An exploratory data analysis of word form prediction during word-by-word reading

In 2005, we reported evidence indicating that upcoming phonological word forms-e.g., kite vs. airplane-were predicted during reading. We recorded brainwaves (electroencephalograms [EEGs]) as people read word-by-word and then correlated the predictability in context of indefinite articles that preceded nouns ( vs. ) with the average event-related brain potentials (ERPs) they elicited [K. A. DeLong, T. P. Urbach, M. Kutas, Nat. Neurosci. 8, 1117-1121 (2005)]. Amid a broader controversy about the role of word-form prediction in comprehension, those findings were recently challenged by a failed putative direct replication attempt [M. S. Nieuwland et al., eLife 7, e33468 (2018); nine labs, one experiment, and 2.6e4 observations]. To better understand the empirical justification for positing an association between prenominal article predictability and scalp potentials, we conducted a wide-ranging exploratory data analysis (EDA), pooling our original data with extant data from two followup studies (one lab, three experiments, and 1.2e4 observations). We modeled the time course of article predictability in the single-trial data by fitting linear mixed-effects regression (LMER) models at each time point and scalp location spanning a 3-s interval before, during, and after the article. Model comparisons based on Akaike information criteria (AIC) and slope-regression ERPs [rERPs; N. J. Smith, M. Kutas, Psychophysiology 52, 157-168 (2015)] provide substantial empirical support for a small positive association between article predictability and scalp potentials approximately 300 to 500 ms after article onset, predominantly over bilateral posterior scalp. We think this effect may reasonably be attributed to prediction of upcoming word forms.