Sensation And Perception Flashcards
(188 cards)
1
Q
In 1984, Ernst Weber published a book called ________, which was an…
A
De Tactu, an investigation of muscle sense
2
Q
Ernst Weber’s book introduced the notion of
A
Just noticeable difference (JND)
3
Q
In the mid 18th century, which psychophysics researcher discovered the relationship between physical stimuli and psychological responses to stimuli?
A
Gustav Fechner
4
Q
Gustav Fechner founded ____ ____, which was the mathematical expression of….
A
Weber’s law, Weber’s discovery about just noticeable differences
5
Q
Sir Francis Galton was one of the first researchers interested in _____ ______
A
Individual differences
6
Q
For six years, Galton maintained an ___ ___ in which he….
A
Anthropometric lab, measured the sensory abilities of nearly 10,000 people.
7
Q
Who founded gestalt psychology?
A
Max Wertheimer (1880-1943) - beginning with a visual illusion referred to as the phi phenomenon
8
Q
Briefly, Max Wertheimer’s studies led him to conclude that…
A
The experience of this visual illusion (phi phenomenon) has a wholeness about it that is different from the sum of its parts. He, like other Gestalt psychologists, believed that an analysis of experience into parts is not a valid way of studying our conscious experience.
9
Q
Psychophysics is concerned with
A
Measuring relationship between physical stimuli and psychological responses to the stimuli.
10
Q
One of the most important concepts to understand in sensory perception is the concept of
A
Threshold
11
Q
What are the two main types of threshold
A
Absolute and difference
12
Q
Absolute threshold is
A
The minimum of stimulus energy that is needed to activate the sensory system
13
Q
The amount of stimulus an individual can perceive is known as the
A
Absolute threshold
14
Q
Another word for threshold is
A
Limen - for instance, SUBliminal perception refers to perception of stimuli below a threshold - in this case, below the threshold of conscious awareness
15
Q
Difference threshold
A
How different two stimuli (in magnitude) must be before they are perceived to be different.
16
Q
What is an example of finding the difference threshold, and include the equation
A
Compare a standard stimulus to the comparison stimulus, which is different from the value of the standard stimulus. The subject’s task is to adjust the weight of the comparison stimulus’s weight until it matches that of the standard stimulus. After repeated trials, the differences between the weight of the standard stimulus and comparison stimulus are averaged - this value is the difference threshold.
17
Q
Difference thresholds and just noticeable differences measure the same thing, but in different __
A
Units. So, if a difference threshold is is 2kgs, this is also equal to 1 just noticeable difference. 4kgs would equal 2 just noticeable differences
18
Q
Sensation is
A
The activation of receptors in the various sensory organs
19
Q
Sensory receptors
A
Specialized forms of neutrons - the cells that make up the nervous system. Instead of receiving neurotransmitters from other cells, these receptor cells are stimulated by different kinds of energy - for example, the receptors in the eyes are triggered by light, whereas vibrations trigger receptors in the ears.
20
Q
Weber’s law states that
A
The change in stimulus intensity needed to produce a just noticeable difference divided by the stimulus intensity of the standard stimulus is a constant: ?I/I=K?
?I = change in intensity - so, 11 candles - 10 candles/ 10 candles = K (the constant, which is also known as Weber’s fraction or constant)
21
Q
In Weber’s law, the __K (constant), the better the ___.
A
Smaller, sensitivity
22
Q
Does Weber’s law for all data?
A
No. It does not fit data at very low and high intensities.
23
Q
According to Weber’s law, what’s important in producing a just noticeable difference is..:
A
not the absolute difference, but the ratio of them
24
Q
The amount of stimulus energy that needs to be added or subtracted from a stimulus for a person to say they notice a difference
A
Difference threshold
25
Fechner’s law
Expresses the relationship between the intensity of the sensation and the intensity of the stimulus
26
What is the purpose of Fechner’s law?
