Psychology Chapter 6 May Drop Out Iii More Prone Acts

Chapter 6

6

SENSATION, PERCEPTION,

AND ACTION

LEARNING OBJECTIVES

After reading and studying the material in this chapter, the student should be able to

understand the following ideas/concepts.

6.1 PERSPECTIVES ON PERCEPTION

6.2 THE INFANT

• Describe the changes in visual capabilities from birth through the first year, and note the

visual preferences exhibited by infants.

6.3 THE CHILD

• Explain how perception and action work together in the development and refinement of

locomotor skills.

6.4 THE ADOLESCENT

• Document the changes in attention during the adolescent period and discuss the

6.5 THE ADULT

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• Describe typical changes in vision and hearing that occur over adulthood and indicate

CHAPTER OUTLINE

I Perspectives on Perception

A. Sensation and Perception Definitions

1. Cytomegalovirus (CMV) – when contracted in utero can cause blindness in babies

2. Sensation – process by which sensory information is detected and transmitted to

developmental science debate

B. Issues of Nature and Nurture

1. Constructivists

a. Perception constructed through learning over time (nurture side)

2. Nativist

a. Born equipped with innate capacities and maturational processes, allowing us

3. Current debate on nature-nurture of perception

a. Constructivist view long popular

c. Some declines in sensory and perceptual abilities in later life

Checking Mastery

1. How is perception different from sensation?

➢ Answer: Perception is the interpretation of the information that is detected by the

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2. What is the difference between how constructivists and nativists view sensation and

perception?

➢ Answer: Constructivists believe perception is constructed from our learning

3. In what way is Gibson’s ecological theory of perception distinct from the

constructivist and the nativist views of perception?

➢ Answer: Gibson’s theory considers how the organization of the environment

II The Infant

A. Historical Perspective

1. Williams James viewed infancy as a state of “blooming, buzzing confusion”

2. Modern theorists believe that infants have greater perceptual skills than anyone

suspected

B. Assessing Sensory and Perceptual Abilities

1. Habituation – learning to be bored (present same stimulus repeatedly)

a. With repeated presentations, infant gets used to a stimulus

2. Preferential looking – infants look longer at one of two stimuli

a. Preference may indicate discrimination or liking one better

C. Vision

1. Basic capacities

a. Newborn infants can detect brightness and can track slow-moving objects

b. Visual acuity – ability to perceive detail

i. Newborn visual acuity is poor (40 times worse than adult)

ii. Improves quickly to about 20/120 on standard eye chart by age one month

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2. Organizing the world of objects

a. Infants attracted to contour—amount of light/dark transitions

b. Infants attracted to dynamic (moving) vs. static objects

c. Infants prefer object of moderate complexity (e.g., checkerboard)

3. Face perception

i. Prefer mom’s face to stranger’s face

ii. Prefer information in upper visual field (“top–heavy pattern”)

iii. Can pick out mom’s face if they have also been exposed to her voice at the

4. Depth perception

a. Very young infants act defensively (blink) when objects move toward their

face

b. Size constancy – infant can recognize that object remains same size even

though the retinal size changes as object moves away (Exploration Box on

infants’ understanding of size constancy)

c. Visual cliff – device used to assess depth perception (Gibson and Walk, 1960)

i. One “shallow” side with checkerboard directly under glass and a “deep”

iv. Fear of drop-offs (and perhaps falling) due to experience in crawling

5. The infant as intuitive theorist

a. Infants look longer at “impossible” events involving a ball’s motion

i. Ball drops behind a screen and appears to be suspended in midair

b. Innately understand simple laws of physics (object entering right of screen

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D. Hearing

1. At least as important as vision, and we depend on it to communicate

2. Process of hearing begins when moving air molecules enter the ear and vibrate the

converted to signals that the brain interprets as sound

3. Basic capacities

a. Newborns hear better than they see

i. Are startled by loud noise and turn away

4. Speech perception

a. Can distinguish phonemes—basic speech sounds—very early in life

i. Can distinguish similar consonant sounds (pa and ba)

ii. Can detect difference between vowels a and i from second day after birth

iii. Can distinguish normal from deviant (rare) sounds

iv. By three months, can recognize phoneme spoken by different people

b. Biologically prepared to learn and speak any language as infants

i. By one year, begin to lose sensitivity to speech sounds irrelevant to native

language and begin to show increased sensitivity to speech sounds

E. The Chemical Senses: Taste and Smell

1. Taste buds mainly on tongue; sense not well understood but is the result of bud

response to chemical molecules

a. Are four basic tastes (sweet, bitter, sour, salt)

