Roles of function, reminding, and variability in categorization by 3-month-old infants.

Abstract

The roles of function, reminding, and exemplar variability in categorization of a physically dissimilar object were studied with 3-month-old infants trained to move a crib mobile by kicking. Performance on a transfer test with a motionless novel object provided evidence of categorization. In Experiments 1 and 2, infants, like adults, initially categorized novel objects on the basis of physical appearance, but only if trained with multiple exemplars, after delays of 1 and 7 days. In Experiment 3, prior knowledge of an object's functional properties overrode physical dissimilarity as the basis for categorization and enabled reminding of the classification response 2 weeks later. In Experiment 4, postevent contingency information overrode physical and functional properties as the basis for categorization. These findings indicate that expectations and goals influence infants' category decisions and raise the possibility that infants of 3 months respond by analogy.

Infants' eyewitness testimony: Effects of postevent information on a prior memory representation

“…The same finding had been obtained by Greco et al (1990) when, following variable training, they had exposed infants to a stationary object that bore no physical resemblance to the training mobiles. Greco et al found that the highly physically dissimilar object was integrated with the prior training memory, however, if they exposed infants to information about the object's function (movement), which it shared with the prior training exemplars.…”

“…Although Greco et al (1990) had found that the attributes of a novel object were not integrated with the prior training memory unless it was exposed in motion-a function it shared with the category-training exemplars-we thought that information about shared function might not be necessary because the novel mobile to which infants would be passively exposed more closely resembled the training mobile than that used in the earlier study.…”

“…In addition, Greco et al (1990) had trained infants with a different mobile in each session (variable training) prior to introducing information about the novel object; however, in the present studies, we wanted to train infants with the same object in every session (constant training). Before proceeding with the postevent-information procedure, therefore, we thought it also important to compare the effects of variable and constant training on infants' 24-h test performance to novel and familiar mobiles.…”

“…During testing, infants transferred responding to a mobile displaying the training character in a novel color (e.g., a purple A) but did not respond to a mobile displaying identically colored characters from the other category (e.g., a purple 2). When infants were passively exposed to a highly physically dissimilar novel object that was functioning in the same manner as the category exemplars immediately after training was over, however, they subsequently transferred responding to that novel object as well as to other novel objects that they had not previously seen; if they were exposed to the same novel object functioning differently, they treated the test object as unique and failed to perform the learned response (Greco et al, 1990). Because infants were only passively exposed to the shared functional information, and because this information was physically absent during testing 24 h later, transfer to the highly physically dissimilar object could not have been achieved unless the object's attributes had somehow been integrated with the infants' memory of category training at the time it was exposed.…”

Bidirectional priming in infants

“…Of particular interest for the present study is the consistent finding that infants' forgotten memory of one event is reactivated when their forgotten memory of a second, associated event is primed (Greco, Hayne, & Rovee-Collier, 1990; Rovee-Collier, Sheffield & Hudson, 1994;Timmons, 1994). Timmons, for example, trained 6-month-old infants to move a mobile by foot kicking and then to turn on a music box by arm waving, or vice versa (mobile-arm wave, music box-footkick).…”