Comparing Eye-tracking Data of Children with High-functioning ASD, Comorbid ADHD, and of a Control Watching Social Videos.

Children with autism spectrum disorders (ASD) are known to have sensory-perceptual processing deficits that weaken their abilities to attend and perceive social stimuli in daily living contexts. Since daily social episodes consist of subtle dynamic changes in social information, any failure to attend to or process subtle human nonverbal cues, such as facial expression, postures, and gestures, might lead to inappropriate social interaction. Traditional behavioral rating scales or assessment tools based on static social scenes have limitations in capturing the moment-to-moment changes in social scenarios. An eye-tracking assessment, which can be administered in a video-based mode, is therefore preferred, to augment clinical observation. In this study, using the single-case comparison design, the eye-tracking data of three participants, a child with autism spectrum disorder (ASD), another with comorbid attention deficit-hyperactive disorder (ADHD), and a neurotypical control, are captured while they view a video of social scenarios. The eye-tracking experiment has helped answer the research question: How does social attention differ between the three participants? By predefining areas of interest (AOIs), their visual attention on relevant or irrelevant social stimuli, how fast each participant attends to the first social stimuli appearing in the videos, for how long each participant continues to attend to those stimuli within the AOIs, and the gaze shifts between multiple social stimuli appearing concurrently in the same social scene are captured, compared, and analyzed in a video-based eye-tracking experiment.

Conflict monitoring in multi-sensory flanker tasks: Effects of cross-modal distractors on the N2 component.

The N2 component is a well-known neural correlate of conflict monitoring (CM), being more negative in the presence of conflicting information in visual conflict tasks. However, whether to-be-ignored auditory distractors can introduce additional conflict remains unknown. In the present work, subjects performed a visual (V) and audiovisual (AV) version of a Go/NoGo flanker task, and responded only if the target arrow pointed toward a pre-specified direction (e.g., left). In the AV task, in which to-be-ignored auditory distractors that were semantically associated with the flankers were concurrently presented, the congruency effect on both RT and N2 amplitude was enhanced, confirming that additional conflict can be brought about by cross-modal distractors at both behavioural and neural levels. Consistent with the hypothesis that N2 amplitude reflects response conflict in visual conflict tasks, within-subject correlation between N2 amplitude and RT was significant in the Go conditions for the V task (congruent/incongruent). However, for the AV task, the correlation was significant only in the congruent condition. These findings suggest that while the cross-modal conflict is registered by the CM process, only part of this conflict could effectively induce response conflict.

Aspectual asymmetries in the mental representation of events: Role of lexical and grammatical aspect.

Temporal information is important in the construction of situation models, and many languages make use of perfective and imperfective aspect markers to distinguish between completed situations (e.g., He made a cake) and ongoing situations (e.g., He is making a cake). Previous studies in which the effect of grammatical aspect has been examined have shown that perfective sentences are often processed more quickly than imperfective ones (e.g., Chan, Yap, Shirai, & Matthews, 2004; Madden & Zwaan, 2003; Yap et al., 2004; Yap et al., 2006). However, these studies used only accomplishment verbs (i.e., verbs with an inherent endpoint, such as bake a cake). The present study on the processing of Cantonese includes activity verbs (i.e., durative verbs with no inherent endpoint, such as play the piano), and the results indicate a strong interaction between lexical aspect (i.e., verb type) and grammatical aspect. That is, perfective sentences were processed more quickly with accomplishment verbs, consistent with previous findings, but imperfective sentences were processed more quickly with activity verbs. We suggest that these different aspectual asymmetries emerge as a result of the inherent associations between accomplishment verbs and the bounded features of perfective aspect and between activity verbs and the unbounded features of imperfective aspect. The sentence stimuli from this study may be downloaded from mc.psychonomic-journals.org/content/supplemental.