Cognitive Development in Infancy

1. Cognitive Development in Infancy

4. New term definitions • Early Term: Between 37 weeks 0 days and 38 weeks 6 daysFull Term: Between 39 weeks 0 days and 40 weeks 6 daysLate Term: Between 41 weeks 0 days and 41 weeks 6 daysPostterm: Between 42 weeks 0 days and beyond • Dr. Jeffrey L. Ecker, chair of the American College of Obstetricians and Gynecologists’ (ACOG) Committee on Obstetric Practice. ACOG, and the Society for Maternal-Fetal Medicine (SMFM) wrote the joint opinion paper published in the journal Obstetrics & Gynecology. • Read more: New (And Hopefully Improved) Definition of Term Pregnancy | TIME.comhttp://healthland.time.com/2013/10/22/new-and-hopefully-improved-definition-of-term-pregnancy/#ixzz2lI5RyHJt

5. Questions • Describe different “developmental job descriptions” of early infancy • Describe different mechanisms of learning in infancy • Indicate two infant predictors of adolescent’s intelligence • Does rapidity of habituation predict future intelligence? Why do you think so? • What are the strengths and limitations of the habituation paradigm? • Video resources • Rovee-collier, infant brains, visual cliff, habituation

6. Developmental job descriptions • Body-Builder (O-9 weeks). • Inventory Control Officer (10-24 weeks) • Map Maker, Level I (25-40 weeks) • Map Maker, Level II (41-52 weeks) • Rovee-Collier, 1996, “Shifting the focus from what to why” Infant Behavior and Development

7. Body-Builder (O-9 weeks) • What I do and need • Part-time work days and nights acquiring energy and minimizing energy expenditure. Variable hours. • Persistence required; strong suck and cry desirable. • Net energy income will be invested in fueling growth. • Around-the-clock protection and personal shopper service available. • Practical implications • Great at sucking and looking to control environment • But kicking requires too much energy

8. Inventory Control Officer (10-24 weeks) • What I do and need • Full-time days/occasional nights maintaining and controlling inventory of people and objects, what goes with what, and what happens when and in what order. • Must be adept at soliciting caregiving and social interactions. Regular hours, benefits. • Practical implications • Can kick to show sophisticated memory for events and objects

9. Experimental example • An infant’s foot was attached to a mobile. • Initially, the infant would kick just by chance. • Each kick followed by the mobile’s movement. • This movement was interesting to the infant, and reinforced the kicking behavior, • increasing the likelihood that the infant would kick again. • Video Real life example: https://www.youtube.com/watch?v=lPJiB-oGMN0

10. Map Maker positions • Level I (25-40 weeks) • Full-time days, weekends; no nights. Regular hours. • Acquisition of preliminary cognitive map; some babbling, receptive language skills desired. • Beginning-level crawling a must. • Level II (41-52 weeks) • Full-time days, weekends, no nights. • Regular hours. Self-starter. Navigational and receptive language skills required. • Must know when who and what are where, and how to get there. • Rovee-Collier, 1996, Shifting the focus from what to why

11. Visual cliff and social information processing • A parent’s smiling face will convince an infant to cross over the visual cliff before they have begun to crawl—social referencing. Visual Cliff

12. The Epigenesis of Wariness of Heights • Human infants with no crawling experience show no wariness of heights, but wariness becomes strong over the life span. • The crucial component of locomotor experience in this emotional change is developments in visual proprioception—the optically based perception of self-movement. • Precrawling infants randomly assigned to drive a powered mobility device showed significantly greater visual proprioception, and significantly greater wariness of heights, than did controls.

