Stronger interference from distractors in the right hemifield during visual search

Area of Science:

• Cognitive Neuroscience
• Visual Perception
• Human Attention

Background:

• The orientation-bias hypothesis suggests a right visual hemifield (RVF) attention bias during spatial competition.
• Previous studies reported conflicting findings, with some showing RVF bias and others showing left visual hemifield (LVF) bias in rapid serial visual presentation (RSVP) tasks.

Purpose of the Study:

• To investigate the discrepancy in visual attention biases observed in different experimental paradigms.
• To determine if distractor features (color vs. orientation) explain the conflicting results regarding RVF/LVF attention biases.

Main Methods:

• Employed the additional singleton paradigm with color and orientation distractors.
• Compared interference effects for targets and distractors in the left and right visual hemifields.
• Differentiated between bottom-up (singleton) and top-down (feature) search strategies.

Main Results:

• Color distractors showed greater interference with contralateral targets in the RVF than LVF.
• This RVF advantage disappeared when searching for a color target, indicating a shift in bias.
• Asymmetrical interference patterns differed based on whether search was bottom-up or top-down.

Conclusions:

• The left visual hemifield (LVF) orienting bias appears specific to bottom-up saliency-driven search (singleton search).
• Attentional asymmetry depends on task demands, specifically spatial vs. temporal competition and search type (bottom-up vs. top-down).
• Findings reconcile conflicting results by highlighting the role of distractor features and search strategy in visual attention biases.