Sensation And Perception Psychology Ch. 7

Front 1

What is sensation comprised of? How does it differ from perception?

Back 1

Sensation comprises a physiological and elementary psychological response, to physical stimuli. Sensation asseses a stimuli's objective qualities. Perception is a more complex associative process by which memory and thought apply meaningful, subjective interpretations to stimuli.

Front 2

What are the three components of sensation? Describe each in detail and how they contribute to the process of sensation.

Back 2

1. Physical stimulus (matter or energy) acts upon sense organs to initiate a sensory experience.
2. Physiological response: transduction of physical stimulus into electrical action potentials which are transmitted through sensory neurons to appropriate cortical regions.
3. Sensory Experience: subjective experience of physical stimulus or the elementary assesment of its qualities such as taste, volume, etc.

Front 3

How does the sensory experience of a stimuli differ from the actual physical stimuli?

Back 3

We experience a quality, such as "bitterness", from encountering caffeine molecules. Bitterness is not an empirical quality of the caffeine molecule; it is an elementary interpretation.

Front 4

What are the five elementary senses?
What are sensory receptors?

Back 4

Hearing, Taste, Sight, Touch, Smell
Specialized cells, concentrated in particular sense organs or spread throughout the body, which transduce specific changes in the physical environment (specific types of physical matter or energy) into electrical action potentials to facilitate a sensory experience.

Front 5

How are receptors for the five elementary senses organized? How does this differ between somatosenses like pain and senses like vision and hearing?

Back 5

They can be concentrated in one sense organ (specialized receptors which respond to chemicals in food localized to taste buds, or alterations of physical positition of cilia responding to sound waves in ear, for example) or spread throughout the body. (Pain)

Front 6

What are sensory neurons and areas? How are they related to sensory-specific pathways?

Back 6

Sensory neurons transmit information about physical stimuli via action potentials from sensory organs to specific sensory areas of the central nervous system.
Sensory specific pathways: each sense comprises specialized receptor cells which transduce specific types of physical stimuli into electrical energy (receptor potential). These receptors synapse with particular sensory neurons. These sensory neurons deliver this sensory specific information to specific areas of the brain, and synapse with neurons localized to these regions for elementary sensory, and higher perceptual experiences.

Front 7

Name each primary sensory area and provide its locus.

Back 7

Primary auditory area: temporal lobe near the primary somatosensory area.
Primary somatosensory area: across the parietal lobe.
Primary olfactory area: around the proximal temporal lobe
Gustatory: temporal lobe
Visual area: occipital lobe near the back of the head.

Front 8

How are the processing centers of stimuli of the spinal cord different from those of the brain?

Back 8

Spinal cord initiates unconscious reflexive response to stimuli. Any cortical stimulation involves some conscious processing.

Front 9

What is the difference between conscious and unconscious stimulus processing?

Back 9

Conscious-- you are aware of the stimulus. You can assess some quality of it. Any sensory experience, no matter how arbitrary, requires conscious awareness.
Unconscious: you can respond (physically) and thus experience a stimulus, without having been consciously aware of it.

Front 10

What is truly required for a conscious, sensory experience?
How does getting hit by a ball in your occiptal cortex illustrate this?

Back 10

Stimulation, via sensory-specific neural pathways, of primary sensory areas responsible for interpreting the stimulus. You can 'experience' a stimulus without it exisitng.
Eg. artificially stimulating visual cortex-- if you get hit by a dodgeball-- you'll "see" stars that do not exist.

Front 11

What is transduction?

Back 11

The process by which a receptor cell converts a physical stimulus (matter [chemical molecules] or energy [sound or light waves]) into electrical action potentials which travel up sensory neurons to central nervous system.

Front 12

Describe transduction in detail.
Key terms: receptor cell, receptor membrane, receptor potential

Back 12

1. Particular chemicals or electrically charged ions (physical matter) diffuse across membrance of receptor cell. The membrane becomes more permeable to these types of cells in the presence of sensory specific types of matter or energy.
2. The molecules induce an electro-chemical change between the intra and extracellular membrance of the receptor cell called receptor potential.
3. Receptor potentials trigger synapses with the dendrites of adjunct sensory neurons, producing action potentials which travel through sensory neurons to applicable cortical area.

Front 13

Which fundamental properties of the stimulus must be preserved through transduction? (Translation into electrical impulses).
What is this called?
Why? (Evolutionary perspective)

Back 13

Quantitative Properties: the amount or intensity of energy: volume of a sound, the brightness of a light, the temperature).
Qualitative: the specific type of matter or energy (objective differences: "red" vs "green", "sweet" vs "sour")
SENSORY CODING: the preservation, throughout transduction, of relevant qualities of the physical stimulus in a pattern of action potentials.
Sensory information is useless unless we can ascertain how hot something is or what something is. (Should we run away? Is it safe to eat? Is it my baby screaming for help? Etc)

Front 14

How are qualitative properties of a stimulus different from interpreations of a stimulus?

Back 14

Qualitative properties are objective. They refer to the unarguable amount or intensity of a stimulus.
Eg. 250 ml of water with 50g of sugar concentrated in it is objectively sweeter than 250 ml with 10 g of sugar concetrated in it. (Does not depend on experience, etc)
Interpretation is: "I prefer the 10g of sugar to the 50g because the latter is too sweet."

Front 15

What is sensory coding? How does it relate to qualitative/quantitative properties?

Back 15

The preservation or encoding of relevant properties of a physical stimulus (qualitative and quantitative properties) in a pattern of action potentials transmitted to brain.

Front 16

What is the difference between the elementary psychological response component of sensation and the quantitative properties of a stimulus?

Back 16

The former concerns a subjective sensory experience-- the sensed "qualities" are not empirically present in the stimulus.
Quantitative properties are objective measurements of the degree or intensity of a stimulus-- "sweetness" as a measure of the physical concentration of glucose molecules. This is not the same as the sensation of "sweetness", which is a product of the mind.

Front 17

How do patterns of action potentials code the quantitative properties of a stimulus?

Back 17

A more intense stimulus, that is, the stimulus (such as coffee) has more physical chemical molecules concentrated in it, induces a greater degree of depolarization (receptor potential) in the receptor cell, which initiates rapid firings of action potentials (fast rate of action potentials) in the sensory neuron, which the brain interprets indicative of a more intense stimulus.

Front 18

In general, which rate of action potentials does the brain interpret as indicative of a strong stimulus?

Back 18

A fast rate of action potentials (that is, many action potentials fire IN SEQUENCE, not one that is "faster")

Front 19

How does an intense stimulus affect a receptor cell to induce a faster action potential?

Back 19

The stronger a stimulus, the more physical molecules it contains, the more physical molecules it contains, the more bind to receptor sits on receptor molecules, thus altering (increasing permeability) of membrane, which allows a greater degree of depolarization, which induces faster rates of action potentials

Front 20

What is receptor potential?
After consummating receptor potential, what can the receptor cell do?

Back 20

Depolarization of a receptor cell induced by the interaction of physical stimulus molecules (often chemicals or ions) and binding sites on the receptors. (Chemicals affect permeability of receptor cell, which enables more chloride ions in, potassium out, producing receptor potential)
Initiate an action potential in the adjunct sensory neuron

Front 21

What does it mean to say that receptor cells are specialized?
Give a non-abstract example.

