Pupillary Responses to Faces Are Modulated by Familiarity and Rewarding Context

Area of Science:

• Neuroscience
• Cognitive Psychology
• Social Psychology

Background:

• Observing familiar and socially relevant faces activates the brain's reward circuit.
• Smiling faces are commonly used as social rewards in research.
• It remains unclear how familiarity and social relevance modulate face processing and if this depends on feedback context.

Purpose of the Study:

• To investigate whether familiarity and social relevance differentially modulate the processing of smiling faces.
• To determine if face processing depends on the feedback context (active vs. passive viewing).

Main Methods:

• Compared pupillary responses to smiling faces varying in familiarity and social relevance.
• Utilized both a passive viewing task and an active task (speeded visual short-term memory task).
• Collected behavioral ratings to assess perceived reward context.

Main Results:

• Pupillary responses were affected only in the active task and solely by subjective familiarity.
• Smaller pupil dilations were observed for more familiar faces, contrary to expectations.
• Behavioral ratings indicated a more rewarding context in the active task compared to the passive task.

Conclusions:

• Subjective familiarity plays a significant role in processing social rewards, influencing autonomic responses.
• The feedback context is critical in reward research; stimuli are more rewarding when performance-dependent.