13. Basic learning mechanisms • Classical Conditioning • infant responds to a stimulus • Operant Conditioning • Infant action changes the likelihood that an action will occur. • Habituation and Dishabituation • http://www.cogs.susx.ac.uk/users/alisonp/dev1/lecture2.html

14. Classical Conditioning • With repeated pairings of neutral stimulus and unconditioned stimulus, the infant begins to respond to the neutral stimulus. • The neutral stimulus is referred to as a conditioned stimulus, and the response as a conditioned response. • Classical conditioning helps infants understand which events “go together,” to anticipate what happens next. • Helps them learn to make sense of their environment. • Classical conditioning of reflexes

15. Classical conditioning at one month • Sleeping infants presented with 'social' (voice) or non-social stimulus (eg backward voice) followed by an airpuff to the eyelid. • Infants increased learning across trials, regardless of stimulus type. • Infants conditioned to the 'social' stimulus showed increased learning compared to infants conditioned the non-social stimuli.

16. Operant conditioning • A behavior followed by a stimulus that changes the likelihood of the behavior occurring again. • A stimulus that makes a behavior more likely to occur again is a reinforcer. Two kinds of reinforcers: • presentation of a desired stimulus • removal of an unpleasant stimulus. • A stimulus that makes a behavior less likely to occur again is called punishment. • Two kinds of punishment: • removal of a desired stimulus • presentation of an unpleasant stimulus.

17. Operant conditioning in research on infant perception • Using operant conditioning, researchers can “teach” infants to respond to a stimulus. • By varying the stimulus slightly, researchers can see whether infants perceive the variation. • To discover which stimuli infants are able to perceive, and which stimuli infants prefer. • Infants have a limited repertoire of responses--studies usually use sucking or head turn as the behavior which is reinforced.

18. Examples: operant conditioning • A pacifier with which infants controlled, by sucking or stopping sucking, whether they heard the mother’s voice or another woman’s voice. • Allowed the researchers to determine that infants were capable of perceiving the difference between the voices. • Testing infant hearing • Infants trained to turn their heads in response to a sound • Head turning is reinforced by the sight of toys which light up and become active when the infant turns. • The sound is then produced more and more quietly, to determine what sounds the infant is able to perceive.

19. Operant conditioning in development • When infants smile or vocalize, parents often respond by smiling or vocalizing in return. • The parent’s response may reinforce the infant, increasing the likelihood that the behavior will recur. • Parents can be operant conditioned by their infants as well. • When a parent is effective in soothing a crying infant, the infant stops crying. • This removal of an unpleasant stimulus (crying) reinforces the parent’s soothing technique, and the parent is more likely to use the same technique the next time the infant cries.

20. Operant conditioning in robotics? “A new approach to reinforcement learning for control problems which combines value-function approximation with linear architectures and approximate policy iteration.” Lagoudakis & Parr, 2003

21. More complex rewards… • http://www.sciencedirect.com/science?_ob=ArticleURL&_ “use the reduction of uncertainty (information gain) as a reward signal. The result is an interesting form of learning in which the learner rewards itself for conducting actions that help reduce its own sense of uncertainty” • udi=B6T08-511R9KT-1&_user=687815&_coverDate=11%2F30%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000038378&_version=1&_urlVersion=0&_userid=687815&md5=cd099de9f3a0e4a79f915ccd365e8750&searchtype=a

22. Stimulus

23. This pattern • Was presented to 93 premature infants for 60 sec. • Infants who gazed at the pattern for more time had lower intelligence at 18 years if age. • Infants who gazed at the pattern for less time had higher intelligence • Fixation duration in infancy and score on the intelligence test, r(91) = -.36, p < .0002. • Why?

24. Why does Infant Attention Predict Intelligence? • Three Theories • Speed or efficiency of information processing • Inhibition of responses to uninformative/familiar • Sigman et al., 1991 • Fixation taps processing • Sigman, Cohen, Beckwith, 1997

25. 18 Year IQ Depends on Infant Attention and Caregiver Behavior What conditions predict intelligence? Inexact rendition of Sigman, Cohen, & Beckwith (1997) N=25 N=24 N=22 N=20

26. Maternal vocalization • More maternal vocalizing at 1 month • Associated with vocalizations at 8 & 24 months and with socioeconomic status • Also predicts greater adolescent intelligence • R2 = .22 for gazing and maternal vocalizations • Infants who gaze briefly and who were vocalized to more show especially high intelligence. • Interaction effect