Back 21

Each receptor cell is specialized to a particular type or quality of the particular type of matter or energy applicable to that sense. Thus, each receptor cell, contains proteins in its membrane, which bind more effectively to some types of chemicals (matter) or energy (sound waves) than others.
Eg. Different receptor cells in the nose contain receptor sites which bind most effectively with particular chemical molecules which induce particular "smells" upon stimulating the primary olfactory area.

Front 22

How do sensory systems code qualitative information about a stimulus? (Bearing mind I have already described receptor specialization).

Back 22

Because each receptor cell is specialized to respond best to particular aspects of a physical stimulus, and because different sets of sensory neurons synapse with different receptor cells, qualitative variations about a stimulus are interpreted by the brain from ratios of activity across the different sets of sensory neurons that deliver impulses to the brain.

Front 23

Using the example of biting into an apple, describe the process of sensory coding for qualitative and quantitative properties.

Back 23

Bite into an apple: mastication releases chemical molecules such as glucose into mouth. Glucose binds to receptor sites of receptor molecules specialized to interpret 'sweet' qualities. (Sweet taste buds) The intensity of the stimulus (how sweet it is) depends upon the amount of glucose molecules which bind to, and depolarize (receptor potential) the receptor cells. If it is a very sweet apple, many glucose molecules will bind to receptor sites on the receptor cells, and will make membrane very permeable, thus allowing more Cl ions to diffuse across membrane, and a greater degree of depolarization. This causes a fast rate of action potentials up the adjunct sensory neurons which the brain interprets as indicative of an intensely sweet stimulus. That the stimulus is sweet and not sour is interpreted because the ratio of 'sweet' or glucose receptive receptor cells which induce action potentials in adjunct sensory neurons is greater than those which respond to other chemicals-- thus stimulating areas of the brain which will automatically interpret a stimulus as sweet.

Front 24

What, ultimately, is responsible for any interpretation of a stimulus?

Back 24

The brain! All action potentials are the same! "Sweetness" is NOT inherent in the stimulus; only CH2O is. "Sweetness" is not inherent in the sensory neurons; only electrical action potentials are. Sensory neurons are specialized in that they respond to, and relay information to, portions of the brain which are solely repsonsible for creating psychological experience of "sweetness".

Front 25

When does a stimulus become "sweet"?

Back 25

When the particular area of the primary gustatory cortical area, which interprets sweetness, and is thus served by sensory neurons responding to sweet receptors, is stimulated.

Front 26

What environmental conditions do sensory systems respond to in general?

Back 26

Change-- altered or different conditions or stimulus.
Sensory systems are oblivious to steady states. (Sensory habituation)

Front 27

What is sensory habituation?
When does sensory habituation occur? (Two instances)

Back 27

A change in sensitivity to a particular stimulus which comes about when the sensory systems have been either exposed to that stimulus for a length of time or not exposed to that stimulus for a length of time.

Front 28

Describe the correlation between the amount of stimulation by a particular stimulus and the sensory system's sensitivity to it.

Back 28

Sensory systems become less sensitive to stimuli which they have been repeatedly exposed to for long periods of time and more sensitive to those which they have been deprived of for a long period of time.

Front 29

How do the sensory receptors and brain mediate sensory habituation?

Back 29

Sensory receptors become less receptive to stimuli that they are repeatedly exposed to-- induce a lessened degree of receptor potential, which results in a slower rate of action potentials, which results in less stimulation of the cortical area. Interneurons of the brain which receive impulses from sensory neurons can also mediate sensory adaption.

Front 30

What is the evidence that the brain also plays a role in mediating sensory habituation?

Back 30

If you plug one nostril and expose your olfactory receptor cells to a bottle of perfume for a long period of time you will become less sensitive to the smell (notice it less). If you unplug the other nostril, exposing DIFFERENT receptor cells to the physical stimuli, you remain desensitized to it. Thus the cortical interneurons of the primary olfactory area play some role in mediating sensory adaption.

Front 31

What is the evolutionary advantage of sensory habituation?

Back 31

Our sensory and neural mechanisms evolved to enable us to live within a contant environment without responding intensely to the stimuli typically present in it. Our receptor cells, and adjunct cortical areas, are most responsive to changing states-- thus, a novel, and potentially dangerous or unusual stimuli, initiates a faster rate of action potentials in sensoru neurons adjunct to receptor cells which undergo a higher degree of depolarization which in turn stimulate the cortical area which perceives fast rate of AP as indicative of novel, intense stimuli.
We react to potential dangers; not same old stimuli.

Front 32

What are the ultimate (survival) functions of smell and taste?

Back 32

Warning (food aversion, poison) and attracting (mate selection, mother infant bonding, nutrition)

Front 33

Why are smell and taste the chemical senses?

Back 33

They respond to physical chemical stimuli (chemical molecules-- glucose, poisons, etc)

Front 34

Which senses have the greatest effect on our drives and emotions?

Back 34

Taste and smell (connections to limbic system and hypothalamus-- emotional memories, release of dopamine, [initiate a drive] the 'wanting' hormone)

Front 35

What are three characteristics of taste and smell as senses? (Not that they are chemical-- what can they DO and what are their functions?)

Back 35

-->Initiate a drive
-->Trigger an emotional memory
-->Warning and Attracting

Front 36

Describe the transduction of smell.

Back 36

Chemical molecules from physical stimulus enter nasal cavity and bind with protein receptor sites on 700 million receptor cells in nasal cavity. These molecules alter membrane (make more permeable) and facilitate receptor potential. Receptor potential induces action potentials in adjunct sensory neurons which stimulate corresponding portions of the olfactory cortex which generate psychological experience of "smell."

Front 37

Why is sensory coding evolutionarily essential?

Back 37

Sensory systems are useless unless they inform the brain specifically of how intense the stimulus is or what the stimulus is-- should we run? Is it safe to eat? WHAT EXACTLY ARE WE EXPERIENCING? Sensory coding enables this.

Front 38

How does transduction occur in the nasal cavity?

Back 38

Chemical molecules from physical stimulus enter nasal cavity and interact with receptor sites on receptor cells, changing the shape of the membrane so that it becomes more permeable to chloride ions, initiating receptor potential, which initiates an action potential in adjunct sensory neurons, which stimulates correspodning areas of olfactory cortex, which generates elementary "smell" sensation.

Front 39

How are quantitative properties of the physical stimulus coded (for smell)?

Back 39

The overall number of receptor cells which bind with chemicals from physical stimulus and trigger action potentials indicates the intensity of the stimulus. (The amount of physical matter-- the actual molecules-- concentrated in physical stimulus)

Front 40

How do olfactory receptor cells enable coding of qualitative differences?

Back 40

Different receptor cells are more responsive (have more protein receptor sites, responsive to a particular chemical, than others) to particular chemical molecules.

Front 41

What does every olfactory neuron terminate in? (Have axon terminus in)

Back 41

The olfactory bulb in the primary olfactory area of the temporal lobe.

Front 42

What is contained within the olfactory bulb?

Back 42

Many glomeruli

Front 43

Describe how specialized receptor cells, olfactory sensory neurons, and glomeruli mediate qualitative coding. Use a rotting banana as an example.

