UBC Theses and Dissertations
How perception constrains statistical learning across development Black, Alexis K.
This dissertation seeks to understand the underlying mechanism(s) of statistical learning (SL), defined as the capacity to extract structure from a perceptual stream by relying on the statistical properties of that stream (e.g., Aslin, 2017). I approach this question in two ways: by examining (1) the output representations of statistical learning (i.e., the quality of representations that emerge from a SL experience), and (2) the effect of input representations on SL (i.e., whether and how an individual’s prior knowledge filters and shapes SL). I hypothesized that (i) learners’ prior knowledge would impact the accessibility of units to SL, and thereby modify the process of learning; (ii) that SL is composed of more than veridical tracking of transitional probabilities between sounds; and (iii) that the interaction of prior knowledge and the underlying mechanisms of SL would relate to differences in learning outcomes across development. To test these hypotheses, I created a novel testing paradigm of the word segmentation SL task, in which participants’ knowledge of trisyllabic nonce words that were embedded in a continuous familiarization stream is probed by manipulating the nature of syllables in particular ordinal positions. Adult subjects were then tested on streams of speech that incurred varying degrees of perceptual load, either via the nature of the phonetic elements, or via an external and unrelated task. Children were similarly exposed to and tested on a stream of familiar sounds; I predicted that their performance should parallel that of adults under conditions of greater perceptual load. The results of these experiments confirm that underlying perceptual representations impact learners’ capacity for SL, and that the output of auditory SL tasks reflects more than the underlying statistics embedded in a continuous stream. Performance does not rest on underlying phonetic representations alone; rather, differences in executive function skills additionally impact the SL process.
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