To relate the intensity of the stimulus to the intensity of the sensation
27
Fechner derived his law from Weber’s law and determined that
sensation increases more slowly as intensity increases
28
Steven’s power law
Also relates to the intensity of the stimulus and the intensity of the sensation
29
What are we really measuring when we measure thresholds in experiments?
We are really measuring what the person says they perceived that they sensed rather than what they actually sensed
30
Signal detection theory suggests that
other, non sensory factors influence what the subject says they sense.
31
What are the non sensory factors that can influence signal detection?
Experiences, expectations, motives, etc. For instance, a cautious person may want to be absolutely certain they heard a tone before responding “yes, I heard a tone”. On the other hand, another person might have only an inkling that they heard a tone before responding “yes”.
32
Response bias
The tendency of individuals to respond in a particular way due to nonsensory factors.
33
Unlike the earlier psychophysics, signal detection theory gives us a way to measure
both how well the subject can sense the stimulus (sensitivity) and response bias.
34
In a basic signal detection experiment, there are two experimenter controlled situations possible on a particular trial: either a stimulus is presented or it is not. Why are trials in which the stimulus is NOT presented called noise trials or catch trials?
Because even if a stimulus isn’t presented, your sensory systems are still excited by background noise, such as the random firings going on in the nervous system.
35
In signal detection lingo, the stimulus is called
A signal
36
In stimulus detection theory, each trial is either called a — or a —- trial
Noise or signal
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What is the participant asked to indicate on each trial in signal detection theory?
Whether or not a signal was present
38
Describe the following in terms of signal detection theory: hit, miss, false alarm, correct rejection (false negative)
You should know this
39
Habituation
Tendency of brain to stop attending to constant, unchanging information
40
Sensory adaptation
Sensory receptor cells become less responsive to an unchanging stimulus. For example, when the smell or garbage in the house is strong when you initially come into the house, but gradually becomes less noticeable.
41
Which of your senses does not adapt to a constant stimulus at the level of receptor cells?
Hearing
42
If you stare at something long enough, why doesn’t it disappear?
Even though the sensory receptors in the back of the eyes would adapt to and become less responsive to a constant visual stimulus, the eyes are never that still. There’s a constant movement of the eyes, tiny vibrations called SACCADES that people don’t notice constantly. However, the eyes do show sensory adaptation, so if the eyes didn’t move (which isn’t the case), the image would disappear.
43
The first step in all sensory information processing is __. Each sensory system has these to...
Receptors, react to sensory information
44
The second step in sensory information processing is __, which is...
Transduction, the translation of physical energy into neural impulses or action potentials
45
Once transduction occurs, the electrochemical energy is....
Sent to various projection areas in the brain along various neural pathways and can be processed by the nervous system
46
The cornea is the ...., which does what?
Clear, dome-like window in the front of your eye, which gathers and focuses the incoming light
47
The pupil, the hole in the ___, does what?
Iris, contracts in bright light and expands in dim light to let more light in.
48
The iris, the ___ part of the eye, has... and does...
Coloured, involuntary muscles and autonomic nerve fibres, which control the size of the pupil and therefore, the amount of light entering the eye.
49
The lens, which lies right behind the ___, does what
Iris, helps control the curvature of the light coming in and can focus near or distant objects on the retina
50
The retina is located where in the eye?
The back
51
The retina is like a ___ filled with ___ ___and ___ ___.
Screen, neural elements, blood vessels
52
The __ is the image detecting part of the eye
Retina
53
The duplicity or duplicity theory of vision states that
The retina contains two types of photoreceptors. The organization of the retinal cells makes light pass through intermediate sensory neurons before reaching and stimulating the photoreceptors.
54
There is a __ __ where the optic nerve leaves the __ and there are no ___ here.
Blind spot, eye, photoreceptors
55
Cones are used for what?
Colour vision and perceiving fine detail
56
Cones are most effective when? And what do they allow us to see?
In bright light, they allow us to see chromatic and achromatic colours
57
Rods function best in ___ ___ and allow perception of...
Reduced illumination, achromatic colours only
58
Rods have low sensitivity to __ and are not involved in __ ___
Detail, colour vision
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At the periphery of the retina, there are only __
Rods
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Are there more rods or cones in the eye?
