When function words carry content

Studies on eye movements during reading have primarily focussed on the processing of content words (CWs), such as verbs and nouns. Those few studies that have analysed eye movements on function words (FWs), such as articles and prepositions, have reported that FWs are typically skipped more often and, when fixated, receive fewer and shorter fixations than CWs. However, those studies were often conducted in languages where FWs contain comparatively little information (e.g., the in English). In Brazilian Portuguese (BP), FWs can carry gender and number marking. In the present study, we analysed data from the RASTROS corpus of natural reading in BP and examined the effects of word length, predictability, frequency and word class on eye movements. Very limited differences between FWs and CWs were observed mostly restricted to the skipping rates of short words, such that FWs were skipped more often than CWs. For fixation times, differences were either nonexistent or restricted to atypical FWs, such as low frequency FWs, warranting further research. As such, our results are more compatible with studies showing limited or no differences in processing speed between FWs and CWs when influences of word length, frequency and predictability are taken into account.