Back 43

Different olfactory receptor cells respond most effectively to different types of chemical molecules. A rotting banana emits a certain type of molecule specific to the state of rotting. This molecule will bind most effectively to a specific receptor cell. This receptor cell induces an action potential in a specific set of sensory neurons. These sensory neurons, which will be repeatedly stimulated, and the most powerfully stimulated, terminate in the olfactory bulb. Specifically, they terminate upon a particular glomerulus. This glomerulus is specific to this sensory neuron, iin turn specific to a receptor cell, specialized to respond most effectively to a particular chemical. Thus chemicals which are particular to a rotting banana bind with a particular receptor cell, which in turn induces AP in a particular sensory neuron which ultimately stimulates a glomerulus which, particular to this odor, transmits impulse to limbic system (memory) and hypothalamus (drives). The ratio of stimulation across differingly specialized glomeruli in the olfactory bulb indicates overall quality of odor.

Front 44

What type of information does sensory coding preserve?

Back 44

Relevant information-- the qualitative and quantitative properties (evolutionarily useful)

Front 45

Which portions of the brain do the glomeruli of the olfactory bulb send their impulses?

Back 45

The limbic system and the hypothalamus (EMOTIONS AND DRIVES! Emotional memories that is)

Front 46

What specifically indicates the quality and quantity (amount or intensity) of a smell?

Back 46

Quality: ratios of stimulation across glomeruli (originating from ratio of binding of receptor cells and thus action potentials in specific neurons)
Quantity: overall amount of stimulation of glomeruli

Front 47

Given that the limbic system and hypothalamus are subcortical structures, what sort of processing of information from the olfactory glomeruli do you think they facilitate?

Back 47

Unconscious reactions to smells-- eg. conditioned salivation response to the smell of one's favorite food, or an emotional memory triggered by a PARTICULAR smell (that is stimulation of a particular glomerulus)

Front 48

Where is the olfactory bulb located and which three other brain areas does it transmit information to?

Back 48

Primary olfactory cortex in temporal lobe
1. Subcortical structures limbic system and (2) hypothalamus
3. Frontal cortex

Front 49

Which structure must the glomerulus stimulate for conscious evaluation, experience of a smell?

Back 49

The frontal cortex

Front 50

At which point does sensation occur?

Back 50

Upon stimulation of the glomeruli in the olfactory bulb in the primary olfactory area. (NOT upon stimulation of the frontal cortex)

Front 51

What might the frontal cortex do in response to smell?

Back 51

Decide if it likes the smell, or decide what to do (planning) about the smell. Eg. I smell a chocolate cake. I'm going to walk over there and take some. (Generate plan)

Front 52

What are the two pathways for smell? (For physical molecules to access olfactory epithelium)

Back 52

1. Through the nose
2. Through the mouth-nasopharynx

Front 53

What is "true taste"?

Back 53

The sensation elicited by chemical molecules interacting only with taste receptors.

Front 54

What are the two components of "flavor"?

Back 54

1. True taste-- the sensation elicited by the taste buds
2. Latent olfactory sensation

Front 55

From where do we experience flavor as originating from?

Back 55

Only the mouth-- we cannot identify the nose as the locus of flavor.

Front 56

How does the jellybean experience indicate that smell plays a role in flavor?
(Sub-question hints)
1. What is a jellybean?
2. What is the difference between flavor and taste?

Back 56

A jellybean is sugar (glucose) and flavoring (compounds). If you eat a jellybean but plug your nose, you occlude access to the nasopharynx and the olfactory epithelium-- molecules cannot bind to receptor sites on olfactory receptors. Taste receptor molecules bind to glucose, and elicit a "sweet" sensation which comprises taste. However, without the specific flavor discriminating abilities of the olfactory receptor cells, we cannot distinguish between flavors. (Grape, banana, etc)
Taste is the elementary sensation: either "sweet", "sour", "salt" "unami" or "bitter".
Flavor is the complex interaction of these elementary "true tastes" and smell..

Front 57

What are the five TRUE tastes?

Back 57

Unami, salt, sweet, bitter, sour

Front 58

In general, which sex is more sensitive to smell, and what is the correlation between age and smell sensitivity?

Back 58

Women and more sensitive than men; smell sensitivity decreases with age.

Front 59

What are two pieces of substantiation for the prop: "smell sensitivity declines with age?"

Back 59

1. Old people with perfectly functional tastebuds complain that they can't taste their food (smell is a component of flavor)
2. Old people die of aphysixia because they can't smell smoke or poisons.

Front 60

What is an (olfactory) absolute threshold?
What is the correlation between absolute threshold and smell sensitivity?

Back 60

The minimum number of particles needed to bind to receptor sites to initiate receptor potential.
The higher your absolute the threshold, the lower your sensitivity-- the lower your absolute threshold, the higher your sensitivity

Front 61

What evidence supports the conslusion: women become more sensitized to odors that they are exposed to for prolonged period of time than men?

Back 61

Women's absolute thresholds declined to particular odorants after repeated exposure to that odorant.

Front 62

When are women most sensitive to smells?
What are three possible evolutionary functions of this heightened sensitivity?

Back 62

Reproductive years.
1. Helps to avoid toxic food (smaller concentrations of toxic molecules neccesary to induce re. potential in poison receptor): small concentrations of toxins which might not harm mom could harm fetus
2. Helps to select an unrelated mate
3. Mother-infant bonding directly after birth

Front 63

Evidence that people identfy one another by smell. (HINT T-shirt experiment!)

Back 63

Person A asked to sniff a shirt that his sibling had (unbenknowest to him) worn all day. Person A identified this as his sibling's shirt.
Parents could also identify which shirts their children had worn by their smell.

Front 64

Evidence that mothers learn to identify their baby by smell directly after birth.

Back 64

Mothers exposed to their baby for ten minutes after birth could identify them by smell alone from the other babies.

Front 65

How is human olfactory mother-infant recognition different than animal mother-infant recognition?

Back 65

Human recognition is not essential for bonding and may be a vestigial trait. Humans bond in other ways, like love. Animals require olfactory recognition to bond to their offspring. (Birds won't accept odd-smelling young)

Front 66

Two pieces of evidence suggesting that human babies are predisposed to identify their mother by smell.

Back 66

1. Babies who nursed at their mother, presented a cotton pad which she had worn, and one which another woman had worn, reliably turned head towards its mother's pad.
2. If a baby is presented a conditioned scent directly after birth, baby will reliably continue to turn to that scent. (Olfactory imprinting)

Front 67

In general, what is the relationship between smell and mate selection?

Back 67

Mice and humans "prefer" those who smell most different to them.

Front 68

Why are we likely to select a mate who smells most different than us?

Back 68

They are less likely to be genetically related-- recall that genes produce proteins produce glands produce particular odorants.

Front 69

What do differences in odor actually result from? What is the OTHER function of this complex?

Back 69

Major histocompatability complex-- also responsible for producing antibodies which enable immunity to certain diseases.

Front 70

Why, then, in absolute terms, with regard to MHC, is it advantageous to select a mate with a different smell?

Back 70

A mate with a different smell likely has different genes in their MHC. If the individual has different genes in MHC (determining odor) than they also have different genes determining antibodies for immunity. Thus, mating a different smelling mate also ensures that the offspring will possess genes coding for immunity from different diseases, increasing their evolutionary fitness.

