Gibson and Walk's visual cliff?
Test of infant depth perception. Table has two parts, one seems much lower than the other like a cliff. Even at 6 months, infants won't attempt to cross.
74
What is sound?
Just a wave of mechanical pressure described by frequency and intensity
75
What are the objective vs dimensions of sound?
Frequency-> number of cycles per sec, measured in Hertz. The shorter the wavelength, the higher the frequency. People's sensitivity ranging from 20-20,000 HZ
intensity->amplitude of the sound wave, measure in decibels. The more decibels, the noisier the sound. Sound> 140 decibels is painful
76
What are the subjective dimensions of sound?
Pitch-> subjective experience of the frequency of sound. Distinguishes btw low and high tone
loudness->subjective experience of the intensity of sound.
Timber--> quality of the sound. Distinguishes between a note from piano vs violin
77
What happens in the outer ear?
Sound save reaches pinna (fleshy part outside)->
channels sound waves into auditory canal->
channels sound to eardrum (tympanic membrane)->
vibrates with sound waves, slow for low frequency, and fast for high Frequency sounds
78
What happens in the middle ear?
Uses three tiny bones called ossicles (hammer, anvil, stirrup) to transmit vibrations from eardrum to inner ear
79
What happens in the inner ear?
Oval window is the entrance to inner ear->
cochlea filled with saltwater fluid->
basilar membrane->
organ of Corti composed of thousands of hair cells->
receptors for hearing which bend due to vibrations of cochlea fluid->
and transfer electrical charge to cochlea and then the auditory nerve
80
The auditory nerve projects sound to which parts?
TIMS
1) superior olivary complex
2) inferior colliculus
3) medial geniculate nucleus in thalamus
4) temporal cortex
81
What is Helmholtz place theory?
Each different pitch causes different places on the basilar membrane to vibrate, these places of disturbance cause diff hair cells to bend. Operative for tones higher than 4,000 Hz
82
What is the frequency theory and to what situation CANT it be applied to?
Suggests that basilar membranes vibrates as a whole, and that the rate of vibration = frequency of stimulus. So pitch is determined by frequency of impulses traveling up the nerve.
Can't be applied to tones above 1000 Hz. Operative for lower than 500 HZ
83
What is Beksey's travelling wave theory?
Although whole basilar membrane vibrates for any stimulus, high frequencies maximally vibrate near the oval window, low frequencies maximally vibrate near the tip of cochlea. Anything less than 400Hz goes everywhere
84
Explain taste and smell mechanisms
Both require receptors to have actual contact with molecules of stimulus
Receptors for taste are called taste buds on papillae (little buds on tongue). Taste info goes to taste centre
Receptors for smell are in the olfactory epithelium (upper nasal passage). Smell info goes into olfactory bulb.
85
How can our sense of touch be described? (4 broad categories and 5 receptors)
Pressure (Pacinian corpuscles), pain (free nerve endings), warmth (Markel discs + Ruffini endings), cold
```
One additional:
Meissner corpuscles (touch)
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86
What are the three key concepts regarding touch perception?
Two point threshold-> minimum distance necessary btw two points of stimulation on the skin such that the two points will be felt as 2 distinct stimuli
physiological zero-> a neutral temperature perceived to be neither hot nor cold
Melzack and Wall's gate theory of pain-> there is a gating mechanism in the spinal chord that turns pain signals on and off
87
What is proprioception, and what sensual aspects does it include?
General term for our sense of bodily position. Includes
kinaesthetic sense (awareness of movement and position with muscles, joints etc)
vestibular sense (balance and position relative to gravity with receptors in the semicircular canals on our inner ear)
88
What is a staple name in selective attention, and what did he propose?
Donald broadbent. Proposed that selective attention acts as an all or nothing filter, where if you attend to something, it will be analyzed and everything unattended will be lost.
89
How does the cocktail party phenomenon prove Broadbent wrong?
Selective attention is not an all or nothing filter; it's more of a loudness control that dampens other stimuli but doesn't completely block them
90
How do scientists use dichotic listening to study selective attention?
Two ears are simultaneously presented with two different messages. Attend to one, dampen the other one.
91
Yerkes-Dodson law states what contrary phenomenon?
Performance is worst at extremely low or extremely high arousal levels. Optimal performance is achieved at intermediate level of arousal.
