Preserved discrimination sensitivity to looming trajectories across parafoveal and peripheral vision

Detailed perceptual discrimination is suggested to be inferior in peripheral vision, with sensitivity declining continuously as retinal eccentricity increases. Yet most ecologically relevant events, including imminent threats, are first signaled in the periphery, raising the possibility that peripheral capabilities for threat processing have been underestimated. Here, we tested whether peripheral vision preserves discrimination sensitivity to the trajectories of looming stimuli-visual patterns simulating collision-which are known to engage rapid subcortical visual pathways with large receptive fields. Across five psychophysical experiments in desktop and virtual reality (VR) settings, we consistently found that discrimination sensitivity for looming stimuli remained stable from parafoveal to near-peripheral eccentricities (2° to 14.5°) and declined only at the far periphery (30°). In contrast, physically matched receding stimuli showed typical eccentricity-dependent decline, ruling out general motion sensitivity as the source of preserved performance. Pupil responses further supported the affective salience of looming stimuli. These findings suggest that peripheral vision may be selectively optimized for detecting biologically relevant threats via subcortical mechanisms, challenging the traditional fovea-centered view of visual discrimination.