Publications

Abstract

Eye gaze is a powerful ostensive cue in infant-caregiver interactions, with demonstrable effects on language acquisition. While the link between gaze following and later vocabulary is well-established, the effects of eye gaze on other aspects of language, such as speech processing, are less clear. In this EEG study, we examined the effects of the speaker’s eye gaze on ten-month-old infants’ neural tracking of naturalistic audiovisual speech, a marker for successful speech processing. Infants watched videos of a speaker telling stories, addressing the infant with direct or averted eye gaze. We assessed infants’ speech-brain coherence at stress (1–1.75 Hz) and syllable (2.5–3.5 Hz) rates, tested for differences in attention by comparing looking times and EEG theta power in the two conditions, and investigated whether neural tracking predicts later vocabulary. Our results showed that infants’ brains tracked the speech rhythm both at the stress and syllable rates, and that infants’ neural tracking at the syllable rate predicted later vocabulary. However, speech-brain coherence did not significantly differ between direct and averted gaze conditions and infants did not show greater attention to direct gaze. Overall, our results suggest significant neural tracking at ten months, related to vocabulary development, but not modulated by speaker’s gaze.

Abstract

Native speakers of Dutch do not always adhere to prescriptive grammar rules in their daily speech. These grammatical norm violations can elicit emotional reactions in language purists, mostly high-educated people, who claim that for them these constructions are truly ungrammatical. However, linguists generally assume that grammatical norm violations are in fact truly grammatical, especially when they occur frequently in a language. In an fMRI study we investigated the processing of grammatical norm violations in the brains of language purists, and compared them with truly grammatical and truly ungrammatical sentences. Grammatical norm violations were found to be unique in that their processing resembled not only the processing of truly grammatical sentences (in left medial Superior Frontal Gyrus and Angular Gyrus), but also that of truly ungrammatical sentences (in Inferior Frontal Gyrus), despite what theories of grammar would usually lead us to believe

Abstract

Superiority in visual search for individuals diagnosed with autism spectrum disorder (ASD) is a well-reported finding. We administered two visual search tasks to individuals with ASD and matched controls. One showed no difference between the groups, and one did show the expected superior performance for individuals with ASD. These results offer an explanation, formulated in terms of load theory. We suggest that there is a limit to the superiority in visual search for individuals with ASD, related to the perceptual load of the stimuli. When perceptual load becomes so high that no additional task-(ir)relevant information can be processed, performance will be based on single stimulus identification, in which no differences between individuals with ASD and controls have been demonstrated