Reward modulates oculomotor competition between differently valued stimuli.

Area of Science:

• Cognitive Neuroscience
• Oculomotor Behavior
• Reward Processing

Background:

• The global effect paradigm studies visual attention when objects are in close spatial proximity.
• Previous research explored reward effects on attention, but often without direct competition between valued stimuli.

Purpose of the Study:

• To investigate how reward value influences oculomotor competition between simultaneously presented objects.
• To determine if previously learned reward associations bias eye movements even when rewards are no longer delivered.

Main Methods:

• A three-phase experiment: pre-training (baseline), reward-training (associating stimuli with high, low, or no reward), and post-training (rewards removed).
• Participants viewed two competing stimuli, and eye movements were tracked.
• Time course analysis examined the latency of reward effects on saccades.

Main Results:

• Initially, eye movements showed no bias.
• During reward training, saccades increasingly targeted high-reward stimuli.
• This bias persisted robustly in the post-training phase, indicating learning.
• Reward effects were evident in fast saccades (approx. 170 ms) and intensified with latency.

Conclusions:

• Reward associations significantly bias oculomotor competition, favoring stimuli previously linked to high rewards.
• Learned reward value affects even rapid, potentially habituated, oculomotor responses.
• This suggests reward learning plays a crucial role in how we select between competing visual stimuli.