Understanding the role of eye movements during reading using eye movement analysis with hidden Markov models (EMHMM)

Abstract

Does eye movement behavior during reading play an important role in reading performance? Here we focused on the English as a second language learners and investigated how eye movements, in addition to linguistic knowledge, and cognitive abilities are associated with reading performance. We used Eye Movement analysis with Hidden Markov Models (EMHMM) to quantify participants’ eye movement pattern and consistency. In Study 1, we focused on isolated word reading tasks including lexical decision, word naming, pseudoword naming, and word semantic judgment. We showed that higher similarity to an eye movement pattern that focused at the optimal viewing position and better local visual processing ability were associated with faster lexical decision response time (RT), in addition to working memory and lexical knowledge. Shorter pseudoword naming RT was associated with more consistent first eye fixation, in addition to working memory, selective attention and lexical knowledge. In contrast, performances in other reading tasks were not associated with eye movement pattern or global-local processing abilities. Thus, visual processing abilities are important factors relating with lexical decision and pseudoword naming performance. In Study 2, we focused on sentence/passage reading tasks including sentence semantic judgment and passage comprehension. We showed that eye movement consistency across trials and saccade length were associated with sentence semantic judgment RT, and only saccade length was associated with passage reading performance in RT. In contrast, eye movement pattern, i.e., where participants looked, was not associated with any reading performance. This result may be because compared with isolated word reading, sentence/passage reading involved more cognitive processes for combining lexical representations of words in sentences with different syntactic structures, and therefore eye movement consistency across sentences and saccade length, rather than eye fixation locations, were more associated with performance. In Study 3, we examined whether musicians have higher sensitivity to structural regularity during reading as reflected in sentence reading time and eye movements across languages. We hypothesized that while musicians may have higher sensitivity to structural regularity in English and Chinese reading as reflected in reading fluency, they may have higher sensitivity as reflected in eye movement planning in English due to similarities in perceptual demands on processing sequential symbol strings separated by spaces, but not in Chinese due to its logographic nature and lack of word boundaries. Musicians showed higher sensitivity to linguistic irregularities than non-musicians as reflected in longer reading time and more dispersed eye movement pattern when reading incorrect than legal English sentences. In Chinese, musicians’ higher sensitivity was reflected only in sentence reading time but not in eye movement pattern. Thus, musicians’ higher sensitivity to structural regularity was reflected in perceptual processes/eye movements only in reading languages with similar perceptual demands on processing sequential symbol strings separated by spaces. These results suggested that more consistent eye movements during reading were associated with higher reading efficiency at both isolated word and sentence processing. Also, eye movements during sentence reading could be associated with music expertise, and it depended on the similarities of the processes involved.