2 INFANCYSensation: the detection of sensory stimulationPerception: the interpretation of what is sensed
3 THE NEWBORN’S READINESS FOR LIFE Newborn Reflexes – involuntary, automatic response to a stimuliSurvival – adaptive value, satisfy needs;breathing, sucking, swallowingPrimitive – not as useful, disappear 1st yearBabinski, swimming, grasping
5 Table 5.1 Major Reflexes in Full-Term Neonates (continued)
6 THE NEWBORN’S READINESS FOR LIFE Infant States: six levels of arousalPass through predictable pattern of states70% of time asleepDevelopmental Change in Infant StatesOverall sleep decreases, duration of episodes increasesREM – declines; less need for stimulation while asleep (Autostimulation theory)SIDS – leading cause of infant mortality
8 THE NEWBORN’S READINESS FOR LIFE Functions and Course of CryingState communicating distressDevelopmental changes in cryingShrill and nonrhythmic may indicate brain damageTends to diminish after first 3 months – maturation of brain, increased responsiveness from parents
9 METHODS USED TO STUDY THE INFANT’S SENSORY/PERCEPTUAL EXPERIENCES The Preference MethodDiscriminate between stimuliThe Habituation MethodFamiliarity leads to a lack of responseDishabituation – response to new stimuli
10 METHODS USED TO STUDY THE INFANT’S SENSORY/PERCEPTUAL EXPERIENCES The Method of Evoked PotentialsPresent a stimulus and record brain wavesDiscrimination of stimuli produces different brain wave patternsThe High-Amplitude Sucking MethodRate of sucking on a pacifier controls the presentation of a stimuli, shows preference and discrimination
11 Figure 5.3 An EEG cap is used to place electrodes around the baby’s head to record electrode activity at appropriate places on the baby’s brain.
12 Figure 5.4 The high-amplitude sucking apparatus.
13 INFANT SENSORY CAPABILITIES HearingDiscriminate sounds based on loudness, duration, direction, and frequencyPrefer mother’s voice to other womenSensitive to phonemes, even better than adults (if sounds are not part of the adult’s spoken language)Hearing loss can adversely affect development (often due to ear infections)
14 INFANT SENSORY CAPABILITIES Taste and SmellPrefer sweet over sour, bitter, or saltyAvoid unpleasant odorsRecognize mother by smell (if breast-fed)Touch, Temperature, and PainTouch enhances development, allows exploration of environmentSensitive to temperatureSensitive to pain – even at 1 day
15 INFANT SENSORY CAPABILITIES VisionLeast mature senseDetect changes in brightnessCan see patternsSee colors, although discrimination is good by 2-3 monthsPoor acuity, see as well as adults by 12 months
17 VISUAL PERCEPTION IN INFANCY Perception of Patterns and FormsEarly Pattern Perception (0 to 2 Months)Prefer high contrast patternsPrefer moderately complex patternsPrefer patterns that move
18 Figure 5. 5 Fantz’s test of young infants’ pattern preferences Figure 5.5 Fantz’s test of young infants’ pattern preferences. Infants preferred to look at complex stimuli rather than at a simpler black-and-white oval. However, the infants did not prefer the facelike figure to the scrambled face. ADAPTED FROM FANTZ, 1961.
19 Figure 5. 6 What patterns look like to the young eye Figure 5.6 What patterns look like to the young eye. By the time these two checkerboards are processed by eyes with poor vision, only the checkerboard on the left may have any pattern left to it. Poor vision in early infancy helps to explain a preference for moderately complex rather than highly complex stimuli. ADAPTED FROM BANKS & SALAPTEK, 1983.
20 VISUAL PERCEPTION IN INFANCY Later Form Perception (2 months – 1 year)More sensitive to movementBegin to perceive objects as whole formsUse subjective contoursResults from interaction between vision, biological maturation, and learning
21 Figure 5. 7 Perceiving objects as wholes Figure 5.7 Perceiving objects as wholes. An infant is habituated to a rod partially hidden by the block in front of it. The rod is either stationary (A) or moving (B). When tested afterward, does the infant treat the whole rod (C) as “familiar”? We certainly would, for we could readily interpret cues that tell us that there is one long rod behind the block and would therefore regard the whole rod as familiar. But if the infant shows more interest in the whole rod (C) than in the two rod segments (D), he or she has apparently not been able to use available cues to perceive a whole rod. ADAPTED FROM KELLMAN & SPELKE, 1983.
