Pupil dilation signals recognition salience

Area of Science:

• Cognitive Neuroscience
• Psychology
• Oculomotor Research

Background:

• Larger pupil dilations are observed for stimuli recognized from prior encounters compared to novel stimuli.
• The recognition dilation response (RDR) is hypothesized to stem from attentional orienting to recognition signals.
• Attentional orienting is influenced by motivational significance and expectation.

Purpose of the Study:

• To investigate the role of motivational significance and expectation in the recognition dilation response (RDR).
• To test whether the RDR is modulated by incentives and the sequential history of recognition judgments.
• To differentiate the RDR from late dilations related to feedback expectancy.

Main Methods:

• Two experiments manipulated incentives for 'old' versus 'new' judgments.
• The study analyzed the effects of runs of 'old' versus 'new' decisions on the RDR.
• Pupil dilation was measured as an indicator of cognitive and affective processing.

Main Results:

• Incentivizing 'new' judgments significantly reduced the RDR, while incentivizing 'old' judgments amplified it.
• The RDR was pronounced after sequences of 'new' decisions but minimal after sequences of 'old' decisions.
• A late dilation, distinct from the RDR, was linked to feedback expectancy.

Conclusions:

• The pupil dilation response reflects the perceived value and unexpectedness of recognition memory.
• The pupil serves as a dual signaling system, indicating both the salience of recognition evidence and feedback anticipation.
• The findings support an attentional orienting account of the RDR, separate from feedback processing.