Many more rods
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The middle section of the eye, the ___, contains only ___
Fovea, cones
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What happens as you move further away from the fovea?
The number of rods increases while the number of cones decreases
63
Because the further away you move from the fovea, the fewer cones there are, this means that visual __ is best in the ___, and the fovea is most sensitive in ___ ___ vision.
Acuity, fovea, normal daylight
64
The connection between the receptors (rods and cones) in the optic nerve is not __, there are several layers of ___ in between, called:
Direct, neurons, (1) horizontal, (2) amacrine, (3) bipolar cells and (4) ganglion cells
65
Rods and cones connect with __ cells, which connect with the ___ ___.
Bipolar, ganglion cells
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Ganglion cells group together to form the
Optic nerve
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Because there are many, many more receptors than ganglion cells, each ganglion cell has to..... this results in...
represent the combined activity of many rods and cones. This results in a loss of detail as information from the photoreceptors is combined.
68
The greater number of receptors that converge through the bipolar neurons into one ganglion cell the more...
difficult it becomes to make out the fine detail
69
On average, the number of cones converging onto individual ganglion cells is ___ than the number of rods converging onto individual ganglion cells. Therefore, cones have a...
smaller, greater sensitivity to fine detail than the rods do.
70
From the optic chiasm, the information goes to which places in the brain:
1. Lateral geniculate nucleus of the thalamus
2. The visual cortex in the occipital lobe
3. The superior colliculus
* remember the visual system is SUPERIOR, and so it is the superior colliculus that is involved, not the inferior colliculus
71
Hubel and Weisel’s work on the __ ___ earned them a Nobel prize in 1981
Visual cortex
72
Hubel and Wiesel found a ___ basis for what?
Neural, feature detection theory
73
Feature detection theory suggests that
Certain cells in the cortex are maximally sensitive for certain features of stimuli.
74
Hubel and Wiesel distinguished 3 types of cells. Name and define.
Simple - the responses of simple cells give information about the orientation and boundaries of an object
complex - give more advanced info about orientation, such as movement
hyper complex - give info about more abstract concepts, such as object shape
75
Hubel and weisel’s work was considered an amazing breakthrough because...
The idea that single cells could give info about such specific features was an amazing breakthrough
76
How did hubel and Wiesel measure cell responses?
Single cell recording - which involves placing a micro electrode in the cortex so sensitive that it could record responses of a single cell.
A microelectromechanical is so small that its tip can not be seen with an ordinary microscope.
77
Single cell recording is also sometimes called:
Recording from single nerve fibres
78
The rods have only one photopigment called
Rhodopsin
79
Dark adaptation is caused by
The regeneration of rhodopsin, the photopigment in the rods
80
Define lateral inhibition
When adjacent retinal cells inhibit one another; this sharpens and highlights borders between light and dark areas
81
Colour perception is related to the
Wavelength of light entering the eye
82
The human eye can see wavelengths from about ___ to __ nanometers
400 to 800
83
In order to understand colour perception, you need to understand the difference between what?
Additive and subtractive colour mixture
84
Subtractive colour mixture occurs when
We mix pigments. Like in kindergarten when you would mix blue and green to make yellow
85
Additive colour mixing has to do with
Lights - and since what our eyes see are lights, an understanding of additive colour mixture is important to understanding how we see colour
86
What are the primary colours of subtractive and additive mixtures?
Additive: blue, green, red
Subtractive: yellow, blue, red
87
In additive colour mixture, if you were to mix red and green lights, you would get
Yellow
88
If a stimulus does not emit its own light, we perceive it by...
Processing the light reflected off of it. An apple appears red because the wavelengths that appear red to us are reflected by the apple while all other wavelengths are absorbed.
89
What are the two basic theories of colour vision?
The Young-Helmholtz theory/trichromatic theory and Ewald Hering’s Opponent process theory
90
Describe the trichromatic theory
Suggests that the retina contains 3 different types of colour receptors (cones), which are differentially sensitive to different colours. One is maximally sensitive to red, one max sensitive to blue and one max sensitive to green, and all colours are produced by the combined stimulation of these receptors.
