Chapter 4: Physical Development: Body, Brain, and Perception Perceptual Development By Kati Tumaneng (for Drs. Cook & Cook)

Perceptual Development Nervous system relatively immature at birth. Despite this, even young infants are more capable than previously thought at organizing and using sensory information meaningfully.

Robert Fantz and Visual Preferences Experiments to determine if form perception was innate or learned. Baby chicks pecked at some shapes more than others. Chimpanzees fixated on some patterns longer than others.

Robert Fantz and Visual Preferences Preferential-looking technique – Used to test infants visual perception. If infants consistently look longer at some patterns than others, researchers infer they can see a difference between the two patterns. Newborns only 2-5 days old preferred a drawing of a face over a bull’s eye or newsprint, but preferred these detailed prints over colored discs. Parents Guide to Visual Development: needs.org/parenting/preschool/visual_child_development.htmlhttp:// needs.org/parenting/preschool/visual_child_development.html

Looking Chamber

Preferential-Looking Results

Robert Fantz and Visual Preferences Human Faces and Other Preferences Moving stimuli Outer contours or edges Sharp color contrasts Patterns with some detail or complexity Symmetrical patterns Curved patterns Patterns that resemble the human face

Face Stimuli Researchers showed these patterns one at a time to newborns who were only a few minutes old. Although they had yet to see their first real face, the newborns preferred to look at the pattern that most resembled the arrangement of the human face.

Infant Visual Fixation of Facial Patterns Tracking their eye movements, you can see that 1-month-old infants spend most of their time looking at external features of the face – mostly the chin and outer hairline. By 2 months, infants are now looking more at the internal features, especially the eyes and mouth.

Habituation-Dishabituation Research Habituation – The tendency of infants to reduce their response to stimuli that they are presented repeatedly. Dishabituation – The recovery or increase in infant’s response when a familiar stimulus is replaced by one that is novel. Habituation-dishabituation technique – Used to test infants perception. Infants are shown a stimulus repeatedly until they respond less (habituate) to it. Then a new stimulus in presented. Degree of dishabituation is moderately accurate predictor of intelligence for ages 1-8.

Habituation-Dishabituation Example This graph shows hypothetical data from work with a 4-month-old infant using the habituation–dishabituation technique. The infant shows habituation by looking less and less at a red circle that is presented repeatedly—but looking time increases (dishabituation) when novel forms or colors are presented.

Vision: Acuity, Color, and Depth How Clear is Their Sight? Measuring Infant Visual Acuity Visual Acuity – Ability to see fine detail Fantz “striped patterns” Acuity poor in first months but sufficient for infant’s tasks Reaches 20/20 by 6-12 months

Patterns used to test visual acuity in infants Researchers use the preferential-looking technique to determine which set of stripes infants differentiate from the plain gray square.

Vision: Acuity, Color, and Depth How Colorful is Their Sight? Color Vision in Infancy Preference for green, yellow, or red over grey Distinguish red from white but not blue, green, or yellow from white Color vision relatively mature by 6 months

Vision: Acuity, Color, and Depth How Deep is that Drop? Early Depth Perception Infants as young as two months can perceive depth on visual cliff, better developed by age of crawling Cues indicating depth Pictorial Cues Motion Parallax Binocular Disparity

Visual Cliff

Auditory Perception Auditory system functional several weeks before birth. By 6 months, capable of responding to broad range of sounds. Even so, still not completely mature. Facts on Infant Hearing Loss: ENT ENT

Auditory Perception Child-Directed Speech – Special singsong way that adults and older children talk to infants, speaking slowly, clearly, and with exaggerated intonation. Infants and young children may be more sensitive than adults to higher frequencies of sound. Infants able to locate sounds in their environment by turning their head or eyes in the direction of the sound source. Prefer voice of own mother to voices of unfamiliar females; not same for father’s voice.

Perception of Smell and Taste Babies can react to certain odors in manner similar to adults. Breast-fed newborns can recognize smell of mother. Can also show taste preferences immediately after birth.

Perception of Smell and Taste

Intermodal Perception The process of combining or integrating information across sensory modalities. Infants capable of detecting features that are invariant across sensory modalities without significant learning. Strength of intermodal perception also predictor of later cognitive functioning. Newborn’s Sensory System info:

Looking Chamber on Slide 5: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 156). Boston: Allyn and Bacon. Chart on Slide 6: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 157). Boston: Allyn and Bacon. Face Stimuli on Slide 8: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 158). Boston: Allyn and Bacon. Infant Fixation Pattern on Slide 9: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 159). Boston: Allyn and Bacon. Chart on Slide 11: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 160). Boston: Allyn and Bacon.

Patterns on Slide 13: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 161). Boston: Allyn and Bacon. Picture on Slide 16: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 162). Boston: Allyn and Bacon. Picture on Slide 17: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 163). Boston: Allyn and Bacon. Picture on Slide 20: from Cook, J. L., & Cook, G. (2005). Child development: Principles and perspectives (1st ed.) (p. 164). Boston: Allyn and Bacon. All other images retrieved from Microsoft PowerPoint Clip Art.