Front 71

What then are two general reasons for selecting a different smelling mate?

Back 71

1. Less likely to be related (different odorant genes in MHC)
2. Because of (1), offspring will possess genes entailing immunity to different diseases.

Front 72

What do studies of humans regarding mate selection/olfactory similarity suggest?

Back 72

Although humans pledge to "prefer" scents originating from genetically different MHC to themselves, it is inconclusive as to whether or not this actually plays a role in mate SELECTION. (Can it contribute to real love?)
-->May be, like mother infant bonding, a vestigial trait

Front 73

What are pheremones? What are some functions of pheremonal communication?

Back 73

A chemical substance produced by an organism which initiates a specific behavior pattern in another organism of that species.
Attracting a mate, marking territory, regulating hormone production

Front 74

What are the conclusions regarding pheremonal communication in humans?

Back 74

Although humans possess glands which secrete a steroid chemical similar to animal hormones, there is no established chemical or odorant which induces a universal behavioral reponse.

Front 75

Why might animals require pheremonal communication for mating? Why are humans different?

Back 75

Animals only copulate at certain times-- females only ovulate at specific times-- need to communicate to males when a female is ovulating. Humans can reproduce anytime they want: female menstrual cycles are not coordinated with pheremones.

Front 76

What are five primary functions of smell? Give some evidence or examples.

Back 76

1. Detect subtle, possible dangerous CHANGES in the environment
-->humans are more sensitive to smoke than most smoke detectors
2. Contributes to flavor and thus specific food aversion learning
3. Connections to limbic system and hypothalamus: can initiate an emotional memory (mother infant bonding?) or activate a drive
4. Mate selection-- ensure he isn't related, and has different antibodies
5. Female reproductive functions: mother infant bonding, toxin sensitivity

Front 77

Where are taste receptors contained?
What is the ultimate function of taste?

Back 77

In the mouth
Determining what is good (attraction) and bad (warning) to eat

Front 78

Where are taste receptor cells contained? How does this differ from olfactory receptors?

Back 78

Inside taste buds. They are not directly connected to gustatory neurons as olfactory receptors are connected directly to olfactory neurons.

Front 79

Describe gustatory transduction.

Back 79

Chemical molecules dissolve in the mouth and bind to receptor cells in taste buds which respond most effectively to that particular chemical, initiating receptor potential within the cell, and an action potential in the adjunct gustatory neuron.

Front 80

What are the five primary tastes? What kind of experience are they?

Back 80

Sweet, sour, unami (protein), bitter, salt
-->Objective, elementary sensory experiences independent from subtle flavorings

Front 81

How is the primary gustatory cortex organized to respond to stimulation from gustatory neurons?

Back 81

Different regions of the cortex, if stimulated, will elicit a particular taste sensation. (Eg. one area, if stimulated, elicits "salt" sensation, another, if stimulated, elicits "sweet")
-->NB that THIS, the ultimate cortical stimulation, generates taste-- not the action potential, or the receptor cell

Front 82

Evidence for the role that the primary gustatory cortex plays in sensation.

Back 82

Damage to this area impedes taste sensation even if person eats something sweet, and glucose binds to receptors, and adjunct neurons stimulates cortical region which should elicit "sweet", sensation will not occur if region is damaged.

Front 83

Which tastes are "pleasant" to us?
Which tastes are "unpleasant"?

Back 83

Salt, sweet and unami
Bitter and sour

Front 84

What is the ultimate explanation for our inherent taste preferences?

Back 84

We are predisposed to enjoy the taste of foods which likely contain chemicals or molecules that are nutritionally beneficial to us.
We are predisposed to dislike the taste of foods which likely contain toxins or poisons that are harmful to us.

Front 85

Why does salt taste good?

Back 85

We are motivated, by the pleasantness of the taste of salt, to eat foods which contain sodium chloride, to maintain blood pressure. (Homeostasis)

Front 86

Why do sugar and unami taste goood

Back 86

We are motivated, by the pleasantness of these tastes, to eat foods which likely contain high levels of glucose-- the quickest form of energy, and essential for homeostasis of blood glucoe-- and foods which contain much protein-- essential for all life functions.

Front 87

Describe a pain receptor cell.

Back 87

The pain receptor cell is the pain sensory neuron-- the 'receptor' portion of the neuron comprise free nerve endings spread throughout skin, tissues and visceral organs.

Front 88

What are the two types of pain neurons? Describe each and the type of transmission it facilitates.

Back 88

C-fibers: unmyelinated, small diameter-- slow rate of action potentials.
A-Delta: myelinated, wide diameter, fast rate of action potentials.

Front 89

What do A-delta fibers respond to? Which 'wave' of pain is this?

Back 89

Pressure, immediate extremes of environmental changes (temperature) or sharp, localized pain (such as a beesting)
-->The first wave of pain which alerts the organism to harmful situation or stimulus

Front 90

What do C-fibers respond to? Which wave of pain is this?

Back 90

Prolonged, throbbing pain such as that accompanying damaged tissues or infected cells
-->The second wave of pain which reminds organism to rest or remedy injured tissue
Eg. the bee sting is the first wave of pain (A-Delta), the latent throbbing is C-fiber, reminding you to reapply baking soda or whatever

Front 91

What are the two pathways for pain?

Back 91

1. Into the spinal cord
2. Into the brainstem-- the amygdala-- and the cortex

Front 92

Which pain pathway initiates a reflexive response to pain? Which facilitates conscious experience of pain?

Back 92

The spinal pathway facilitates an immediate, unconscious reflexive response to pain-- a withdrawal.
The midbrain pathway, leading to the amygdala and terminating in the cortex, facilitates a conscious experience of pain involving input from the limbic system and prefrontal (planning) cortex

Front 93

Which pathway initiates a response more quickly?

Back 93

Unconscious spinal pathway

Front 94

What are the three components of pain experience? What actually determines which level of pain the organism experiences? (Hint-- like smell and flavor)

Back 94

1. Sensory Component: involves the primary somatosensory cortex
2. Elementary Emotional or Motivational component-- involves the limbic system and Amygdala
3. Secondary Emotional and Motivational component-- involves the prefrontal cortex

Experience of pain depends entirely on its corresponding brain area. (Eg if you have a damaged limbic system you won't experience pain as something 'harmful' or to be avoided [motivational componenet])

Front 95

Which pathway must pain take to elicit ANY of the three levels of pain experience? In other words, what distinguishes all three levels of pain experience, from the spinal pathway?

Back 95

The midbrain-amygdala-cortical pathway-- ALL THREE LEVELS OF PAIN entail conscious experience of pain

Front 96

Describe the first level of pain experience.
1. Which brain area does it involve?
2. What does it entail?

