Direct Electrophysiological Mapping of Shape-Induced Affective Perception

Area of Science:

• Cognitive Neuroscience
• Affective Science
• Visual Perception

Background:

• Visual stimuli significantly influence affective perception and emotional responses.
• Unpleasant stimuli often evoke stronger emotional reactions than pleasant ones.
• While some shapes are anecdotally linked to emotions (e.g., triangle-negative, circle-positive), systematic investigation is lacking.

Purpose of the Study:

• To systematically investigate shape-induced affective perception using behavioral and electrophysiological measures.
• To map the degrees of affective valence associated with different shapes.
• To explore the relationship between stimulus valence and brain activity.

Main Methods:

• Utilized four distinct visual stimuli: ellipse, triangle, happy face, and angry face.
• Measured behavioral responses, specifically reaction time.
• Recorded electrophysiological responses, focusing on early event-related potential (ERP) components (P1, N1, P2, N2).

Main Results:

• Behaviorally, reaction times were significantly shorter for angry faces compared to other stimuli.
• Electrophysiologically, angry faces and triangles elicited larger P1, N1, P2, and N2 amplitudes than happy faces and ellipses, respectively.
• The P1 amplitude in the parietal lobe was strongest for angry faces, followed by happy faces, triangles, and ellipses.

Conclusions:

• Distinct electrophysiological patterns map shape-induced affective perception.
• Affective strain (e.g., unpleasant stimuli) results in larger ERP amplitudes than affective ease.
• Stronger affective stimuli elicit greater neural responses than milder ones, supporting the valence-intensity hypothesis.