Representational pattern similarity of electrical brain activity reveals rapid and specific prediction during language comprehension

Abstract

Predicting upcoming stimuli and events is a critical function of the brain, and understanding the mechanisms of prediction has thus become a central topic in neuroscientific research. Language provides a fertile testing ground for examining predictive mechanisms, as comprehenders use context to predict different features of upcoming words. Although there is a substantive body of research on prediction in language, many aspects of the mechanisms of prediction remain elusive, in part due to a lack of methodological tools to probe prediction formation in the moment. To elucidate what features are neurally pre-activated and when, we used representational similarity analysis (RSA) on data from a sentence reading task . We compared EEG activity patterns elicited by expected and unexpected sentence final words to patterns from the preceding words of the sentence, in both strongly and weakly constraining sentences. Pattern similarity with the final word was increased in an early time window (suggestive of visual feature activation) following the presentation of the pre-final word, and this increase was modulated by both expectancy and constraint (greatest for strongly constrained expected words). This was not seen at earlier words, suggesting that predictions are precisely timed.Additionally, pre-final word activitythe predicted representation -had negative similarity with later final word activity, but only for strongly expected words.Together, these findings shed light on the mechanisms of prediction in the brain:features of upcoming stimuli are rapidly pre-activated following related cues, but the predicted information may receive reduced subsequent processing upon confirmation.

Connecting and considering: Electrophysiology provides insights into comprehension

“…Effects of matching versus mismatching the gender or phonological features of the predicted word have been seen as soon as those features are encountered, at articles or adjectives that precede the anticipated noun, attesting that this information was, in fact, activated in advance. To even more directly measure predictive preactivation, Hubbard and Federmeier (2021b) used Representational Similarity Analysis, showing that EEG activity patterns for expected words, especially in strongly constraining sentences, can already be detected at the immediately preceding word. This signature of prediction was seen in an early time window, suggestive of visual feature activation (cf., Dikker & Pylkkänen, 2013).…”

Exploring age-related changes in inter-brain synchrony during verbal communication

“…These age-related changes in the use of predictive preactivation are particularly important in the context of communication dynamics and accommodation because one impact of preactivation is to fundamentally shift the time course with which information becomes and stays available. When younger adults are predicting, they preactivate information about likely upcoming words (DeLong et al, 2012;Van Berkum et al, 2005;Dikker et al, 2009;Dikker & Pylkkanen, 2011;Dikker & Pylkkänen, 2013), in a manner that is timed to anticipate the presentation of that word (Dikker & Pylkkänen, 2013;Hubbard & Federmeier, 2021). When the prediction is successful, the processing of that predictable word is then reduced at the time that it is actually encountered (Rommers & Federmeier, 2018a) -with downstream consequences for how well it will later be remembered (Hubbard et al, 2019).…”