b. Can distinguish tastes (sweet, bitter, sour) at birth, and like sweet

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sugar

2. Olfaction (sense of smell) result of receptors in nasal passage

a. Well established at birth

i. Newborns react unpleasantly to vinegar and ammonia

F. The Somaesthetic Senses

1. All skin receptors (touch, hot-cold, pain) operating in some form at birth

2. Reflexive touch apparent at birth

3. Tactile sensitivity develops in a cephalocaudal direction

4. Newborns sensitive to warm and cold

5. Young babies respond to pain (e.g., needle prick)

a. Ethical reasons restrict ability to test infants by inflicting severe pain

b. Pain is responsive to learning

G. Influences on Early Perceptual Development

1. All senses are working to some extent by birth, and most perceptual abilities

emerge in the first few months

2. Early experience and the brain

a. Classic study by Hubel and Wiesel on kittens showed deprivation of vision

early can lead to permanent loss of vision

b. Better to discuss impact of early experience in terms of sensitive periods

(rather than critical periods)

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permanent deficit in some aspect of vision, one for recovery from damage)

c. Infants born with congenital cataracts—clouding of the lens—at risk for later

visual problems

i. The earlier the cataract is surgically corrected or removed (by 10 weeks is

optimal), the greater the chance for normal vision (delays can lead to

d. Normal hearing requires normal auditory experience

i. Children with significant hearing loss who have cochlear implants struggle

to understand signal input that is sent from implant to the brain

ii. Brain must learn how to interpret information

e. Maturation is not enough, as normal perceptual development requires normal

perceptual experience

3. The infant’s active role

a. Infants seek sensory experiences they need for development

4. Cultural variation

a. Little difference in basic sensory ability

b. Interpretation of sensory input can vary by culture

painting, draw humans like tadpoles or scribbles

Checking Mastery

1. Describe two procedures used by researchers to assess perceptual abilities of infants.

➢ Answer: Researchers may habituate an infant to a stimulus by repeatedly

2. During their first few months of life, what can infants see best?

➢ Answer: Infants see best those objects that are relatively close to their face

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3. What sorts of experiences are necessary to develop normal visual perception?

➢ Answer: Normal visual perception requires opportunities for visual stimulation as

III The Child

A. Locomotion – the coupling of perception and action

1. Gross motor skills

2. Motor skills and dynamic action

c. Grasping and reaching

B. Integrating Sensory Information

1. Sensory systems like vision and hearing seem to be interrelated early in life

2. Cross-modal perception – recognize through one sense something known through

another

3. Impressions from different senses “fused” in early life, thus infancy is not the

“blooming, buzzing confusion” described by James

C. Advances in Attention

1. Attention – focusing of perception and cognition

a. Attention of infant and young child often “caught” or “captured,” while that of

2. Longer attention span

a. Young children have shorter attention spans

3. More selective attention – deliberate concentration on one thing while ignoring

another

a. Two-year-olds begin to show ability to focus

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4. More systematic attention

a. With age, children better at systematic perceptual searches (e.g., more detailed

D. Problems of Attention

1. Attention deficit hyperactivity disorder (ADHD)

a. Commonly diagnosed developmental disorder with combination of three key

symptoms:

i. Inattention – child does not seem to listen, is easily distracted, has trouble

2. Developmental course

a. When symptoms are predominately hyperactivity/impulsivity condition may

reveal itself in infancy

b. Must take care to not mistake normal high levels of activity in preschoolers

with ADHD

3. Suspected causes

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a. No consistent evidence of brain damage or structural defect in brain in most

children with ADHD

4. Treatment

a. Many children given stimulants like methylphenidate (Ritalin)

i. Odd to give stimulant for overactivity but brains may be underaroused

ii. Drugs increase levels of dopamine and other neurotransmitters in frontal

lobe

b. Controversy in drug as treatment

i. Too many children who do not have ADHD given medication

ii. Children who could benefit from drug may not be getting it

iii. Need to carefully monitor prescriptions

Checking Mastery

1. How do children master the important skill of walking and once they do so, how does

this new skill affect their development in general?