Back 96

1. Primary somatosensory cortex in parietal lobe
2. A) Experience the actual 'sensation' of pain, or experience pain as a sensation (end result of transduction)
2. Identify specific qualitative (which type of pain-- burn? Cold? Knife wound?) and quantitative (how intense is it) properties of pain
C) Locate bodily region from which pain originates

Front 97

Describe the elementary emotional or motivational component of pain.
1. Brain area
2. What it entails (two-- hint: think emotion and motivation)

Back 97

1. Limbic system
2. A) Identify pain as harmful or hurtful (emotional component-- the 'ouch' factor)
B) Identify pain, which is harmful, as something that one should avoid or attempt to remedy (motivates behaviors to reduce pain and prevent harm)

Front 98

Describe the third level of pain experience.
1. Brain area
2. What it entails

Back 98

Secondary emotional or motivational component
1. Involves prefrontal cortex (planning and deliberation; integrates information from limbic system [learning and memory])
2. A) Entails secondary emotional response to pain (worrying about pain)
B) Secondary motivational response-- developing or planning to avoid, in the future, situations which elicited pain (Diff. from primary response which is to respond immediately in the present to occurent harmful situation without worrying)

Front 99

What is the best evidence for this prop:
'Pain is mind over matter'
Support using example.

Back 99

The sensation of pain does not require physical stimulation-- that is, a physical source of pain-- of pain receptors.
Eg 'Phantom Limb' pain: people experience sensation of pain and localize it to a limb which has been amputated and is no longer present (no pain receptors exist for this limb) [First level of pain: somatosensory area)
-->Indicates that cortical areas can induce pain sensation independtly of external stimuli or pain receptors: the memory of the limb and its pain elicits pain sensation.

Front 100

Describe gate-control theory.
Where is the major gate?

Back 100

The degree of pain experience depends upon the ability of neural impulses of pain sensory neurons to penetrate a neural gate between the spinal cord and midbrain and thus stimulate cortical regions solely responsible for eliciting different experiences of pain.
Between the spinal cord and midbrain

Front 101

What does gate-control theory hold as responsible for determining the permeability of the central gate?

Back 101

Direct internal, or indirect external, conditions which stimulate pain inhibiting or pain enchancing neurons in the central nervous system (cortex) which either open (enhancing) or close (inhibiting) neural gate.

Front 102

Which neurons directly affect the degree of pain experience and how?

Back 102

Pain inhibiting or pain enhancing neurons originating from primary somatosensory area of parietal lobe. Pain-enahcning synapse with interneurons in gate and cause it to open (permitting greater synapse between peripheral pain sensory neurons and central pain interneurons). Pain inhibiting close gate.

Front 103

(A) Which conditions (2) commonly increase pain sensitivity, (B) how, and (C) why?

Back 103

(A) (General) Illness or (localized) injury to a specfic area
B) Immune system (via hormones) acts upon pain-enancing cortical neurons-- causing them to open gate, and increase pain sensitivity. Localized damage or injury entails damaged or infected cells which release chemicals that alter receptor sites of C and A-Delta fibers, causing them to respond to lesser degrees of stimulation (first component), and also induce central pain neurons to respond to decreased levels of stimulation by acting upon pain-enhancing neurons and induce them to open the gate, resulting in increased pain sensitivity
C) Increased (general) pain sensitivity during illness motivates the organism to rest and conserve energy. Localized pain sensitivity (given that upon activating somatosensory cortex, the organism can identify exact body location that is in pain/being harmed) motivates individual to rest specific limb in need of healing.

Front 104

In general, what effect do illness, and injury, have upon pain sensitivity?

Back 104

Illness increases overall pain sensitivity; localized injury increases pain sensitivity in that area (lowers absolute receptor threshold)

Front 105

Which area mediates pain reduction? Where is it located?

Back 105

Periaqueductal gray-- PAG-- in the midbrain (between spinal cord and cortex-- just like gate!)

Front 106

What does the periaqueductal gray mediate?

Back 106

Pain reduction

Front 107

How does the PAG reduce pain experience or sensitivity in the cortex? (Hint: where do PAG neurons terminate and what do they act upon?)

Back 107

Neurons of PAG terminate upon pain-inhibiting neurons within major pain gate, causing it to close, and reducing pain sensitivity. Neurons also terminate upon neurons of spinal cord-- reducing sensitivity to stimulation from particular sets of sensory neurons (such as those from the leg, when running from a bear, for example)

Front 108

What evidence supports the assumption that the PAG reduces pain?

Back 108

Stimulating PAG reduces chronic pain in humans

Front 109

Why do morphine and opiates reduce pain?

Back 109

They bind to specialized receptor sites of the PAG, inducing activity which in turn reduces pain by inhibiting neural transmission across the central gate

Front 110

What is an endorphin?

Back 110

A morphine like substance produced within the body

Front 111

Where are endorphins produced?
What do they do?

Back 111

The brain and spianl cord-- release controlled by the hypothalamus
They specifically act upon the PAG to reduce sensitivity to pain.

Front 112

In general, which external situations generate increased and decreased pain sensitivity?

Back 112

Decreased sensitivity to pain is a sympathetic response: dangerous or alarming situations cause brain to secrete endorphisn which act upon PAG which reduces pain, enabling organism to escape without worrying about pain.
Increased pain sensitivity is parasympaethic-- in a safe environment, we become more attuned to changes which may harm us.

Front 113

Using the example of your (Marla aerobic) sore muscles, explain why your leg hurts when you are studying, but would not hurt if you were running from a bear.

Back 113

My C fibers are more responsive to pain from injured tissue (when I move the injured tissue, and through that inducement of action potentials to create movement, thereby activate adjunct pain receptors) because my body wishes that I sit and rest and not move, because I can, because there is no immediate reason to move my limbs. If I were being chased by a bear, the need to move (and escape) would eclipse my secondary need to rest my legs (and not move). Therefore, my brain, capable of processing the danger of a physical stimulus (cognitive dimension of fear), would release endorphins, which act upon my periaqueductal gray, which in turn stimulates pain-inhibiting neurons, which close the central gate, and prevent sensory neurons from my injured leg, from synapsing with the secondary cortical neurons which, stimulating the somatosensory, limbic and prefrontal areas, actually ultimate the sensation of pain. This collectively comprises stress-induced analgesia.

Front 114

What is analgesia?

Back 114

Decreased sensitivity to pain.

Front 115

When is the brain likely to induce anagelsia? What is this called and what is its evolutionary function?

Back 115

In stressful situations in which the organism must either fight or flee.
Stress-induced analgesia
-->Evolutionarily beneficial to not feel pain in situations in which pain is a distraction that would decrease the organism's probability of surviving its encounter with the stressful stimulus.

Front 116

Which chemical is essential for mediating stress-induced analgesia? Which structure ultimately produces, and which does it ultimately affect?

Back 116

Endorphins-- the brain (specifically the thalamus) produces, the hypothalamus secretes, and the hormone acts upon the periaqueductal gray.

Front 117

Which experiment substantiates the claim: Endorphins are essential for stress-induced analgesia?

Back 117

Two groups of students were subjected to a stressful situation: a math test.
Group A received endorphin blockers: thus, endorphins, produced by brain, could not bind to receptor sites on the periaqueductal gray
Group B did not
Group A did not experience analgesia
Group B did

Front 118

Given that endorphins are produced by the brain, what is ultimately, as usual, responsible for that which we experience?

Back 118

The brain-- not the environment, the neurons, the receptors-- the brain.

Front 119

How do endorphins facilitate stress-induced analgesia?

Back 119

Bind to specialized receptor sites on PAG and induce activity there which stimulates pain-inhibiting neurons which close major pain gate.

Front 120

What does the placebo effect indicate about stress-reduced analgesia?