27. Infant habituation child intelligence • ‘Habituation and recognition memory in first year of life predict IQ between 1 and 8 years • Weighted (for N) mean correlation of .36 • Raw median correlation of .45. • Similar for habituation & recognition memory. • Predictions consistently higher than for standardized infant tests of general development for nonrisk but not for risk samples. • For nonrisk samples, predictions not consistently higher than predicting from parental education and socioeconomic status! • A Meta-Analysis of Infant Habituation and Recognition Memory Performance as Predictors of Later IQ Robert B. McCall, Michael S. Carriger Child Development, Vol. 64, No. 1 (Feb., 1993), pp. 57-79

28. Habituation as a measure of cognitive function? • A measure of learning and memory: • habituation implies that the infant has encoded some of its properties & retained them. • Habituation rate is linked to later achievement. • Individual differences in speed of habituation relates to later IQ scores (Fagan & Singer, 1983). • www.cogs.susx.ac.uk/users/alisonp/dev1/lecture2.html • Bored faster  Brighter??

29. Bored faster  Brighter?? • http://www.youtube.com/watch?v=dlilZh60qdA from 1:30

30. Habituation and dishabituation • Habituation - gradual reduction in the strength of a response as the result of repetitive stimulation. • When infants look at one stimulus for long period, they habituate, and look away more rapidly. • Dishabituation occurs when a new stimulus is presented, infants look at new stimulus longer • Enables infants to pay attention to new stimuli

31. Gene x SES & Mental Ability (MA) • SES-related disparities in MA • SES differences increase from 10mos to 2yrs • General contribution of genes & environment • Heritability higher at age 2 • SES interacts with genes & environment • SES moderates genetic contribution to MA change • Increasing heritability of MA in infancy most evident for high SES • Tucker-Drob, E. M., Rhemtulla, M., Harden, K. P., Turkheimer, E., & Fask, D. (2011). Emergence of a Gene × Socioeconomic Status Interaction on Infant Mental Ability Between 10 Months and 2 Years. Psychological Science, 22(1), 125-133. Fernandez

32. Effect of genes on mental ability increases over infant development in high SES case (Tucker-Drob, et al.. (2011) Fernandez

33. Fagan Test of Infant Intelligence • Assesses cognitive development in infancy. • Composed of habituation-dishabituation items. • “a “novelty score” -- amount of fixation during the test phase devoted to the novel picture divided by the total fixation time to both the novel and familiar picture.” • http://infantest.com/ftii.pdf • Used for research studies—index of the relative level of functioning in group being studied • Does not determine an individual child’s performance relative to that of the children in the norming sample – like in the Bayley

34. Difficulties in assessing cognitive development in infancy • Infants may become distracted, tired, or bored. • It’s hard to motivate infants to perform at their best. • Interpretation of measurable dependent variables (e.g., looking time) is key

35. Normed assessments of cognitive development in infancy • Research • Exposure differences, prematurity differences • Identification of infants at risk for developmental delay in order to provide early intervention services. • Scaled scores used at every age

36. Bayley Scales of Infant Development II (1993) • Permits observation of concepts noted by Piaget: • A not B search error • intentional, goal-directed behavior. • performance is compared with large group of infants on whom the test was normed. • Applied developmental research • 1 through 3 ½ years • Extensively normed • Basis for early referral • Test-retest reliability • http://www.youtube.com/watch?v=76SRamqYn0A&feature=relatedblue puzzle • http://www.youtube.com/watch?v=kpx4AgO-Oxw&feature=relmfuyellow pegs • http://www.youtube.com/watch?v=y1-ANMq1Cwo&feature=relmfudoll Mullen Scales are alternate assessment

37. One Year Mental Making speech sounds and words Fitting a piece in puzzle Basic motor tasks Motor Standing, walking, & throwing Two & three year Mental Uses multiple words in phrases Completing puzzle Counting & concepts Motor Runs, jumps, copies shapes What’s on the test? A series of difficulty-graded items Cognitive performance becomes more verbal. Children have to make verbal responses and understand more complex verbal instructions