Light enters the eye, hits the retina and the three types of receptors are stimulated to varying degrees.
91
In the trichromatic theory, what determines the colour you see?
The ratio of activity in the receptors (cones)
92
The trichromatic theory demonstrated what?
That you could mix the three primary lights and produce all of the other colours of the spectrum
93
Describe Ewald Hering’s Opponent Process Theory of colour perception
Herring held that yellow must be one of the primary colours and that yellow was a basic colour along with red, blue and green. He further suggested that his four primaries (red, blue, green, yellow) were arranged in opposing pairs, so that one opponent process would signal the presence of red or green and another would signal the precedes if blue or yellow.
For instance, the colour red would excite a red-green cell, while green would inhibit a red-green cell. An implication of this is that since a cell’s response cannot both increase and decrease simultaneously, you could never have a reddish green. And if you think about it, it’s hard to imagine a reddish green. Herring also included an opposing pair to code the brightness, namely black-white.
94
Modern research, able to observe individual cells, suggests that which theory of colour perception is right?
The trichromatic theory
95
Modern research has shown what about Herring’s opponent process theory?
That it applies to other cells in the visual system, such as the cells in the lateral geniculate nucleus in the brain
96
What is an after image?
A visual sensation that appears after prolonged or intense exposure to a stimulus.
97
After images have been used to support Herring’s theory of colour vision, since...
The colour of the after image will be the “opposite” of the original colour. The concept of afterimages is what led Herring to his theory.
98
A good proportion of the explanation of depth perception was provided by who?
George Berkeley
99
What signals the three-dimensionality of objects?
The two dimensional image on the retina has certain characteristics that signal this three-dimensionality
100
What cues for depth did Berkeley coin?
Interposition (a.k.a overlap), relative size and linear perspective
101
Linear perspective
Refers to the convergence of parallel lines in the distance. In other words, lines which are actually parallel appear to converge on the horizon. Since you know that the lines done actually converge, you can use this cue in forming your impression of depth.
102
What three important cues are not included in Berkeley’s work?
Texture gradients (j.j. Gibson), motion parallax and binocular disparity (stereopsis)
103
Texture gradients refers to
The variations in perceived surface texture as a function of the distance from the observer. The more distant parts of a scene appear to have smaller, more densely packed elements. Furthermore, sudden changes in texture generally signal either a change in distance or change in direction (for example, a corner),
104
Motion parallax
When observer moves, objects in a stationary environment appear to move relative to the distance from the observer.
Ex) when in a car,fix gaze on an object about halfway between you and the horizon. You will notice that objects closer to you than your fixation point appear to move in the same direction you do. The perceived speed at which these objects appear to move also varies depending on how close the object is to your fixation point. The variation in apparent speed and motion is called motion parallax.
105
When an object rather than a perceiver moves, the motion of that object gives us cues about the relative depth of parts of the object. This is a special kind of ___ ___ called the ...
Motion parallax, the kinetic depth effect
106
Binocular disparity. This cue depends on...
the fact that the distance between the eyes provides us with two slightly disparate views of the world.
107
The degree of disparity between the retinal images of the eyes due to the slight differences in the horizontal position of each eye in the skull is called what?
Binocular parallax
108
As much as __% of the population can’t take advantage of __in depth perception. However, thanks to the other depth perception cues, they can still perceive depth.
10%
109
Stereopsis is the only depth cue that requires ___ ___ and is therefore called a ___ ___ ___.
Two eyes, binocular depth cue
110
Depth cues which require the use of only one eye are called
Monocular depth cues
111
Relative size is
The comparison of retinal size of object to actual size of objects gives cue to depth
112
Perceptual form is about how we...
abstract perceptual objects out of the array of blobs and contours appearing on our retina.
113
Perceptual objects exist only in our ___ and not...
Mind, in the retinal image
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The most important concepts to consider in form perception are
Figure and ground
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In terms of perception, the figure is the...
