Attention's grasp: early and late hand proximity effects on visual evoked potentials

Abstract

Behavioral studies suggest that visual attention is biased toward stimuli in the region of space near the palm of the hand, but it is unclear whether this effect is universal or selective for goal/task-related stimuli. We examined event-related potentials (ERPs) using a visual detection task in which the hand was placed near or kept far from target and non-target stimuli that were matched for frequency and visual features to avoid confounding factors. Focusing on attention-sensitive ERP components, we found that P3 (350–450 ms) amplitudes were increased for Hand Near conditions for targets only, demonstrating a selective effect consistent with the P3's cross-modal and task-relevance influences. An N1 variant implicated in visuo-tactile integration (central Nd1; 120–190 ms) showed similar target-specific effects. P1 (80–110 ms) effects for target stimuli were also apparent, but may have applied to non-targets as well, which would be consistent with the P1's association with early, pre-categorical increases in sensory gain. Collectively, these findings suggest that by the time stimuli are categorized as relevant/irrelevant for action, the proprioceptive effects of the hand on visual attention are selective for goal/task-related stimuli. At the same time, hand proximity appears to bias attention early, starting with a facilitation of processing for perhaps any visual stimuli near the hand, and continuing with enhancements that are selective to those stimuli categorized as task-relevant.

Approach of visual stimuli modulates spatial expectations for subsequent somatosensory stimuli

“…Target stimuli presented near the hand were detected faster. Furthermore, they reported that the P3 amplitude increased for target stimuli presented near a hand (Reed et al, 2013). These results suggested that stimuli presented near the body constitute important information for us and that these stimuli are preferentially processed.…”

Phantoms on the hands: Influence of the body on brief synchiric visual percepts

“…Although our results do not seem to have a functional locus in the attentional system, we are not claiming that attentional accounts for improved visual performance near the hand are in error. One possibility, consistent with ERP work on the topic (Reed, Leland, Brekke, & Hartley, 2013), is that there may be multiple processes that contribute to enhanced visual processing around the body.…”

Visuotactile Peripersonal Space in Healthy Humans: Evidence from Crossmodal Congruency and Redundant Target Effects

“…If exogenous attentional cueing triggered by visual stimuli influences task performance only when the stimuli are presented within that range, this perspective might be an unlikely explanation for the current results. However, recent studies showed that there are attentional biases near the hands (e.g., [40,41]). This suggests a possibility that some attentional mechanisms involve the current phenomenon.…”

“…Regarding the attention deployment, the advantage for the lower visual field in visual performance was sometimes interpreted in terms of finely-tuned attention in the lower visual field [21]. Recent studies also showed that there are attentional biases near the hands (e.g., [40,41]). Furthermore, stimuli were presented in the near space in the three-fourth trials of a session.…”