Sensitivity to syntax in visual cortex

Abstract

One of the most intriguing findings on language comprehension is that violations of syntactic predictions can affect event-related potentials as early as 120 ms, in the same time-window as early sensory processing. This effect, the so-called early left-anterior negativity (ELAN), has been argued to reflect word category access and initial syntactic structure building (Friederici, 2002). In two experiments, we used magnetoencephalography to investigate whether (a) rapid word category identification relies on overt category-marking closed-class morphemes and (b) whether violations of word category predictions affect modality-specific sensory responses. Participants read sentences containing violations of word category predictions. Unexpected items varied in whether or not their word category was marked by an overt function morpheme. In Experiment 1, the amplitude of the visual evoked M100 component was increased for unexpected items, but only when word category was overtly marked by a function morpheme. Dipole modeling localized the generator of this effect to the occipital cortex. Experiment 2 replicated the main results of Experiment 1 and eliminated two non-morphology-related explanations of the M100 contrast we observed between targets containing overt category-marking and targets that lacked such morphology. Our results show that during reading, syntactically relevant cues in the input can affect activity in occipital regions at around 125 ms, a finding that may shed new light on the remarkable rapidity of language processing.

Early Occipital Sensitivity to Syntactic Category Is Based on Form Typicality

“…Psycholinguistic research has also shown that closed class morphemes have a special status in language processing (e.g., Bradley, 1983). Consistent with the hypothesis that the M100 category effect is dependant on the presence of closed class morphemes, in Dikker et al (2009) we only found an M100 effect when the category of the unexpected item was saliently marked by a closed-class morpheme.…”

“…Typical vs. Neutral) within-subjects ANOVA on the mean amplitude of a 15ms interval centered around the average M100 peak for each condition and subject, as in Dikker et al (2009). Post-hoc ttests were used to examine effects within each noun type.…”

Wait a second! delayed impact of argument roles on on-line verb prediction

“…For example, listeners are more likely to direct their eye-gaze to a picture of an edible object (e.g., a cake) when they hear the beginning of an utterance like 'The boy will eat…' compared to a neutral utterance such as 'The boy will move…' (Altmann & Kamide, 1999). Further, much evidence has suggested that comprehenders compute rich expectations about upcoming inputs at multiple levels of representation (syntactic: Ilkin & Sturt, 2011;Lau, Stroud, Plesch, & Phillips, 2006;Levy, Fedorenko, Breen, & Gibson, 2012;Omaki et al, 2015;Staub & Clifton, 2006;Wicha et al, 2004;Van Berkum et al, 2005;Yoshida, Dickey, & Sturt, 2013;lexico-semantic: Federmeier & Kutas, 1999;Kutas & Hillyard, 1984;Otten & Van Berkum, 2008;Szewczyk & Schriefers, 2013; phonological and orthographic: Delong et al, 2005;Dikker, Rabagliati, Farmer, & Pylkkanen, 2010;Dikker, Rabagliati, & Pylkkänen, 2009;Farmer, Yan, Bicknell, & Tanenhaus, 2015;Kim & Lai, 2012;Laszlo & Federmeier, 2009). Here, we operationally define 'prediction' as the pre-activation of stored representations before the bottom-up input is encountered, and we will make no a priori assumptions regarding the nature of the mechanisms involved (e.g., whether they are automatic or controlled).…”

The importance of awareness for understanding language

“…One alternative interpretation argues that these early components instead index mismatches between predicted sensory input and actual sensory input (e.g., the wordform by is visually surprising in a context in which a noun was expected, because this wordform is only used as a preposition, Dikker, Rabagliati, Farmer, & Pylkkänen, 2010;Dikker, Rabagliati, & Pylkkänen, 2009;Kim & Lai, 2012); under this account, the ERP response to by does not reflect combinatorial syntactic processing, but a sensory prediction error. A second, more deflationary account, has argued that early ERP responses to ungrammatical words might also result from artefacts caused by how ERP data are baseline corrected (Steinhauer & Drury, 2012).…”