Processing redundant signals: coactivation, divided attention, or what?

Area of Science:

• Cognitive Psychology
• Human Information Processing
• Visual Attention

Background:

• Redundancy gain in reaction time (RT) is observed when a target stimulus is presented in multiple modalities or locations.
• The current understanding of whether attention can be simultaneously directed to separate visual locations remains debated.

Purpose of the Study:

• To investigate the phenomenon of redundancy gain in reaction time (RT) under conditions of repeated visual targets.
• To examine the implications of redundancy gains for theories of visual attention, specifically regarding simultaneous attention to multiple locations.

Main Methods:

• Utilized a two-alternative forced-choice reaction time (RT) paradigm with two capital letters as target stimuli.
• Compared RTs across four conditions: single-target, repeated-target, target with noise, and both-targets presented simultaneously.

Main Results:

• Reaction time (RT) was fastest for single-target displays and slowest for displays with a target and a noise letter.
• No significant RT difference was found between repeated-target and both-targets conditions.
• Both repeated-target and both-targets conditions demonstrated a redundancy gain compared to the target-plus-noise condition.

Conclusions:

• The findings suggest that a unitary attentional focus, which processes visual information serially, effectively explains the observed pattern of results.
• The lack of response competition in the both-targets condition supports a model of focused, sequential processing rather than parallel processing of multiple targets.