➢ Answer: Children master walking by integrating perception with action. They use

2. Why is cross-modal perception important?

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➢ Answer: Cross-modal perception allows for more efficient and robust perceptual

3. What are three ways that attention improves during childhood?

IV The Adolescent

A. Attention

1. Adolescents vs. children

a. Adolescents better able to sustain attention (longer attention spans)

B. Hearing

1. Loud music (above 75 decibels) may leave listener with hearing loss

2. Most common outcome of noise exposure involves tinnitus – ringing sounds in

one or both ears

3. Teens recognize awareness of potential hearing loss from exposure to loud sounds

but do not view as a health concern for them

4. Education programs

a. Need to focus on danger of long-term exposure

c. Reduce stigma of wearing ear protection

C. Another Look at the Chemical Senses

1. Taste

a. Researchers may have found a new basic taste (in addition to sour, sweet,

salty, bitter) called umami—Japanese word that roughly translates as “savory”

or “brothy”

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c. Taste influenced by cognition

i. Taste what you expect to taste

2. Smell

a. Gender difference in adolescence with females more sensitive to a variety of

odors

i. Likely related to hormonal differences

Checking Mastery

1. What concerns might we have regarding hearing during the adolescent years?

➢ Answer: Adolescents are at risk for long-term hearing loss if they are regularly

2. What are two observations regarding the chemical senses during adolescence?

➢ Answer: Adolescents are more likely than children to show acquired tastes, that

V The Adult

A. Vision

1. Sensory and Perceptual Change

a. Usually gradual and minor, beginning in early adulthood

b. Raised sensory thresholds—threshold for detection of stimuli (e.g., hearing a

2. Basic pattern of change

a. Most people will not lose sight with age

c. One in four will have cataracts—clouding of lens

3. Process of vision

a. Light enters through cornea and passes through the pupil and lens before

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4. Changes in the pupil

a. Pupil becomes smaller

b. Slower to react, resulting in poor dark adaptation—process of eyes adapting to

darkness

5. Changes in the lens

a. Lens denser, less flexible, and yellows

b. Thickening lens leads to presbyopia—difficulty seeing close objects clearly

i. May compensate by moving object further from eye

6. Retinal changes

a. Age-related macular degeneration – damage to cells responsible for central

vision

i. Vision blurry and fades from central of field of vision

7. Attention and visual search

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a. Adults are better able to control their attention (e.g., attend to angry face if

told a threat may be present)

B. Hearing

1. Hearing impairment and old age

a. Hearing impairments three times as prevalent as visual impairments in older

2. Basic capacities

a. Most age-related problems occur in inner ear

i. Some degeneration of cochlear cells and neurons leading to the brain with

age

3. Speech perception

a. Older adults have more difficulty understanding conversations

C. Aging of the Chemical Senses

1. Taste

a. General decline in taste sensitivity

2. Smell

a. Ability to detect odors declines in old age

3. Taste loss related to loss of sense of smell and cognitive factors (e.g., ability to

remember and name what was tasted)

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D. Changes in the Somaesthetic Senses

1. Detection thresholds for touch increases and sensitivity is gradually lost from

E. The Adult in Perspective

1. Declines in vision and hearing most important and nearly universal

Checking Mastery

1. What are the most common eye problems experienced by older adults?

➢ Answer: Many older adults have trouble with changing light conditions as the

2. What is the greatest functional difficulty with hearing loss among older adults?

3. Which taste is best perceived across the life span (i.e., undergoes the least loss of

acuity)?

➢ Answer: It turns out that we always have a “sweet tooth”: Young infants (and

SUGGESTIONS FOR CLASS DISCUSSIONS OR PROJECTS: To develop critical thinking skills

and enhance learning with exercises that support the course learning objectives.

1. Sensory Perception: There are literally thousands of toys that claim to provide infants with

stimulation and enjoyment. Many of these toys are marketed as being of educational value to

2. Changes in Perceptual Abilities: Some people think older adults should not drive because of

changes in perceptual abilities and reaction time. As a group, they are cited more than younger

drivers for “failure to obey signs and signals,” “failure to yield right of way,” and “inattention.”

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3. Sensory Changes across the Lifespan: Sensory changes across the lifespan often contribute to

behavioral changes. Decreases in sensitivity to taste and smell may change cooking and eating

4. Technology and Hearing: Given teenagers’ fascination with music, the current popularity of

in-ear headphones, and the propensity for students to play music at potentially dangerous levels,

5. Vision Loss and Changes: In the past, old age meant significant loss of vision. As the result

of modern medicine, many age-related vision problems are now easily treated. To increase