Back 120

Placebos contain no active substance, but subjects are told that it contains endorphins (a known pain reducer). Thus the subject expects a decrease in pain sensitivity, and reduction in pain.
This belief in the reduction of pain, causes the brain to release endorphins which actually reduces pain by acting upon the PAG.

Front 121

Provide experimental evidence for belief-induced analgesia.
(Describe properly: hypothesis, variables, etc)

Back 121

Hypothesis: belief can induce analgesia by causing brain to release endorphins
Experimental conditions: two groups of people are given placebos, but told that they are painkillers (belief in pain-reduction)
Dependent variable: analgesia
Independent variable: ability of PAG to bind with endorphin molecules
Control: Group B, believing that they were receiving a painkiller, in fact received endorphin blocking drugs

Group A: experienced reduced pain
Group B: did not experience reduced pain
Suggested that belief can actualize analgesia by stimulating endorphin production (endorphins ultimately induce analgesia by binding to PAG)

Front 122

Two functions of hearing

Back 122

Alerts us to attractive or dangerous stimuli which we cannot see (at night, or behind occluding objects)
Allows us to communicate with language

Front 123

What is hearing the primary sensory modality for?

Back 123

Language

Front 124

What are the two 'meanings' of sound? (HINT if a tree falls...)

Back 124

Sounds is a physical stimulus (energy-- sound waves/vibrations) and an elementary psychological experience (the noise in your head)

Front 125

Describe the physical sound stimulus-- what is it actually, and how is this different from what it originates from?
What does the physical sound stimulus require?

Back 125

Physical sound waves, or vibrations, which require a substance (air or water) through which to transmit, and which originates from, but is not (as a sound) a physical object.
Eg. Sonny is the object; the vibrations through the air of his bark is the 'sound' stimulus

Front 126

What are the two 'qualities' of a sound? Which physical characteristics do they correspond to?

Back 126

Its loudness (amplitude) and its frequency (pitch)
Correspond to the height of a sound wave (amplitude) and the rate of complete wave cycles (distance from one wave to another [frequency of sound wave])

Front 127

Describe the relationship between amplitude, the height of the sound wave, and its medium.
Use an example

Back 127

The higher a sound wave, the greater the amplitude, the louder the sound. The more pressure exerted upon the sound wave, by its ambient molecules, the shorter the wave, the lower the amplitude, the softer the sound.
Words spoken across a brick wall are difficult to hear because 'solid' molecules exert much pressure upon sound waves

Front 128

What is frequency determined by and what does it determine? (In terms of sensation)

Back 128

Freuqency corresponds to the rate of complete wave cycles or the distance between two waves. This determines the pitch of a sound.

Front 129

What measures amplitude and what measures pitch?

Back 129

Amplitude: decibels
Frequency or pitch: hertz

Front 130

What is a pure tone? How does it differ from natural sounds?

Back 130

A pure tone has a constant frequency or pitch-- real-life sounds, such as a rustling page, or a waterfall, consist of many differing wavelengths with varying frequencies and amplitudes

Front 131

What is a natural sound?

Back 131

A sound which occurs in nature

Front 132

Why is 'hearing' a sense of 'touch'?

Back 132

'Hearing', or transduction of sound waves, begins with vibrations or pressure of sound waves upon patches of skin

Front 133

What are the three parts of the ear?

Back 133

Outer, middle, inner

Front 134

What is the function of the outer ear? How does it carry out this function?

Back 134

To relay sound waves (vibrations) into middle ear while preserving relevant qualities of sound wave
Vibrations from sound source induce vibrations in air-filled outer ear. Vibrating air molecules induce vibrations upon tympanic membrane (eardrum) at distal end of outer ear

Front 135

What is the tympanic membrane? Where is it?
What is the medium of transport for sound waves in the outer ear?

Back 135

Eardrum-- outer ear
Air

Front 136

Where is the middle ear? What is the medium of transport? What is the function of the middle ear and how does it carry out this function?

Back 136

Behing the eardrum-- air. To sustain and intensify vibrations. Throbbing tympanic membrane causes air particles to vibrate which causes ossicle bones to vibrate which induces oval window (small membrane with 1/10 the surface area of the tympanic membrane) to vibrate-- oval window increases the magnitude of the sound waves so that it can transmit into fluid-filled inner ear

Front 137

Where are the ossicles?

Back 137

Middle ear

Front 138

What is the medium of transport in the inner ear?
What takes place in the inner ear?

Back 138

Fluid
Transduction

Front 139

At which stage does a sound wave become intensified? At which stage does transduction occur?

Back 139

In the middle ear-- oval window begins to vibrate
In the inner ear

Front 140

What is another name for the inner ear?

Back 140

Cochlea

Front 141

Describe the cochlea
-Inner duct
-Outer duct
-Oval and round window
-Tectorial membrane
-Basilar membrane
-Hair cells
-Cilia

Back 141

Cochlea comprises two fluid-filled ducts: outer duct which runs from oval window (end of middle ear) around inner duct to round window (another membrane). Outer duct abuts a fluid filled inner duct. The inner duct is lined with a flexible basilar membrane and filled with hair receptor cells. Cilia hairs project from the receptor cells and, upon vibrating, push against the rigid tectorial membrane.

Front 142

What are auditory receptor cells called, where are they (precisely) and how do they interpret sound waves?

Back 142

Hair cells within basilar membrane in the inner duct of the cochlea-- cilia protrusions vibrate and push against tympanic membrane; the alteration of the hairs induces receptor potential in hair cells, enabling action potentials in adjunct auditory neurons.

Front 143

In general, which type of molecules induce a "sour" sensation?

Back 143

Acids-- such as those in unripe fruit

Front 144

Which types of molecules induce a "bitter" sensations?

Back 144

Toxins or poisons-- such as those emitted by a rotting corpse

Front 145

Why do so many-- nearly every variety of toxic chemical-- taste bitter to us? Why does toxin A taste the same as Toxin B as Toxin C? Why do no poisons TASTE sweet?

Back 145

Because every receptor cell, localized to the bitter taste bud, contains receptor sites which can bind to any kind of toxin. Thus, any toxic substance, binds to the receptor cell, which induces an action potential in a gustatory neuron which terminates in the portion of the gustatory cortex which elicits the sensation of "bitterness".

Front 146

How has evolution predisposed us to respond effectively to different types of chemicals? Why is it evolutionarily beneficial?

Back 146

-->We can develop new receptor sites on our bitter receptor cells to bind to new poisons that we encounter
-->If a poison, which is harmful to us, binds to these receptor sites, it will ultimately induce an unpleasant sensation of bitterness which punishes having eaten a harmful substance, and discourages the organism from eating it again. (Food aversion learning)

Front 147

Why would it be evolutionarily stupid to avoid all bitter tasting foods?

Back 147

Most plants have developed high concentrations of toxic chemicals which taste bitter, are not neccesarily harmful, in order to prevent predation. Many plants that are nutritionally beneficial thus taste bitter because they have small concentrations of non-harmful toxic substances (like spinach). We need to learn to like or enjoy these foods to reap their nutritional benefits.

Front 148

How do children learn which foods are safe to eat and which are not?

Back 148

By observation. Because children are naturally more sensitive to toxic chemicals than adults, they cannot judge for themselves which foods are safe to eat. Thus, children learn by observing adults which foods are, ultimately, nutritional beneficial.

