Prosodic cues enhance infants' sensitivity to nonadjacent regularities.

In language, grammatical dependencies often hold between items that are not immediately adjacent to each other. Acquiring these nonadjacent dependencies is crucial for learning grammar. However, there are potentially infinitely many dependencies in the language input. How does the infant brain solve this computational learning problem? Here, we demonstrate that while rudimentary sensitivity to nonadjacent regularities may be present relatively early, robust and reliable learning can only be achieved when convergent statistical and perceptual, specifically prosodic cues, are both present, helping the infant brain detect the building blocks that form a nonadjacent dependency. This study contributes to our understanding of the neural foundations of rule learning that pave the way for language acquisition.

Developing knowledge of nonadjacent dependencies.

Characterizing the nature of linguistic representations and how they emerge during early development is a central goal in the cognitive science of language. One area in which this development plays out is in the acquisition of dependencies-relationships between co-occurring elements in a word, phrase, or sentence. These dependencies often involve multiple levels of representation and abstraction, built up as infants gain experience with their native language. The authors used the Headturn Preference Procedure to systematically investigate the early acquisition of 1 such dependency, the agreement between a subject and verb in French, at 6 different ages between 14 and 24 months. The results reveal a complex developmental trajectory that provides the first evidence that infants might indeed progress through distinct stages in the acquisition of this nonadjacent dependency. The authors discuss how changes in general cognition and representational knowledge (from reflecting surface statistics to higher-level morphological features) might account for their findings. These findings highlight the importance of studying language acquisition at close time intervals over a substantial age range. (PsycINFO Database Record

The perception of concurrent sound objects through the use of harmonic enhancement: a study of auditory attention.

When the frequency of one harmonic, in a sound composed of many harmonics, is briefly mistuned and then returned to the 'in-tune' frequency and phase, observers report hearing this harmonic as a separate tone long after the brief period of mistuning - a phenomenon called harmonic enhancement. Here, we examined the consequence of harmonic enhancement on listeners' ability to detect a brief amplitude notch embedded in one of the harmonics after the period of mistuning. When present, the notch was either on the enhanced harmonic or on a different harmonic. Detection was better on the enhanced harmonic than on a non-enhanced harmonic. This finding suggests that attention was drawn to the enhanced harmonic (which constituted a new sound object) thereby easing the processing of sound features (i.e., a notch) within that object. This is the first evidence of a functional consequence of the after-effect of transient mistuning on auditory perception. Moreover, the findings provide support for an attention-based explanation of the enhancement phenomenon.

Abstract rule learning in 11- and 14-month-old infants.

This study tests the hypothesis that distributional information can guide infants in the generalization of word order movement rules at the initial stage of language acquisition. Participants were 11- and 14-month-old infants. Stimuli were sentences in Russian, a language that was unknown to our infants. During training the word order of each sentence was transformed following a consistent pattern (e.g., ABC-BAC). During the test phase infants heard novel sentences that respected the trained rule and ones that violated the trained rule (i.e., a different transformation such as ABC-ACB). Stimuli words had highly variable phonological and morphological shapes. The cue available was the positional information of words and their non-adjacent relations across sentences. We found that 14-month-olds, but not 11-month-olds, showed evidence of abstract rule generalization to novel instances. The implications of this finding to early syntactic acquisition are discussed.