Integrated visual experience that stands out at the centre of attention.
The ground is simply the background against which the figure appears
116
Sometimes the figure ground can change, as in the famous __ __
Face-vase
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How is it that we can separate figure from ground, given that the retinal image is just a collection of blobs and contours? - __ psychologists have contributed a great deal to our understanding of this. What are the 5 laws that explain form perception?
Gestalt
The laws are: proximity, similarity, good continuation, closure and pragnanz
118
The law of proximity states that
Elements close together tend to be perceived as a unit.
In the figure, we don’t see 10 dots. We see a triangle and a square made from the dots. Pg 200 in book
119
The law of similarity states that
Elements that are similar to one neither tend to be grouped together.
120
The law of good continuation states that
Elements that appear to follow in the same direction (such as a straight line or a simple curve) tend to be grouped together. That is, there is a tendency to perceive continuous patterns in stimuli rather than abrupt changes. Some people argue that the phenomena of subjective contours may arise from this law.
Look at pg 200
121
Subjective contours have to do with
Perceiving contours, and therefore , shapes that are not present in the physical stimulus.
Page 200
122
The law of closure states that
We have a tendency to see complete figures as incomplete. It also states that when a white space is enclosed by a contour, it tends to be perceived as a figure.
123
The gestalt laws of organization operate together to create...
Taken together, this process is called..., which states that...
the most stable, consistent and simple figures possible within a given retinal array.
..the law of pragnanz, which encompasses the other laws and states that perceptual organization will always be as regular, simple and symmetrical as possible.
124
Gestalt psychologists have also considered his figure-ground configurations are represented in the brain. Wolfgang __ addresses this issue via the theory of ___, which suggests...
Kohler, isomorphism, which suggests that there is a one to one correspondence between the object in the perceptual field and the pattern of stimulation in the brain.
Isomorphism hasn’t faired well empirically but sometimes shows up on greexam
125
Modern theories of object recognition assume at least two major types of psychological processing:
Bottom up and top down
126
Bottom up processing
Object perception that responds directly to the components of incoming stimulus on the basis of fixed rules. Then it sums up the components to arrive at a whole pattern (such as in feature detection)
127
Top down processing
Object perception that is guided by conceptual processes such as memories and the expectations that allow the brain to recognize the whole object and then recognize the components
128
If we only did bottom up processing, we wouldn’t b very efficient at
Recognizing objects
129
If we only did top down processing, we would
See only what we expected to see
130
Name and describe the 5 types of ways to make a light look like it’s moving
1. Real motion: actually moving the light
2. Apparent motion (Phi): also called stroboscopic movement, this is when two or more stationary lights flicker in succession, they tend to be perceived as a single moving light
3. Induced motion: a stationary point of light appears to move when the background moves
4. Autokinetic effect: a stationary point of light when viewed in an otherwise totally dark room appears to move; probably caused by involuntary eye movements
5. Motion aftereffect- if a moving object is viewed for an extended period of time, it will appear to move in the opposite direction when the motion stops (e.g., a waterfall or stripes moving off to the right)
131
When discussing visual constancies, it is important to distinguish between proximal and distal stimuli. What are they?
Distal stimulus: the actual object or event out there in the world
Proximal stimulus: the information our sensory receptors receive about the object
132
In the case of vision, the proximal stimulus is the...
Image on the retina. The task of perception is to appropriately perceive the distal stimulus
133
Size constancy - page 205 for definitions of these. It has been shown that the __ of size constancy depends on perceived ___
Maintenance, distance
134
As it becomes harder to determine the distance of an object from the observer, the __ __ diminishes
Size constancy
135
Emmert’s law describes the
relationship between size constancy and apparent distance. It states that size constancy depends on apparent distance. The farther away an objects appears to be, the more the scaling device in the brain will compensate for its retinal size by enlarging our perception of the object
136
Shape constancy
The tendency for perceived shape of an object to remain constant despite variations in the shape of its retinal image.