Front 149

What type of sense is pain? Where are pain receptor cells?

Back 149

A somatosense-- pain receptors are spread all throughout body (not localized to one region), and are within bodily tissues. (Thus, pain can be elicited from within, independent of external stimuli)

Front 150

Does pain always require external stimuli? Explain yourself.

Back 150

No. Pain receptors are within the bodily tissues and thus respond to internal conditions-- not only enviornmental ones.

Front 151

From where do we experience pain?

Back 151

From within-- we identfy the sensation as contingent upon our body, rather something without our body

Front 152

How is pain different from other senses?

Back 152

1. Pain is a somatosense
2. Pain receptors are spread throughout body
3. Pain receptors respond to conditions within body
4. We experience pain as originating from within our bodies

Front 153

How is pain similar to an emotional state?
(Two)

Back 153

Pain can overwhelm consciousness and our ability to think. Emotion versus reason.
Pain has a universally recognizable facial expression

Front 154

How is pain similar to a drive or motivational state?

Back 154

Pain motivates behaviors to end pain.
Pain or the memory of pain, encourages organism to avoid future situations which entailed pain (so, we are driven to AVOID situations which we anticipate to be painful, as we are driven to pursue objects which satisfy drives)
Pain may also accompany another drive-- eg. hunger pains specifically motivate the organism to eat

Front 155

What is the evolutionary advantage of pain?

Back 155

Pain alerts us to situations which are harmful. We feel pain when something, either external, or internal (tissue damage) is harming us. Pain motivates us to avoid (in the future) or remedy situations that harm us.

Front 156

What do people born without pain sensitivity generally die of?

Back 156

Tissue damage-- they cannot detect internal disorders because they do not feel pain.

Front 157

What is unique about pain receptor cells from all other senses?

Back 157

Pain receptor cells do not synapse with an adjunct neuron; they ARE the sensory neuron.

Front 158

Describe the process by which sound waves are relayed to the inner ear or cochlea, and the process of transduction.

Back 158

Transduction in the ear: physical sound waves become electrical action potentials
1. Sound waves emnate from sound object.
2. Sound waves enter outer ear. Air in the outer ear transmits sound waves as vibrations.
3. Sound waves reach tympanic membrane or eardrum and cause it to vibrate.
4. Throbbing tympanic membrane induces air molecules of middle ear to vibrate, inducing the ossicle bones to vibrate.
5. Ossicle bones transmit sound waves to the oval window membrane. Oval window membrane is 1/100 the surface area of the tympanic membrane: this increases the magnitude of the sound
6. The vibrating oval window induces the fluid-filled outer duct of the inner ear to vibrate in a wave-like motion. The wave-like motions of the outer duct induce the basilar membrane of the fluid-filled inner duct to move in a wave pattern.
7. Wave patterns of the basilar membrane push cilia hairs against the rigid tectorial membrane of the inner duct. The alteration of shape of the cilia hairs induces receptor potential in receptor hair cells in the basilar membrane which induces action potentials in the adjunct auditory neurons.

Front 159

What is the real purpose of the outer and middle ears?

Back 159

To relay sound waves into the inner ear where transduction actually occurs. (Transduction does not occur in outer or middle ear)

Front 160

What are the two types of deafness? On which grounds do they differ?

Back 160

Conduction deafness and sensatorial deafness. Differ on physiological basis and forms of treatment.

Front 161

What does conduction deafness result from? Why does it result in hearing loss? What treatment is there for it?

Back 161

Conduction deafness: ossicle bones in middle ear ossify-- they cannot vibrate, and cannot conduct sound waves (vibrations) to oval window at entrance to cochlea.
Thus, we cannot hear sound, because transduction cannot occur (in the cochlea) because the sound waves is not transmitted beyond the middle ear.
Treatment: a hearing aid which amplifies the sound so that bones in the face other than the ossicles vibrate and apply sound waves to the oval window.

Front 162

What does sensatorial deafness result from? Why does it result in deafness? What treatment exists for it?

Back 162

Damage to the cochlea, hair cells or basilar membrane-- any part of the inner ear which carries out transduction. (Sound waves are conducted to inner ear, but cannot be converted into electrical impulses, so cannot stimulate auditory neurons).
Treatment: a hearing aid which transduces (converts to electrical impulses) sound waves and artificially stimulates auditory neurons.

Front 163

What is traveling wave theory?

Back 163

That receptor cells of different portions of the basilar membrane respond best to different frequencies of sound wave and this is how frequency is encoded through transduction.

Front 164

According to traveling wave theory, which portions of the basilar membrane respond best to high frequency sounds, and which to low frequency?

Back 164

Proximal end, near the oval window of the cohlea, respond most effectively to high frequency sounds which actualize maximum wave height near the proximal end. Low frequency sounds, which actualize maximum wave amplitude near the distal end (away from oval window), affect most the receptor cells at the distal portion.

Front 165

Which two auditory phenomena does traveling wave theory explain?

Back 165

Asymmetry of auditory masking and the pattern of hearing loss with age.

Front 166

Why do high frequency sounds affect the proximal portion of the basilar membrane?

Back 166

High frequency sounds actualize their highest amplitude near the proximal end of the basilar membrane. Receptor cells are most sensitive to a wave at its maximum height.

Front 167

What is sound masking?

Back 167

The ability to hear one sound and drown out the other.

Front 168

Describe asymmetry of sound masking and how traveling wave theory explains it.

Back 168

Low frequency sounds tend to drown out high frequency sounds. For example an oboe will drown out a violin. This is because low frequency sounds affect a greater overall portion of the basilar membrane because they do not peak until the distal end, whereas high frequency sounds maximize at the proximal end and not sustain themselves as long as low-frequency sounds.

Front 169

Describe a typical pattern of hearing loss with age and how traveling wave theory explains it.

Back 169

We become less sensitive (able to detect) high frequency sounds as we grow older. (Hertz declines). This is because hair cells at the proximal end wear out more quickly than those at the distal end, because hair cells at the proximal end respond to all frequencies of sound, whereas those at the distal end respond only to low frequencies.

Front 170

Why do hair cells at the proximal end of the basilar membrane wear out more quickly than those at the distal end?

Back 170

They respond to all frequencies of sound wave whereas those at the distal end only ever intercept low frequency sounds.

Front 171

How is the primary auditory cortex organized to interpret variances of pitch?

Back 171

The primary auditory cortex is tonotopically organized: different sets of neurons in the auditory cortex are organized to respond to specific auditory neurons which in turn carry action potentials induced by particular receptor cells which, depending on locus on the basilar membrane, respond most effectively to either low or high frequency tones.

Front 172

In general, what is the arrangement of low-high frequency tonal detection in the primary auditory cortex?

Back 172

Neurons which respond to auditory neurons carrying APs of high-frequency sounds are near the front; low-frequency at the back.

Front 173

Which two factors affect an individual's overall tonotopic map?

Back 173

Heredity (genes-- nurtue) and environment/experience (nurtue).

Front 174

Describe how heredity and experience shape an individual's tonotopic map.

Back 174

Genes determine the overall layout of the tonotopic map. Experience and environment determines which areas become most developed, owing to an increased rate of neural activity there depending on which frequencies the individual most encounters.
(Analogy: genes determine the "country", following this, experience builds cities in some areas, and leaves others to rest.)

