Poster group
Details of individual items:
poster
Imitation of facial gestures in early infancy has received specialattention from a variety of orientations, such as perception, cross-modalcoordination, representation, learning, memory, communication andself ( Meltzoff & Moore,1995). To investigate genetic mechanismsunderlying early tongue protruding imitation, 32 preterm infants between24 and 36 weeks gestational age at birth were tested at postconceptional(corrected gestational ) age between 32 and 45 weeks, and 18 full-termneonates between 37 and 41 weeks gestational age were tested within firstsix days after birth. Subjects were presented with moving tongueprotrusions in two realistic (a schematic face and an eyes pattern) and twononrealistic (a scrambled face and a contour pattern) face patterns afterpresentations with tongue protruded stationary four face patterns. Resultsshowed that four face patterns received significantly more attention andreproduction of tongue protrusions when moving than when stationary. Inquantitative analyses, most preterms looked at and imitated more tongueprotrusions in the schematic face, the eyes pattern and the scrambled facethan those in the contour pattern. Interestingly in the qualitativeanalyses, among preterm infants of same gestational age at birth, severalpreterms tested at earlier postconceptional ages produced preferentialimitation for realistic faces over nonrealistic ones, while preterms testedat later postconceptional ages did not. The on set of preferential tongueprotruding imitation for realistic faces emerged at as early as 33 weekspostconceptional age. This precocious face preference suggestedidentification of our species, developing of the ecological andinterpersonal selves (Neisser,1995), proto-phase in 'theory ofmind'(Butterworth,1994), still long extrauterine stimulus generalizationperiod including imitating tongue protrusions of the scrambled face wereneeded for subsequent re-emergence of selective face preference at first 3months of life (Ikegami,1984).
poster
Currently, there is renewed interest in Vygotsky's socialinteractionist view of cognitive development. In the field of imitation,Uzgiris (1981) pointed out that much of research has focused on thecognitive function of imitation, while less has focused on the socialinteraction per se. While use of deferred imitation as a tool toinvestigate memory processing during infancy has flourished, this paradigmhas only rarely been used to investigate the social conditions under whichimitation might develop. Hanna and Meltzoff (1993) found that 14-month-oldinfants imitated the actions of a peer when they were tested both 5 minand 2 days later in a different context. Furthermore, observationalstudies have shown that 18-month-olds do imitate their older siblings(e.g., Lamb, 1978) and a recent diary study of 12- to 18-month-olds withsiblings, has shown that approximately half of the actions they imitatedhad been modeled by other children (Barr & Hayne, in press). Takentogether, these findings reveal that siblings and peers are importantsocial models. In the present study we examined whether 9- and 12-month-oldinfants could learn an operant task by watching their sibling perform it.The train task requires infants to press a lever to make a miniature trainmove around a circular track (Hartshorn & Rovee-Collier, 1997). Duringbaseline and test phases, lever pressing did move the train. During the1-min baseline phase, 9- and 12-month-olds unlearned rate of leverpressing was recorded. Next followed a 2-min demonstration phase, duringwhich an older sibling modeled lever- pressing to make the train move.During the 2-min test phase, which followed either immediately or 24 hoursafter the demonstration, infants lever presses were again recorded whilethe lever was deactivated. At both 9 and 12 months, infants respondedsignificantly above baseline whether they were tested immediately or aftera 24-hour delay, indicating significant evidence of imitation. Behavioralarousal control groups at each age saw no demonstration but were shown thetrain moving noncontingently for 2 min. Even when tested immediatelyafterward, neither of these groups responded above baseline. The present findings extend prior findings of peer imitation toyounger infants and reveal that imitation is a powerful mechanism by whichinfants can rapidly acquire new behaviors. More importantly, thesefindings reveal that infants can even perform a learning task vicariouslyby merely watching a sibling produce a rewarding outcome. This findingincreases the significance of the role that imitation plays for the veryyoung.References Barr, R. & Hayne, H. (in press). Age-related changes inimitation: Implications for memory development. In C. Rovee-Collier, L.P. Lipsitt, & H. Hayne (Eds.),Progress in infancy research (Vol. 1).Hillsdale, NJ: Erlbaum. Hanna, E., & Meltzoff, A. N. (1993). Peer imitation inlaboratory, home and day care contexts: Implications for social learningand memory. Developmental Psychology, 29, 1-12. Hartshorn, K. & Rovee-Collier, C. (1997). Infant learning andlong-term memory at 6 months: A confirming analysis. DevelopmentalPsychobiology, 30, 71-85. Lamb, M. E. (1978). The development of sibling relationships ininfancy: A short-term longitudinal study. Child Development, 49,1189-1196. Uzgiris, I. C. (1981). Two functions of imitation during infancy.International Journal of Behavioral Development, 4, 1-12.
