Subtle Gaze and Pupil Dynamics: Detecting Recognition of Familiar Faces with Moving Serial Visual Presentation

Area of Science:

• Psychological Science
• Neuroscience
• Forensic Psychology

Background:

• Traditional concealed information tests (CIT) are vulnerable to countermeasures.
• Rapid serial visual presentation (RSVP) paradigms offer improved resilience.
• Pupil dilation in RSVP paradigms can indicate recognition of familiar information.

Purpose of the Study:

• Introduce a novel Moving Serial Visual Presentation (MSVP) paradigm.
• Enhance individual detection of familiar information using eye gaze and pupil dilation.
• Investigate involuntary recognition and goal-driven suppression of familiar information.

Main Methods:

• Developed MSVP combining serial visual presentation with lateral eye movements.
• Presented target, personally familiar (parent), and control faces in a visual stream.
• Experiment 1: Central fixation; Experiment 2: Free gaze with keypress response.
• Measured eye gaze, pupil dilation, and rate of pupil size change.

Main Results:

• Eye movement measures showed limited contribution to detecting familiar faces.
• Pupil dilation and its rate of change increased significantly in response to familiar faces.
• Classification based on pupil size change rate achieved 55.2% (Exp 1) and 33.3% (Exp 2) detection rates, surpassing prior RSVP methods (22.6%).

Conclusions:

• MSVP enhances the diagnostic value of pupil-based measures for detecting task-irrelevant familiarity, especially with constrained eye movements.
• The findings suggest MSVP is a promising advancement for concealed information testing.
• Further research is needed to meet applied standards for forensic use.