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Background

Sensation: the immediate, basic components of a sense

experience

-

At the neutral level

Perception: Organization of sensation components into a

recognizable form, object, or event

Two main processes

Bottom up: initiated by the stimulus input

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Neutral process

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Sensation

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Data driven

-

Features of the stimulusàwhat we perceive

Top- down: Initiated by the prior expectations or belief

-

Perception

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Knowledge driven

-

What we knowà

what we expect to perceiveà

What we perceive

Background

Top down processing is most important when:

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We have strong expectations

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The situation is familiar

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The stimulus information is weak or ambiguous

Bottom up processing is most important when:

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The situation is unfamiliar (we have no relevant

knowledge)

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The stimulus is clear and unambiguous

With both processes… is

Transduction

Transduction

-

Process by which a sensory information turns

into neural information

Each sense has its own

transduction process

-

Breaks down information

-

ALWAYS uses neurons to relay information to the

brain

Steps of Transduction

1.

Every sense starts with a stimulus

-

Stimulus is always External and Physical (touch,

taste, see, hear, smell)

Physical Stimuli:

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Taste (gustation): Food Chemicals

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Vision: Photons of light

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Hearing (audition): sound waves

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Touch (somatosensation): pressure and

temperature

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Smell (olfaction): air chemicals

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Process differs for each sense

Your senses

1.

Taste (Gustation)

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Physical stimulus: food chemicals

-

Transduction: Chemicals dissolve in saliva, move

into the fungiform papillae, Papillae contain taste buds (neurons respond to

food chemicals, prefer one flavor and fire to one flavor)

-

Basic tastes: Sweet, Sour, Salty, bitter

(different receptor sights) added later is Umami taste

-

Individual differences in taste

a.

Supertasters

b.

Abundance of taste buds

c.

More sensitive to flavors

-

Perception of taste is influenced by other

factors:

1.

Expectations and beliefs (top down)

a.

Wine price experiment

2.

Smell (olfaction)

-

Sensory Interaction: The principle that one

sense may influence another, as when the smell of food influences its taste

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Physical stimulus: air chemicals or gasses

-

Chemicals dissolve in mucus lining of nostril

cavity

-

Detected by olfactory receptors

a.

Located on olfactory bulb

b.

Send signal to appropriate area of a brain

Many of our senses work together to “create” an experience

3.

Vision- if it looks good it tastes better (top

down Process)