Infants’ learning of non‐adjacent regularities from visual sequences

Abstract

Tracking adjacent (AD) and non‐adjacent (NAD) dependencies in a sequence of elements is critical for the development of many complex abilities, such as language acquisition and social interaction. While learning of AD in infancy is a domain‐general ability that is functioning across different domains, infants’ processing of NAD has been reported only for speech sequences. Here, we tested 9‐ to 12‐ and 13‐ to 15‐month‐olds’ ability to extract AxB grammars in visual sequences of unfamiliar elements. Infants were habituated to a series of 3‐visual arrays following an AxB grammar in which the first element (A) predicted the third element (B), while intervening X elements changed continuously. Following habituation, infants were tested with 3‐item arrays in which initial and final positions were switched (novel) or kept consistent with the habituation phase (familiar). Older infants successfully recognized the familiar AxB grammar at test, whereas the younger group showed some sensitivity to extract to NAD, albeit in a less robust form. This finding provides the first evidence that the ability to track NAD is a domain‐general ability that is present also in the visual domain and that the sensitivity to such dependencies is related to developmental changes, as demonstrated in the auditory domain.

Learning non-adjacent rules and non-adjacent dependencies from human actions in 9-month-old infants

“…These two experiments show that 9-month-old infants have the capacity to learn two different types of non-adjacent dependencies in temporally sequenced stimuli. The findings contrast with those from prior studies that used different types of visual stimuli [ 15 , 19 , 43 ], indicating that stimulus differences are likely to be substantially responsible for the differences in results.…”

“…This contrasts with some findings in the speech domain that suggest that learners require greater variability in the medial items in order to detect the NADs [ 21 , 22 ]; though it is consistent with more recent studies that have shown that at least adults can learn NADs with only three different intervening elements [ 30 , 31 ]. The results also contrast with the results for 9- to 12-month-old infants in Bettoni et al’s study [ 43 ], where subjects did not show evidence of discriminating consistent versus inconsistent test trials. As we mentioned earlier, the dependent items in that study were geometric shapes, and the intervening items were arrays of dots.…”

“…If so, we cannot say whether or not this was critical to infants’ success in learning the NADs. We speculate that even if it was necessary, it may not have been sufficient to support learning; after all, in Bettoni et al’s study [ 43 ] where the NADs themselves were perceptually similar, and differed from the intervening items, 9-month-olds nevertheless did not learn the NADs. That was arguably a much more direct kind of cue than priming in Experiment 2.…”

“…Given infants’ success in learning ABA patterns in sequences of human actions, and given adults’ success in learning NADs from similar stimuli [ 40 – 42 ], we asked whether infants could learn NADs from sequences of human actions. We reasoned that, just as human actions supported ABA learning in the visual domain, compared to other stimuli [ 15 ], so might human actions support NAD learning where other stimuli do not, at least with 9-month-old infants [ 22 , 23 , 43 ]. To test this claim, in Experiment 2 we used visual human action sequences to examine 9-month-olds’ capacity to learn non-adjacent dependencies of the form aXb , where a and b each refer to a different specific item and X refers to one item from a class of items.…”

“…We are aware of one other study that tested NAD learning in visual sequences in infants. A recent study by Bettoni, Hermann, Brady, and Johnson [ 43 ] tested NAD learning in sequences of geometric shapes and arrays of dots. They found evidence of NAD learning in 13- to 15-month-olds, but not 9- to 12-month-olds.…”