| dc.description.abstract | Previous findings have shown that statistical learning (SL) is distinct from other cognitive abilities, and is related to language acquisition and proficiency. However, the close relationship between SL and language processing is mainly supported by the findings from tests that require extraction of regularity embedded within temporal arrays, which are similar to alphabetic writing systems. Whether such relationship can be identified in tests whose stimuli are similar to non-alphabetic writing systems, such as Chinese, remains to be determined. Furthermore, a significant proportion of the research on SL had used verbal stimuli, which have been shown to be under the influence of people’s language experience. To investigate the relationship between SL and Chinese literacy optimally, there is a need to create and to validate a new SL test that employs non-verbal stimuli to resemble the characteristics of Chinese orthography.
In the present study, we developed novel componential visual SL (C-VSL) tests, and examined their characteristics in behavioral (Experiment 1 and 2) and neurophysiological (Experiment 3) experiments. Specifically, in the temporal and spatial C-VSL tests two nonverbal shapes were presented in sequential and simultaneous pairs, respectively. In the study phase, each shape always appeared in a specific position in the temporal or spatial pair, while the other shape in the same pair was not specific or unique. In the test phase, each shape encountered in the study phase, either in the same or different position as in the study phase, was paired with a novel shape that was not encountered before. Participants’ sensitivity to the stimulus positional regularity in the temporal and spatial C-VSL tests was measured by familiarity judgment and recognition in the test phase. In Experiment 1 and 2, participants’ basic cognitive abilities, including IQ and verbal/nonverbal working memory, and their performance in the conventional SL tests in both the visual and auditory modalities were measured to investigate their correlation with the C-VSL abilities. In addition, we recruited alphabetic and logographic readers for both Experiment 1 and 2, and in Experiment 2 further measured their sensitivity to Chinese orthography in a standard lexical decision task, as well as their proficiency to a non-native language, to explore the effects of literacy and C-VSL abilities on each other. In Experiment 3, the neural correlates of the sensitivity to the temporal and spatial componential regularity were identified using the ERP methodology.
The results showed that the newly developed temporal and spatial C-VSL tests are valid in measuring participants’ sensitivity to positional dependency. The behavioral accuracies in the temporal and spatial C-VSL tests correlated with each other but not with the performance in the conventional SL tests or with IQ. Consistent with the previous results from our laboratory, alphabetic readers’ performance in the tests of sequential VSL, temporal C-VSL, and spatial C-VSL correlated with their knowledge of novel Chinese orthography, supporting the relationship between SL and literacy acquisition. On the other hand, performance of none of the SL tests correlated with the language performance reliably in Taiwanese participants, possibly due to the low variability in their scores in the linguistic tests. As for the neurophysiological correlates of the performance in the temporal and spatial C-VSL tests, a significant N400 component and a sparse MMN component were identified, respectively. These results are generally in line with the previous ERP literature.
In summary, we have successfully developed SL tests that measure participants’ sensitivity to positional regularity presented in temporal and spatial pairs of nonverbal stimuli. The abilities measured in the C-VSL tests is distinct from the abilities measured in the sequential SL tests that are commonly employed in the previous literature. Despite the high correlation between the abilities measured in the temporal and spatial C-VSL tests, the ERP results suggest that these two abilities are subserved by distinct neural mechanisms. Based on the C-VSL tests developed in the present study, the relationship between SL and Chinese literacy can be explored further in future research.
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