Cross-modal influences on attentional asymmetries: Additive effects of attentional orienting and arousal

- Infrequent distractors to the right ear decrease attentional asymmetries.
- Right distractors increase hemispheric activation and speed RTs for left-responders.
- Left distractors increase hemispheric activation and speed RTs for right-responders.
- Non-spatial, highly salient, auditory distractors decrease asymmetries.
- Orienting & arousal effects are additive, with orienting effects being stronger.

Attention is asymmetrically distributed across the visual field, such that left side stimuli are more salient, which causes a spatial bias known as pseudoneglect. Although auditory cues can be used to direct visual attention to a location, the influence of auditory distractors on visuospatial asymmetries remains unknown. We examined whether attentional orienting or arousal effects occur when either left or right auditory distractors are presented during the landmark task. We also categorised participants based on the baseline direction of pseudoneglect. Experiment 1 showed a strong attentional orienting effect. A slightly weaker arousal effect was also observed. Interestingly, these effects appear to be additive, such that infrequent right ear distractors rendered leftward biases non-significant. A second experiment, using centralised auditory distractors, was conducted to isolate the role of arousal. A strong arousal effect occurred, which was mediated by baseline direction of pseudoneglect. Left- and right-responders showed parallel decreases in the strength of attentional asymmetries, as biases decreased in the presence of distractors. Importantly, these decreases were not accompanied by an increase in accuracy. We conclude that both attentional orienting and arousal mechanisms contribute to the cross-modal integration of auditory and visual information during visuospatial processing, with the role of attentional orienting being more dominant.