Child Psychology: The Modern Science, 3e by Vasta, Haith, and Miller Paul J. Wellman Texas A&M University John Wiley and Sons, Inc. © 1999 PowerPoint  Presentation: Chapter 7 Sensory and Perceptual Development

© 1999 John Wiley and Sons, Inc. Sensation and Perception n Sensation refers to the detection of sensory information n Perception refers to interpretation of sensation –Perception implies organization and understanding of meaning of sensations n Attention refers to selective perception –Focus on certain stimuli while ignoring others

© 1999 John Wiley and Sons, Inc. Theories of Sensory-Perceptual Development n Environmental/learning: Emphasizes the role of experience in organizing complex perceptions from simple sensations n Ethology: Emphasizes the innate aspects of perception that allow a baby to understand the world n Cognitive-Developmental: Emphasizes the impact of knowledge on perception

© 1999 John Wiley and Sons, Inc. Sensory Capabilities of Babies n Pain: Babies react with cries and heart rate changes to skin damage (pin prick) n Touch: Sensitivity to touch can be demonstrated in the womb –Tactile stimuli elicit a variety of reflexes in the newborn (rooting, palmar reflexes) –Haptic perception refers to recognition of objects by touch n Smells elicit facial expressions in baby –Positive: Banana, strawberry –Negative: Rotten eggs, fish

© 1999 John Wiley and Sons, Inc. Sensory Capabilities of Babies n Taste: Various tastes will either elicit a facial expression or change the rate of sucking (e.g. sweet tastes) n Vestibular sensitivity: Sensory feedback from vestibular organs maintain balance and body posture –Posture can alter alertness in babies (More alert in vertical than horizontal) –Visual cues can outweigh vestibular cues

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 7.3 Testing Visual and Vestibular Cue Interactions As the wall moves toward the infant, the visual system signals movement, while the vestibular system does not. The infant falls backward, indicating dominance of visual cues. (Figure adapted with permission from “Infants’ Sensitivity to Optical Flow for Controlling Posture” by B.I. Bertenthal and D.L. Bai, 1989, Developmental Psychology, 25, p 939. Copyright © 1989 by the American Psychological Association)

© 1999 John Wiley and Sons, Inc. Sensory Capabilities of Babies n Hearing: A 28 week old fetus shows reactivity to sound (eyelids clamp) –Newborn babies show changes in sucking rate to mother versus a strange female Newborn can discriminate mother’s (but not father’s) voice from that of strangers –Newborns can discriminate languages French versus Russian –Newborns are better at hearing low frequencies than high frequencies Babies are soothed by low frequency sounds

© 1999 John Wiley and Sons, Inc. Visual Capacity of Babies n Newborn babies can differentiate light from dark n Newborn babies are sensitive to movement (mobiles) n Visual acuity refers to the clarity of visual images –The visual acuity of a newborn is equivalent to 20/400 to 20/800 –The neural circuits that govern visual accommodation (flexing of lens) are not functional in a newborn

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 7.5 Infants Prefer Visual Patterns (Figure adapted with permission from “The Origin of Form Perception” by R. Fantz, 1961, Scientific American, 204, p 72. Copyright © 1961 by the Scientific American).

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 7.6 Measurement of Infant Eye Movements

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig. 7.9 Infants Scan Facial Features Seven week old babies scan faces for certain features: High contrast borders Eyes

© 1999 John Wiley and Sons, Inc. Infant Depth Perception n Infants are able to perceive depth by 7 months of age: –Avoid crawling across the visual cliff –Show changes in heart rate when exposed to a sharp drop-off n Depth cues: –Pictorial cues include convergence, relative size, and interposition –Motion parallax: Objects that are closer to us show greater apparent movement than do further objects

© 1999 John Wiley and Sons, Inc. Visual Scanning Studies in Older Children n As children grow older, they become more efficient in their scanning –Asked to consider two images of a house and asked “are these the same or different?” n Older children are –More careful in gathering visual information –More flexible in their search strategies –Less likely to be distracted in their visual searches

© 1999 John Wiley and Sons, Inc.Vasta, 3e Fig Eye Movements in Older Children InefficientEfficient (Figure from E. Vurpillot, R. Castelo, and C. Renard, 1975,Année Psychologique, 75, Figure 2, pp Figure reprinted with permission of Presses Universitaires de France)

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