Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Chapter 6
Perception
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Methods of Studying Infant Perception
• Habituation: Discrimination learning
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– “learning to be bored”
Preferential looking
– Study of visual acuity
Evoked potentials: recorded as child looks
Operant conditioning
– R+ of one stimulus in a pair
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Vision
• Present at birth
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– Detect changes in brightness
– Visually track moving objects
By 4 months can discriminate colors
Visual acuity at about 8 inches
Prefer contour, contrast, & movement
Prefer complex over simple patterns
Prefer human face over all
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Figure 6.1
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Vision 2
• Depth perception
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– Newborns appear to have size constancy
– The visual cliff: Gibson & Walk (1960)
• A crawler (7 mo) will not cross the cliff
• Can perceive the cliff by 2 months
• Fear of drop-off requires crawling
Infants as intuitive theorists: able to make
sense of the world
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Hearing and Speech
• Humans can hear well before birth
• Newborns discriminate sounds that differ in
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loudness, duration, direction, and pitch
Two-3 month olds distinguish phonemes
– Eimas (1985) “Ba & Pa” studies
Newborns prefer female/mother’s voice
Lose sensitivity to sounds not needed for
home language
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Taste and Smell
• Newborns can distinguish between sweet,
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bitter, and sour tastes
– Show a clear preference for sweet
– Facial expressions reflect taste
Cry and turn away from unpleasant smells
Breast-fed babies recognize mother’s smell
Mothers can identify their newborns by smell
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Touch, Temperature, and Pain
• Sense of touch(& motion) before birth
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– Useful for soothing a fussy baby
At birth sensitivity to warm and cold
Clearly sensitive to painful stimuli
Do babies require anesthesia for surgery?
– More harm from stress of pain
– Recommended for circumcisions
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Integrating Sensory Information
• Vision & touch, vision & hearing are
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interrelated within the first month
Cross-modal perception: previously seen
objects hidden a bag are identified by touch
Very early perceptual abilities are evidence
for “Nature”
Sensory system requires stimulation to
develop normally
– First 3-4 months considered critical
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
The development of Attention
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From infancy on
– Attention span increases
• More able to concentrate on a task
– Attention becomes more selective
• Able to ignore distractions
– More systematic perceptual searches
• To achieve goals & solve problems
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
The Adult
• Sensory and perceptual capacities decline
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– May begin in early adulthood
– Noticeable in the 40s
– Typical by age 65
– Gradual and minor in the normal person
– Compensation gradually increases
Sensory threshold: point at which the least
amount of a stimulus can be detected
– Increases with age
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Sensory/Perceptual Problems
• Vision by age 70: 9/10 wear corrective lenses
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– 1 in 4 will have cataracts
– Pupil less responsive to light
• Dim lighting is problematic
• Dark and glare adaptation difficult
Presbyopia: Middle age glasses
– thickening of the lens
Peripheral vision declines
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Hearing/Speech in Older Adults
• Most have at least mild hearing loss
• Presbycusis: loss of high-pitched sounds
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– More common and earlier in men
Some difficulty with speech perception
– May be cognitive or sensory
– Background noise a problem
Novel and complex tasks problematic
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 6
Other Senses in Older Adults
• Over 70 taste and smell thresholds increase
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– Many are not affected at all: mostly men
– Also affected by disease and medications
– Loss of enjoyment of food may cause
malnutrition in older adults
Less sensitive to touch and temperature
Less sensitive to mild but not sever pain