The Timing of Gaze Direction Perception: ERP Decoding and Task Modulation

Area of Science:

• Cognitive Neuroscience
• Social Neuroscience
• Visual Perception

Background:

• Gaze direction provides vital social cues about attention and intentions.
• Event-related potentials (ERPs) using electroencephalography (EEG) study temporal dynamics of gaze processing.
• The precise timing of gaze direction discrimination, independent of other facial cues, remains unclear.

Purpose of the Study:

• To investigate the time course of gaze direction processing.
• To determine when the brain distinguishes gaze direction irrespective of head orientation.
• To explore the influence of task relevance on gaze direction decoding.

Main Methods:

• Utilized an event-related potential (ERP) decoding approach combining support vector machine and error-correcting output codes.
• Recorded EEG data from young healthy adults performing either a gaze direction detection or a face orientation task.
• Presented 3D realistic faces with varying head and gaze orientations (±30°, ±15°, 0°).

Main Results:

• ERP decoding analyses indicated gaze direction discrimination began at 140 ms (gaze detection task) and 120 ms (face orientation task).
• Decoding accuracy for gaze direction was higher in the gaze detection task compared to the face orientation task.
• Direct gaze yielded the highest decoding accuracy in both tasks, suggesting enhanced processing.

Conclusions:

• Gaze direction processing is initiated earlier than suggested by classical ERP analyses.
• Task relevance significantly modulates the latency and accuracy of gaze direction decoding.
• Brain pattern decoding is sensitive to the relevance of visual social cues.