A total of eighty 9-month-old infants were presented with a problem consisting of several different conditions which separated response, position on a table, and absolute spatial position as factors leading to errors in search for hidden objects. (MS)

Proposes a theoretical sequence of cognitive developments as influencing representational play and language in the second year of life. Structural and temporal links between play and language indicate influence of developing mental representation, but variation in timing of developments points to influence of variables. (ET)

Two experiments used object-manipulation tasks to examine whether one- to two-year-olds form superordinate-like categories by attending to object parts. Findings indicated that 14- and 18-month-olds behaved systematically toward categories with different, but not matching, parts. Without part differences, none formed superordinate categories.…

This study examined how novel words foster the formation of object categories for 12- to 13-month olds. Results indicated that by 12 to 13 months, infants have begun to distinguish between novel words presented as count nouns versus adjectives in fluent, infant-directed speech, and that infants' expectations for novel words accord with this…

Two studies examined whether 1-year olds' name learning during joint attention was guided by expectation that names will be in the form of spoken words. Results showed that 13-month olds, but not 20-month olds, learned a new sound/object correspondence, as evidenced by their choosing targets reliably in responses to hearing the word or sound on…

Two experiments examined 6-month olds' ability to categorize natural infant-directed utterances. Infants heard seven different tokens from one class of utterance (comforting, approving). Findings indicated that infants who later heard a test stimulus from the unfamiliar class showed response recovery, whereas those who heard a novel stimulus from…

Evaluated infants' ability to form new object categories based on either visual or naming information at 16 and 20 months using an object manipulation task. Found that infants at both ages showed evidence of using visual information to categorize the objects. Only 20-month-olds used naming information. Found a correlation between vocabulary size…

Examined the effect of functional values of stimuli on orienting response elicitation. Subjects were 50 4-month-old infants and were randomly assigned to 1 of 3 experimental conditions. Results suggested the importance of taking into account the functional value of stimuli when analyzing infant attention. (MOK)

Examined whether 6-month-olds expect people to behave differently toward persons and inanimate objects. Found that infants habituated to an actor talking to something hidden behind an occluder looked longer at an object, whereas infants habituated to an actor reaching and swiping looked longer at a person. No difference in looking at stimuli was…

Examined representation of pictorial exemplars of humans by 3- and 4-month olds. Results demonstrated an asymmetry regarding the exclusivity of categorical representations formed for humans and non-human animals. Categorical representations for humans included exemplar information, whereas categorical representation for non-human animals was based…

Two experiments examined whether associating an imitation task with an operant task affected 6-month-olds' memory for either task. Results indicated that infants successfully imitated a puppet's action for up to 2 weeks only if the associated operant task (pressing a lever to activate a miniature train) was retrieved first. Follow-up study…

Infants' abilities to identify objects based on their perceptual features develop gradually during the first year and possibly beyond. Earlier we reported [Kaldy, Z., & Leslie, A. M. (2003). Identification of objects in 9-month-old infants: Integrating "what" and "where" information. Developmental Science, 6, 360-373] that infants at 9 months of…

Recent infant studies indicate that goal attribution (understanding of goal-directed action) is present very early in infancy. We examined whether 6.5-month-olds attribute goals to agents and whether infants change the interpretation of goal-directed action according to the kind of agent. We conducted three experiments using the visual habituation…

Human infants imitate others' actions "rationally": they copy a demonstrator's action when that action is freely chosen, but less when it is forced by some constraint (Gergely, Bekkering & Kiraly, 2002). We investigated whether enculturated chimpanzees (Pan troglodytes) also imitate rationally. Using Gergely and colleagues' (2002) basic procedure,…