Is the Reversed Congruency Effect Observed with Gaze due to its Social Nature? Analysis of Non-Social Stimuli with Similar Asymmetrical Contrast Features of Eye-Gaze Stimuli

The reversed congruency effect (RCE), typically observed with gaze stimuli, reflects slower and less accurate responses to congruent than incongruent trials, in contrast to the standard congruency effect (SCE; faster for congruent than incongruent trials) observed with arrows. This phenomenon has been interpreted as evidence that gaze engages unique social and perceptual mechanisms. The present study examined whether the RCE could also be elicited with non-social stimuli designed to mimic the asymmetric contrast between pupil and sclera. Across two preregistered experiments, we manipulated the contrast polarity of arrow targets: in gaze-similar arrows, a darker arrowhead and lighter tail paralleled the pupil-sclera configuration, whereas in gaze-opposite arrows this relation was reversed. We also varied perceptual context by embedding stimuli in complex backgrounds. Both manipulations influenced response speed and accuracy, eliciting the SCE, with complex backgrounds producing slower, less accurate performance and reduced SCEs. Distributional analyses further revealed modulations of early response dynamics but no evidence of an RCE. Target-specific effects also emerged, with gaze-similar arrows harder to process yet eliciting smaller SCEs than gaze-opposite arrows. These findings suggest that contrast polarity and perceptual complexity alone are insufficient to reproduce gaze-induced RCEs, underscoring the unique role of gaze in spatial conflict resolution.Author note: Draft version 1, 01/10/25. This paper has not been peer reviewed.