Front 175

In general, what does transduction, traveling wave theory and tonotopic organization explain?

Back 175

The sensation of sound-- the elementary psychological experience of a sound's objective qualities. (Not yet perception)

Front 176

Why is the ability to locate a sound source important to survival? Is it learned? Provide evidence.

Back 176

We need to tell whether or not that rustling in the bushes comes from the left or right-- it is unlearned and reflexive; thus we respond immediately and do not have to think about locating a sound source, enabling us to escape, react more quickly. Babies reflexively turn in the direction of a novel sound source.

Front 177

Why is location of sound a reflex?

Back 177

Neurons in either ear react more quickly to sound waves which reach it a milisecond before the other ear-- thus the brain receives auditory input from one ear's set of neurons before the other, and immediately interprets it as coming from that side of the body. Our reflexive response to sound enables us to react to a potentially threatening sound source without having to deliberate its location.

Front 178

What occurs during phonemic restoration? (What is it)

Back 178

The brain provides us with perceptions or experiences of sounds which are not empirically extant (in sound waves).

Front 179

What is a phoneme?

Back 179

An individual vowel or consonant sound which aggregates a word.

Front 180

Describe Warren's experimental findings on phoneme restoration.

Back 180

Warren ommitted a phoneme from the phrase "the state governors met to decide new legisl*ture" ("a" phoneme ommitted and replaced with a cough sound). He found that subjects asked to listen to this phrase insisted that they heard the "a" sound, even when they were told that the "a" sound had been ommitted. (Heard it distinctly as occuring with the cough).

Front 181

What determines phoneme restoration? Why were Warren's subjects able to "hear" the "a" sound?

Back 181

"Sensation" of the ommitted phoneme depends upon the context which surrounds it. The brain assumed, from its memory, and associations with the words which surrounded the missing phoneme, that the phoneme "a" existed, and filled in the gap.

Front 182

What did ommitting the word "eel" from a set of sentences indicate?

Back 182

If "eel" was ommitted from these sentences:
The eel was in the sea
The eel was on the orange
Subjects heard (for A) "eel", and "peel" for B.

Front 183

What is essential for audition of an ommitted phoneme?

Back 183

The phoneme must be ommitted in lieu of white noise (cannot be silence).
The "heard" phoneme depends entirely upon its semantic context: thus, the words preceding and following the ommitted phoneme elicit a false auditory memory.

Front 184

How can evolution account for phoneme restoration phenomena?

Back 184

In real life, we rearely hear complete, uninterrupted streams of auditory stimuli. It is evolutionarily advantageous to be able to:
A) Discern from which direction a sound originates
B) Discern exactly which type of sound it is
C) Be able to create logical, likely patterns of sound from chaotic barrages of stimuli
Our brain mechanisms evolved so that we could, using memory and experience, organize, categorize and make sense of natural cacaphony, and hopefully pick out bits of information which we perceive as being important to us or our survival.

Front 185

Explain the evolutionary advantages of phoneme restoration using that neat shark example you invented.

Back 185

If you are on a boat, and you are terrified of being eaten by a shark, and you have seen plenty of shark movies, and memorized shark dialogue, and all of a sudden, amidst the dissonant pitches and tones of the rocking boat and clanging sea, the lapping waves and screeching gulls, you discern the captain yelling a faint: "...going to be *rk tonight!" (Assuming the * has been covered by some background sound) you will likely restore the ommitted phoneme with "sha", forming "shark", based on the context surrounding it, and your fears of being eaten by a shark. (Warning system-- recall ultimate functions of hearing: to identify/locate dangerous or beneficial stimuli, and to communicate)

Front 186

How do our perceptual hearing abilities ultimate the functions of hearing?

Back 186

1. Ability to locate sounds-- ultimate function of identifying harmful or helpful stimuli
2. Auditory masking-- ability to tune out one sound in favor of another, and done more easily with low than high frequency sounds: spoken words have a lower frequency (under 4000 hertz) than most sounds (communication).
Phonemic Restoration: Communication and stimulus detection, ultimately, for surivial purposes-- we do not need to hear every stimulus perfectly to discern meaningful auditory patterns and we are predisposed to discern meangingful auditory patterns.

Front 187

How does assymmetry of sound masking contribute to communication via language? (Hint think of hertz of spoken English)

Back 187

Spoken language is under 4000 hertz, so it has a relatively low frequency. It is therefore likely that we will be able to tune out most ambient noise in favor of spoken english, which benefits communication.

Front 188

What is psychophysics?

Back 188

The study of the relation between a physical stimuli and the resultant psychological response. (To what extent is the response contingent upon the stimulus?)

Front 189

How does a psychophysicist measure the relationship between a physical stimulus and its subjective experience?

Back 189

By asking subjects to rate or quantify in exact terms the magnitude or intensity of their responses to physical stimuli.

Front 190

What is an absolute threshold? Why is it interesting to psychophysics?

Back 190

Absolute threshold: the lowest amount of stimulus detectable to the individual to elicit a sensory experience
-->Provides an empirical measure of the neccesary magnitude of a stimulus to entail a psychological response (basis for understanding relationships)

Front 191

In general, what is the correlation between age, stimulus sensitivity and absolute thresholds?

Back 191

Adults tend to have higher abolute thresholds, requiring a greater magntude of stimulus to elicit a response, entailing lesser sensitivity. Children tend to have lower absolute thresholds.

Front 192

What is the difference threshold? What is its pet name?

Back 192

The difference threshold is the degree to which two stimuli must differ in order to an indivudual to discern the difference.
Just noticable difference.

Front 193

What did Weber think the relationship between the JND and the physical stimulus was? What is Weber's Law?

Back 193

The JND occurs (that is, the subject can detect a difference) if the second stimulus is at least 1/30 different from the original stimulus.
The just noticable difference is a constant proportion to the original stimulus. (1/30 for weight, 1/100 for line measurements)

Front 194

What did Fechner state about the relationship between sensory magnitude and stimulus magnitude? What is Fechner's Law? What was a limit of Fechner's Law?

Back 194

There is a lawful relation between them:
The jnd can be measured in physical units, (eg grams or line distance) and represents a proportional sensory experience (our ability to discern between different weights, lines).
The magnitude of the sensory experience is directly proportional to the logarithims of the physical stimulus.
The logarithims, or ratio between perceived stimulus intensity, and actual stimulus intensity, were undetectable.

Front 195

How did Stevens' power law differ from Fechners? What did is posit as a constant for each sense?

Back 195

Posited a constant "power", or ratio of perceived magnitude between two senses.

Front 196

What is Stevens' Power Law?

Back 196

The magnitude of sensation is directly proportional to the magnitude of a physical stimulus, rasied to a constant power.

Front 197

What does a power law, or constant power ratio, do?

Back 197

It preserves the perceived difference of magnitude between two stimuli even in the face of changing environmental conditions, or as the overall intsensity increases or decreases.

Front 198

Apply the power law to a practical situation.

Back 198

If you are in a forest at twilight, you perceive an object closer to you as a more intense (greater magnitude) stimulus than an object farther away. This ratio is maintained (constant) owing to a power ratio between them, so, even as it darkens, and the physical stimuli change, their power ratio, and our perception of their differing magnitudes, remains constant.