Perception, Motor Development, Learning, and Cognition in Infancy Chapter 5 Perception, Motor Development, Learning, and Cognition in Infancy

Perception Vision How do we study infant vision? Preferential-Looking Technique—Robert Fantz (1961) Habituation Visual Acuity and Infants contrast sensitivity cones on the fovea color vision

Visual acuity An infant’s visual acuity can be estimated by comparing how long the baby looks at a striped pattern such as this one versus a plain gray square of the same size and overall brightness. This simple test, first developed by researchers interested in visual development, is frequently used to diagnose early visual problems. (From Maurer & Maurer, 1988)

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. 7.5

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

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

Visual scanning The lines superimposed on these face pictures show where two babies fixated on the images. (a) A 1-month-old looked primarily at the outer contour of the face and head, with a few fixations of the eyes. (b) A 2-month-old fixated primarily on the internal features of the face, especially the eyes and mouth. (From Maurer & Salapatek, 1976)

Pattern Perception Subjective contour When you look at this figure, you no doubt see a square—what is called a subjective contour, because it does not actually exist on the page. Seven-month-olds also see the overall pattern here and detect the illusory square. (From Bertenthal, Campos, & Haith, 1980)

Object segregation Infants who see the display at the left of this figure (a) perceive it as two separate objects, a rod moving behind a block. After habituating to the display they look longer at two rod segments than at a single rod (b), indicating that they find the single rod familiar but the two segments novel. If they first see a display with no movement, they look equally long at the two test displays. This result reveals the importance of movement for object segregation. (From Kellman & Spelke, 1983)

Depth Perception Optical Expansion Apparent at 1 month of age Binocular Disparity Apparent at 4 months of age Monocular Depth Cues (Pictorial Cues) Apparent at 6–7 months of age

Auditory Perception Newborns show auditory localization at birth Taste and Smell Taste: Infants show preference for sweet tastes Smell: By 2 weeks of age, infants recognize their own mother’s breast milk and scent

Touch Infants explore with their hands, fingers, mouth, and tongue Oral exploration is prevalent during the first few months Around 4 months of age infants begin to explore by rubbing, fingering, probing, and banging objects

Motor Development Reflexes Motor Milestones Innate, fixed patterns of action that occur in response to particular stimuli Strong presence of reflexes at birth = healthy nervous system Grasping, Rooting, Sucking, Tonic Neck Reflex, stepping Some reflexes remain throughout life Coughing, Sneezing, Blinking, Withdrawing from pain Motor Milestones Reaching Self-locomotion Visual Cliff

The major milestones of motor development in infancy The average age and range of ages for achievement of each milestone are shown. Note that these age norms are based on research with healthy, well-nourished North American infants. (Adapted from Santrock, 1988)

6 Forms of Infant Learning Habituation Speed of habituation Speed and Duration of looking efficiency of Degree of novelty preference processing These 3 factors in infancy are related to IQs at 18 Perceptual Learning Differentiation—what elements are invariant or stable (happy tone of voice usually occurs with a happy face) Affordances—what actions can be performed with objects and situations (rattles are for shaking)

Classical Conditioning Visual Expectancy Infants form expectations for future events based on past experiences Infants can anticipate simple sequences Classical Conditioning An Example Unconditioned Stimulus—insertion of nipple into infant’s mouth Unconditioned Response—sucking reflex Conditioned Stimulus/Neutral Stimulus—baby sees breast or bottle before receiving nipple Conditioned Stimulus—anticipatory sucking movements begin when infant sees breast or bottle Little Albert and John B. Watson (1920)

Instrumental Operant Conditioning Most research focuses on positive reinforcement Infants form contingency relationships the infant makes a response the infant receives reinforcement Infants learn they can have an effect on a situation Mobile experiments (Rovee-Collier, 1997) Observational Learning Infant Imitation At birth? Clearly evident at 6 months of age Infants imitate other humans, not objects

Cognition Object Permanence A-Not-B Error Occurs earlier than what Piaget predicted Studied using violation-of-expectancy Infants as young as 3½–4½ months will look longer at impossible events than possible events A-Not-B Error Occurs earlier than what Piaget predicted and may be dependent on certain factors Less error with age Less likely to go back to A if A and B are distinct More likely to commit error as delay between A and B trials increases More likely to commit error as number of times object hidden at A increases Better at looking than searching

Possible versus impossible events In a classic series of tests of object permanence, Renée Baillargeon and her colleagues first habituated young infants to the sight of a screen rotating through 180 degrees. Then a box was placed in the path of the screen. In the possible event, the screen rotated up, occluding the box, and stopped when it reached the top of the box. In the impossible event, the screen rotated up, occluding the box, but then continued on through 180 degrees, appearing to pass through the space where the box was. Infants looked longer at the impossible event, showing they mentally represented the presence of the invisible box. (From Baillargeon, 1987)

Physical Knowledge Research about objects supporting each other At 3 months—Does contact exist? At 5 months—What type of contact? At 6½ months—What is the amount of contact? At 12½ months—What is the shape of the object?

Infants’ developing understanding of support relations (Adapted from Baillargeon, 1998)