22 Figure 5.8 By 3 months of age, infants are perceiving subjective contours such as the “square” shown here. ADAPTED FROM BERTENTHAL, CAMPOS, & HAITH, 1980.
23 VISUAL PERCEPTION IN INFANCY Perception of Three-Dimensional SpaceSize ConstancyPresent at birth, not fully developed until 10 – 11 YEARS oldMovement cues important (1-3 months)Binocular cues important (3-5 months)Pictorial Cues (monocular)develop by age 6-7 months
24 Figure 5.10 If infants are sensitive to the pictorial cue of interposition, they should reliably reach for the “closest” area of a visual display (left side in this example). Seven-month-olds show this reaching preference, whereas 5-month-olds do not. FROM GRANRUD & YONAS, 1984.
25 VISUAL PERCEPTION IN INFANCY Development of Depth PerceptionUse of visual cliffMost infants at 6½ months (crawling) perceived depth2 month-olds showed decrease in heart rate – a sign of interest, but not fearExperience through motor development is important
26 Figure 5.11 An infant at the edge of the visual cliff.
27 INTERMODAL PERCEPTION Are the Senses Integrated at Birth?Yes: reaching for objects that are seenYes: looking in the direction of soundsYes: expecting to see source of sound, or to feel objects that were reached for
28 INTERMODAL PERCEPTION Development of Intermodal perception1-month-olds show weak oral-to-visual perception4 months – intermodal matching between vision and hearing4-6 months – match tactile and visual sensations
29 Figure 5.12 Mean times for infants to cross the visual cliff as a function of condition.
30 INTERMODAL PERCEPTION Explaining Intermodal PerceptionIntersensory redundancy hypothesisAmodal detection of a stimulus aids in development and differentiation of individual sensesAt birth – perception is amodalExperiencing multimodal stimuli leads to intermodal perception
31 CULTURAL INFLUENCES ON INFANT PERCEPTION Language – become sensitive to sounds important to specific languageEnglish vs. Chinese and “r” and “l”Music – familiar with own culture’s musicWestern major/minor vs. Javanese scaleGrowth of perceptual skills includes adding new skills and losing unnecessary onesCulture determines which sensory inputs are distinctive and how to interpret those inputs
32 BASIC LEARNING PROCESSES IN INFANCY Change in behavior thatProduces a new way to think about, perceive, or react to the environmentIs the result of experienceIs relatively permanent
33 BASIC LEARNING PROCESSES IN INFANCY Habituation – process by which we stop responding to a repeated stimulusDishabituation – attending to a new stimulusDevelopmental TrendsPossible before birth4 months – may take long exposure5-12 months – need a few seconds10-14 months – habituate to objects and relationships between objects
34 Figure 5.13 Support habituation and test events: Containment test events
35 Figure 5.13 Support habituation and test events: Containment test events (continued)
36 BASIC LEARNING PROCESSES IN INFANCY Individual Differences in HabituationSome habituate slowly and forget rapidlyOthers habituate rapidly and forget slowlyRapid habituation between 6-8 monthsBetter language skills in 2nd yearHigher IQ later in childhood
37 BASIC LEARNING PROCESSES IN INFANCY Classical ConditioningUnconditioned stimulus (UCS) elicits an unconditioned response (UCR)Neutral conditioned stimulus (CS) paired with (UCS)Eventually CS elicits a conditioned response (CR)Possible for newborns, but must have survival value
38 BASIC LEARNING PROCESSES IN INFANCY Operant ConditioningLearner emits a response (operates on environment)Associates this action with the consequences it producesRepeat favorable, limit unfavorableNewborns learn very slowly, rate increases with ageAt 2 months, memory is context-dependent
39 Figure 5.14 Basic principles of operant conditioning.
40 Figure 5.15 When ribbons are attached to their ankles, 2- to 3-month-old infants soon learn to make a mobile move by kicking their legs. But do they remember how to make the mobile move when tested days or weeks after the original learning? These are the questions that Rovee-Collier has explored in her fascinating research on infant memory.
41 BASIC LEARNING PROCESSES IN INFANCY Observational Learning –Attend to a model and form a symbolic representation of model’s behaviorNewborn imitation – possible at 7 days old, if part of behavioral repertoireImitation of novel responses – reliable between 8-12 months oldImmediate imitation at first, deferred imitation later
42 Figure 5.16 Sample photographs from videotaped recordings of 2- and 3-week old infants imitating tongue protrusion, mouth opening, and lip protrusion.