presentation name files/psychology/feldman10_ppt_ch04...title presentation name author ric created...

UNDERSTANDING PSYCHOLOGY 10TH EDITION

By Robert Feldman

Powerpoint slides by Kimberly Foreman

Revised for 10th Ed by Cathleen Hunt

Copyright McGraw-Hill, Inc. 2011

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CHAPTER FOUR:

SENSATION AND PERCEPTION

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MODULE 10:

Sensing the World Around Us

What is sensation, and how do psychologists

study it?

What is the relationship between a physical

stimulus and the kinds of sensory responses

that result from it?

3


MODULE 10:


Sensation

› Activation of the sense organs by a source of

physical energy

Perception

› Sorting out, interpretation, analysis, and

integration of stimuli carried out by the sense

organs and brain 4


MODULE 10:


Stimulus

› Any passing source of physical energy that

produces a response in a sense organ

Psychophysics

› Study of the relationship between the physical

aspects of stimuli and our psychological

experience of them

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Absolute Thresholds:

Detecting What’s Out There Absolute Threshold

› Smallest intensity of a stimulus that must be present

for it to be detected

› As the strength of a stimulus increases, the likelihood

that it will be detected increases gradually.

› Technically, then, an absolute threshold is the

stimulus intensity that is detected 50% of the time.

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Difference Thresholds: Noticing Distinctions Between Stimuli

Difference Threshold

› Smallest level of added (or reduced) stimulation

required to sense that a change in stimulation has

occurred

Just noticeable difference

Weber’s law

Just noticeable difference is a constant proportion of the

intensity of an initial stimulus (e.g. weight 1:50)

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Sensory Adaptation:

Turning Down Our Responses

Adaptation

› An adjustment in sensory capacity after

prolonged exposure to unchanging stimuli

e.g. occurs when we become accustomed to a constant

stimulus and change our evaluation of it. Repeated

exposure to a stimulus results in an apparent decline in

sensitivity to it. (p. 102)

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MODULE 11: Vision:

Shedding Light on the Eye

What basic processes underlie the sense of

vision?

How do we see colors?

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MODULE 11: Vision:

Shedding Light on the Eye

Vision starts with light, the physical energy that

stimulates the eye. Light is a form of

electromagnetic radiation waves

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Illuminating the Structure of the Eye

Cornea

› Protects eye and refracts light

Pupil

› Opening depends on amount of light in

environment

Iris

› Colored part of eye

Lens

› Accommodation 13



Reaching the Retina

› Light is converted to electrical impulses for

transmission to the brain

Rods

Receptor cells sensitive to light

Cones

Cone-shaped, responsible for sharp focus and color

perception

Concentrated in the fovea

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Sending the Message from the Eye to the Brain

› Optic nerve: A bundle of ganglion axons that carry visual

information to the brain.

Ganglion cells

Blind spot

Optic chiasm

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Processing the Visual Message› Takes place in the visual cortex

of the brain

Feature detection

Video:

https://www.youtube.com/watch?v=7OyXsFQRH7g 16


https://www.youtube.com/watch?v=7OyXsFQRH7g






Color Vision and Color Blindness:

The Seven-Million-Color Spectrum

Explaining Color Vision

› 1- Trichromatic theory of color vision

Suggests that there are three kinds of cones in the

retina each of which responds primarily to a

specific range of wavelengths.

Blue-violet colors

Green colors

Yellow-red colors

Not successful at explaining afterimages

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Not successful at explaining afterimages

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Color Vision and Color Blindness:

The Seven-Million-Color Spectrum

Opponent-process theory of color vision

› Receptor cells are linked in pairs, working in

opposition to each other (On-Off)

Blue-yellow

Red-green

Black-white

Explains afterimages

Video:

https://www.youtube.com/watch?v=D4lOwBt4DhY20


https://www.youtube.com/watch?v=D4lOwBt4DhY





MODULE 12:

Hearing and the Other Senses

What role does the ear play in the senses of

sound, motion, and balance?

How do smell and taste function?

What are the skin senses, and how do they

relate to the experience of pain?

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The Ear

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Sensing Sound

Sound

› Movement of air molecules brought about by a

source of vibration

Eardrum

› Vibrates when sound waves hit it

› Middle ear

Hammer, anvil, stirrup

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Sensing Sound

Inner Ear

› Changes sound vibrations into a form in which

they can be transmitted to the brain

Cochlea

Filled with fluid and vibrates in response to sound

Basilar membrane

Dividing cochlea into an upper chamber and lower

chamber

Covered with hair cells, when bent by vibrations entering

the cochlea, transmit neural messages to the brain24


Sensing Sound

The Physical Aspects of Sound

› Frequency

Number of wave cycles that occur in a second

Pitch: is the characteristic that makes sound seem “high”

or “low.”