poster
Several conflicting explanations for early imitation have beenoffered. However, few studies have specifically investigated theseexplanations. Meltzoff and his colleagues suggest that imitation isemployed as a method of identifying and communicating with otherindividuals. They suggest that infants repeat the actions of othersin order to ask, 'Are you the one who does this?' (Meltzoff & Moore,1992, 1994, 1995). Others also point to the social-communicativefunction of imitation, showing the role that this social-learningstrategy plays in language acquisition, and peer relationships(Eckerman, 1993; Grusec & Abramowitch, 1982). Previous research byMeltzoff (1990) has suggested that between 9- and 14-months of ageinfants begin to smile, look and perform 'testing behaviors' inresponse to people who are imitating them. Meltzoff suggests that by14 months of age, infants become sensitive to the fact that they arebeing imitated and that they are aware of the communicativesignificance of an imitative interaction. The present investigationexplores if and when infants employ imitated actions to re-initiatesocial interaction. The current study serves two purposes: 1) toreplicate the findings of Meltzoff (1990) and 2) to investigatewhether imitation is used by the infant communicatively. In thecurrent procedure, infants face two experimenters, only one of whomimitates the infant. Following this interaction, the experimenterscease their active exchange with the infant. The behaviors that theinfants' employ to re-initiate further interaction are examined. Results are presented suggesting that by 14-months of age infantsrecognize that they are being imitated. Furthermore, when theexchange is disrupted, these same infants tend to re-initiate socialinteraction by employing the previously imitated actions of theexperimenter. In contrast, infants who do not recognize that they arebeing imitated tend not to employ the imitated actions in an attemptto re-initiate a discontinued social interaction. Thus, this researchnot only points to the sensitivity of 14-month-old infants to beingimitated but also establishes that infants do tend to employ imitatedacts to repair disrupted social interactions.
poster
Twenty-one infants, 11 young (age range, 8 to 13 months; M age11.3months) and 9 old (age range 14 to 18 months; M age16.4 months) werepresented with four imitation conditions, counterbalanced across infantparticipants. The conditions were: (1) a fully visible person performingnovel actions on objects, (2) a personUs disembodied hands performingnovel actions on objects, (3) a personUs disembodied mittened handsperforming actions on objects and (4) a pair of mechanical robot pincersperforming actions on objects. In each condition, two different imitationtrials were presented in which novel object-directed target actions weremodelled (eg. a dumbbell was pulled apart, a chain was hung on a peg, abox was shaken to make a rattling sound). For each trial, a 30-secondbaseline period established that the target action was not spontaneouslyperformed. Infants were scored for fully complete imitative responses (2points) as well as attempts at imitation (1 point) in trials where therewas no performance of the target action in the baseline. A 4 x 2(condition x age) ANOVA revealed a significant main effect for age,F(1,129)6.025, p.015, indicating that the older infants produced moreimitative responses than the younger infants. The ANOVA also revealed amarginal main effect for condition, F(3, 129)2.301, p.08, suggestingthat infants overall imitated some of the models more than others, andFisherUs post hoc tests showed that infants imitated the handssignificantly more than they imitated the robot pincers (p.018). Plannedpairwise comparisons revealed that older infants imitated the hands andthe person significantly more than the robot pincers (both tUs (25) > 2.1,pUs < .05), while the younger infants showed no differences in imitationacross conditions. These results suggest that older, but not youngerinfants, address their imitative responses specifically to other humans.