137
Shape constancy scaling seems to have something to do with how we
Judge relative depth of the different parts of the stimulus based on its retinal image (e.g., opening a door example)
138
Lightness constancy
Refers to the fact that, despite changes in the amount of light falling onto an object (illumination), the apparent lightness of the object remains unchanged.
For example, even when the sun goes behind the clouds, the sail on a boat still appears white rather than gray. This occurs because the levels of illumination are the same for both the object and the background
139
Colour constancy
Refers to the fact that the perceived colour of an object does not change when we change the wavelength of light we see.
For example, when you put sunglasses on, you can still identify the colours of most objects you see.
140
A visual illusion is an __ __
Erroneous perception
141
What is a reversible figure illusion?
A reversible figure is a stimulus pattern in which two alternative, equally compelling perceptual organizations spontaneously oscillate (e.g., the Necker cube) on page 206
142
Over time we develop __ __ that make perception, or top down processing, easier
Perceptual sets
143
What are the two major methods for studying visual perception in infants? Define
Preferential looking: two diff stimuli presented side by side; of infant looks longer at one of them, it is inferred that the infant can perceive the difference between the two.
Habituation: a stimulus is presented to the infant, infant eventually stops looking at it; a different stimulus is presented, if the infant attends to it, it is inferred that the infant can tell the diff between old and new stimuli
144
Who designed the preferential looking method?
Fantz
145
At birth, infants are unable to discern...but can...
fine details, but can follow an object or light with their eyes when it is placed in the centre or their visual field
146
Newborns can perceive colour, simple ___ and __ __, and can even..
Figures, contrast, see in dim light
147
Who developed the visual cliff and when?
Eleanor Gibson and Richard Walk in early 1960s
148
What does the visual cliff assess?
Infant depth perception
149
Even at ___ age, infants will not attempt to cross the visual cliff
6 months
150
Sound is a
Wave of mechanical pressure
151
A sound wave can be described by specifying certain values, which are objective dimensions of sound. What are the two main ones?
Intensity and frequency
152
Frequency is the...and is measured in what units?
number of cycles per second, hertz
153
One hertz is equal to
One cycle per second
154
Frequency is inversely related to ___. That is, the...
Wavelength, the shorter the wavelength, the higher the frequency
155
Human sensitivity ranges from what to what hertz? What range is maximum sensitivity?
20-20,000hz, with max sensitivity at around 1000-3000hz, depending on age and hearing ability
156
Intensity is the...and it is measured in _
amplitude, or height of the air pressure wave
It is measured in bels (names after Alexander Graham Bell). However, since a bel is a relatively large unit relative to normal hearing, we usually talk in terms of decibels
157
The more decibels, the __ the sound is
Noisier
158
Sounds above __ decibels tend to be painful to human ear
140
159
Intensity is related to __
Loudness
160
What are 3 subjective dimensions of sound and their definitions?
Loudness - subjective experience is the intensity of the sound
Pitch - subjective experience of the frequency of the sound
Timbre - refers to the quality of the sound (related to the complexity of the sound wave or the mixture of the frequencies) for example, the same note on a piano sounds diff on clarinet
161
The neural basis of pitch perception has to do with the __ __, because it is the movement of the __ __ (sane word) was hat determines our pitch perception
Basilar membrane
162
According to place theory, proposed by __ and __...
Helmholtz and Young, each different pitch causes a different place of the basilar membrane to vibrate, in turn, causing different hair cells to bend
163
An alternative to place theory was called __ theory, which suggests that..
the basilar membrane vibrates as a whole, and that the rate of vibration equals the frequency of the stimulus. Further, this vibration rate is then directly translated into the appropriate number of neural impulses per second.
If a tone of 500hz causes the basilar membrane to vibrate 500 times per second, the vibrations would cause nerve fibres in the auditory nerve to fire at 500 impulses per second, so the pitch is determined by the frequency of the impulses travelling up the nerve.
164
What is the limit for frequency theory?
It cannot be applied to tones over 1000hz.
165
Weber and Bray modified the frequency theory by proposing what?