› Amplitude: is a feature of wave patterns that allows us to

distinguish between loud and soft sounds.

Spread between the up-and-down peaks and valleys of

air pressure in a sound wave as it travels through the

air

Decibels (25


Our sensitivity to different frequencies changes as we age.

For instance, as we get older, the range of frequencies we can detect

declines, particularly for highpitched sounds.

This is why high school students sometimes choose high-pitched ring

tones for their cell phones in settings where cell phone use is

forbidden: the ringing sound goes undetected by their aging teachers

Sensing Sound

Sorting Out Theories of Sound

› Place Theory of Hearing

States that different areas of the basilar membrane

respond to different frequencies

› Frequency Theory of Hearing

Suggests that the entire basilar membrane acts

like a microphone, vibrating as a whole in

response to a sound28


Sensing Sound

Vestibular System

› Semicircular canals

Main structure of vestibular system

Three tubes containing fluid that sloshes through

them when the head moves, signaling rotational or

angular movement to the brain

› Otoliths

Sense forward, backward, or up-and-down motion,

as well as the pull of gravity29


Smell

Olfaction

› Sense of smell is sparked when the molecules of

a substance enter the nasal passages

Olfactory cells

Pheromones

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Taste

Gustation

› Taste qualities

Sweet

Sour

Salty

Bitter

“Umami’”

› Taste Buds (10,000)

Supertasters

Nontasters

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The Skin Senses:Touch, Pressure, Temperature, and Pain

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Skin sensitivity in various

areas of the body.

The lower the average

threshold is, the more

sensitive a body part is.


Substance P : One explanation is that pain is an outcome of

cell injury; when a cell is damaged, regardless of the source of

damage, it releases a chemical called substance P that transmits

pain messages to the brain.

Gate-Control Theory of Pain

› Particular nerve receptors in the spinal cord lead

to specific areas of the brain related to pain

Acupuncture 33



Acupuncture

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Managing Pain

Medication

Nerve and brain stimulation

Light therapy

Hypnosis

Biofeedback and relaxation techniques

Surgery

Cognitive restructuring 35


Synesthesia: unusually dense neural linkages

between the different sensory areas of the

brain.

Multimodal perception

› Brain collects the information from the individual

sensory systems and integrates and coordinates it

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MODULE 13: Perceptual Organization:

Constructing Our View of the World

What principles underlie our organization of

the visual world and allow us to make sense

of our environment?

How are we able to perceive the world in

three dimensions when our retinas are

capable of sensing only two-dimensional

images?37


MODULE 13: Perceptual Organization:

Constructing Our View of the World

What clues do visual illusions give us about

our understanding of general perceptual

mechanisms?

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The Gestalt Laws of Organization

Series of principles that

focus on the ways we

organize bits and

pieces of information

into meaningful wholes

› Gestalts

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Top-Down and Bottom-Up

Processing

Top-Down Processing

› Perception is guided by higher-level knowledge, experience, expectations, and motivations

Bottom-Up Processing

› Consists of the progression of recognizing and processing information from individual components of a stimuli and moving to the perception of the whole

› (permits us to process the fundamental characteristics of stimuli)

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Top-Down Processing

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Depth Perception

Ability to view the world in three dimensions

and to perceive distance

› Largely due to the fact that we have two eyes

Binocular disparity

Monocular cues

Motion parallax

Relative size

Texture gradient

Linear perspective

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Perceptual Constancy

Phenomenon in which physical objects are

perceived as unvarying and consistent

despite changes in their appearance or in the

physical environment

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Motion Perception:

As the World Turns

Cues about perception of motion

› The movement of an object across the retina is

typically perceived relative to some stable,

unmoving background

› Movement of images across the retina

› We factor in information about our own head and

eye movements along with information about

changes in the retinal image

› Apparent movement 45


Perceptual Illusions: The

Deceptions of Perceptions

Visual Illusions

› Physical stimuli that

consistently produce

errors in perception

Muller-Lyer illusion

Insert Figures 5 and 6 of Module 13

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Culture and Perception

Cultural differences are

reflected in depth

perception

› Zulu vs. Westerner

perspectives

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Subliminal Perception

Perception of messages about which we

have no awareness

› Called priming

Written word

Sound

Smell

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Extrasensory Perception (ESP)

Perception that does not involve our known

senses

› Most psychologists reject the existence of ESP,

asserting that there is no sound documentation of

the phenomenon

› Psychological Bulletin

“Anomalous process of information transfer” or psi

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