Biomedical subjects

Morten H Christiansen

Publications and source records attributed to Morten H Christiansen.

6 recordsLinked to original sources

PubMed2006

Phonological typicality influences on-line sentence comprehension.

Since Saussure, the relationship between the sound and the meaning of words has been regarded as largely arbitrary. Here, however, we show that a probabilistic relationship exists between the sound of a word and its lexical category. Corpus analyses of nouns and verbs indicate that the phonological properties of the individual words in these two lexical categories form relatively separate and coherent clusters, with some nouns sounding more typical of the noun category than others and likewise for verbs. Additional analyses reveal that the phonological properties of nouns and verbs affect lexical access, and we also demonstrate the influence of such properties during the on-line processing of both simple unambiguous and syntactically ambiguous sentences. Thus, although the sound of a word may not provide cues to its specific meaning, phonological typicality, the degree to which the sound properties of an individual word are typical of other words in its lexical category, affects both word- and sentence-level language processing. The findings are consistent with a perspective on language comprehension in which sensitivity to multiple syntactic constraints in adulthood emerges as a product of language-development processes that are driven by the integration of multiple cues to linguistic structure, including phonological typicality.

Cognition↗

PubMed2006

Statistical learning within and between modalities: pitting abstract against stimulus-specific representations.

When learners encode sequential patterns and generalize their knowledge to novel instances, are they relying on abstract or stimulus-specific representations? Research on artificial grammar learning (AGL) has shown transfer of learning from one stimulus set to another, and such findings have encouraged the view that statistical learning is mediated by abstract representations that are independent of the sense modality or perceptual features of the stimuli. Using a novel modification of the standard AGL paradigm, we obtained data to the contrary. These experiments pitted abstract processing against stimulus-specific learning. The findings show that statistical learning results in knowledge that is stimulus-specific rather than abstract. They show furthermore that learning can proceed in parallel for multiple input streams along separate perceptual dimensions or sense modalities. We conclude that learning sequential structure and generalizing to novel stimuli inherently involve learning mechanisms that are closely tied to the perceptual characteristics of the input.

Association Learning↗

PubMed2005

Stress changes the representational landscape: evidence from word segmentation.

Over the past couple of decades, research has established that infants are sensitive to the predominant stress pattern of their native language. However, the degree to which the stress pattern shapes infants' language development has yet to be fully determined. Whether stress is merely a cue to help organize the patterns of speech or whether it is an important part of the representation of speech sound sequences has still to be explored. Building on research in the areas of infant speech perception and segmentation, we asked how several months of exposure to the target language shapes infants' speech processing biases with respect to lexical stress. We hypothesize that infants represent stressed and unstressed syllables differently, and employed analyses of child-directed speech to show how this change to the representational landscape results in better distribution-based word segmentation as well as an advantage for stress-initial syllable sequences. A series of experiments then tested 9- and 7-month-old infants on their ability to use lexical stress without any other cues present to parse sequences from an artificial language. We found that infants adopted a stress-initial syllable strategy and that they appear to encode stress information as part of their proto-lexical representations. Together, the results of these studies suggest that stress information in the ambient language not only shapes how statistics are calculated over the speech input, but that it is also encoded in the representations of parsed speech sequences.

Female↗

PubMed2005

Modality-constrained statistical learning of tactile, visual, and auditory sequences.

The authors investigated the extent to which touch, vision, and audition mediate the processing of statistical regularities within sequential input. Few researchers have conducted rigorous comparisons across sensory modalities; in particular, the sense of touch has been virtually ignored. The current data reveal not only commonalities but also modality constraints affecting statistical learning across the senses. To be specific, the authors found that the auditory modality displayed a quantitative learning advantage compared with vision and touch. In addition, they discovered qualitative learning biases among the senses: Primarily, audition afforded better learning for the final part of input sequences. These findings are discussed in terms of whether statistical learning is likely to consist of a single, unitary mechanism or multiple, modality-constrained ones.

Auditory Perception↗

PubMed2004

The differential role of phonological and distributional cues in grammatical categorisation.

Recognising the grammatical categories of words is a necessary skill for the acquisition of syntax and for on-line sentence processing. The syntactic and semantic context of the word contribute as cues for grammatical category assignment, but phonological cues, too, have been implicated as important sources of information. The value of phonological and distributional cues has not, with very few exceptions, been empirically assessed. This paper presents a series of analyses of phonological cues and distributional cues and their potential for distinguishing grammatical categories of words in corpus analyses. The corpus analyses indicated that phonological cues were more reliable for less frequent words, whereas distributional information was most valuable for high frequency words. We tested this prediction in an artificial language learning experiment, where the distributional and phonological cues of categories of nonsense words were varied. The results corroborated the corpus analyses. For high-frequency nonwords, distributional information was more useful, whereas for low-frequency words there was more reliance on phonological cues. The results indicate that phonological and distributional cues contribute differentially towards grammatical categorisation.

Cues↗

PubMed2002

Reassessing working memory: comment on Just and Carpenter (1992) and Waters and Caplan (1996).

M. A. Just and P. A. Carpenter's (1992) capacity theory of comprehension posits a linguistic working memory functionally separated from the representation of linguistic knowledge. G. S. Waters and D. Caplan's (1996) critique of this approach retained the notion of a separate working memory. In this article, the authors present an alternative account motivated by a connectionist approach to language comprehension. In their view, processing capacity emerges from network architecture and experience and is not a primitive that can vary independently. Individual differences in comprehension do not stem from variations in a separate working memory capacity; instead they emerge from an interaction of biological factors and language experience. This alternative is argued to provide a superior account of comprehension results previously attributed to a separate working memory capacity.

Linguistics↗