The volley principle, which states that Hugh rates of neural firing can be maintained if nerve fibres work together.
166
In the early 1960s, Von Belsen found out what about the movement of the basilar membrane?
That the movement is maximal at a different place among the basilar membrane for each different frequency (although the whole basilar membrane vibrates for any stimulus). High frequencies vibrate the membrane near the part of the cochlea close to the oval window; low frequencies maximally vibrate near the apex, or tip of the cochlea. This is sometimes called BEKSEY’S TRAVELLING WAVE THEORY.
167
What did Bekesy find about low frequency tones less than 400hz?
That low frequencies below 400hz maximally displaced a very broad part of the basilar membrane
168
The frequency theory is operative for tones up to about ___hz, place theory is operative for tones higher than __hz, and both mechanisms are operative between ___ and __ hz
500, 4000, 500 and 4000
169
Taste, like smell is a __ sense, because they both require receptors to have actual contact with the molecules that make up the stimulus
Chemical
170
Taste receptors at called
Papillae
171
The smell receptors are located where?
The upper nasal passage of the nose called the olfactory epithelium
172
Taste information travels to the taste center in the __, while smell information travels...
Thalamus, to the olfactory bulb in the brain
173
The sense of touch is actually quite complex and is generally described by 4 broad categories:
Pressure, pain, warmth, cold
174
There are at least __ receptors that receive tactile information, and they are:
Pacinian corpuscles (deep pressure)
Meissner corpuscles (touch)
Merkel discs (warmth)
Ruffin endings (warmth)
Free nerve endings
175
In terms of touch, transduction occurs in the receptors and information travels to the __ __ in the __ __ of the brain
Somatosenaory cortex, parietal lobe
176
What are the three concepts important to know for GRE in terms of touch perception? Name and describe
1. Two point thresholds - refers to the min distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli l
2. Physiological zero - a neutral temp perceived to be neither hot nor cold. Temp is judged relative to the physiological zero, or the temp of the skin. When we talk about feeling cold, it is likely because a stimuli has caused the skin temp to drop below physiological zero.
3. Gate theory of pain - the theory that there is a special hating mechanism in the spinal cord that turns pain signals on and off
177
What does the size of the two point threshold depend on?
The density of the nerves in the particular areas of the skin
178
Who developed the gate theory of pain?
Ronald Melzack and Patrick Wall
179
Proprioception is the general term for our sense of __ _\ and includes aspects of which two senses?
Bodily position, kinaesthetic and vestibular
180
The vestibular sense has to do with our
Sense of balance and our body position relative to gravity
181
The receptors for balance, the __ _, are located where?
Semicircular canals, located in the inner ear, above and behind the cochlea
182
The kinaesthetic sense has to do with
The awareness of body movement and position, specifically with muscle, tendon and joint position since the receptors are at or near them
183
___ __ proposed that selective attention acts as a __ between sensory stimuli and our ___ ___
Donald Broadbent, filter, processing systems
184
According to Broadbent, selective attention is a ___ __ __ process, meaning...
All or nothing, meaning that if we attend to something, we don’t attend to everything else. Evidence indicates this is not the case though.
185
The cocktail party phenomenon
An example of how you can attend to something you are interested in, while not totally ignoring background noise. You could be having a convo with one person when all of a sudden your ears perk up because someone half a room away from you mentions your name. Despite the fact that you were attending to the convo and not the background noise and STILL heard your name mentioned disproves Broadbent’s theory.
Thus, it seems that selective attention is more of a loudness control that dampens but does not completely block out ancillary stimuli.
186
In order to study selective attention in the lab; psychologists have used a technique called __ __, which is when..
Dichotic listening, when two ears are simultaneously presented with different messages. Generally, listeners are asked to shadow, that is, to repeat one of the messages as it is being presented. Using this method, it has been shown that ppl can attend to one message and dampen another one.
187
Yerkes-Dodson law
Performance is worst at extremely low or extremely Hugh levels of arousal, and optimal at some intermediate level.
188
Manning attention seems to depend, at least partially, on maintaining some kind of __
Arousal
