Shared mechanisms of presaccadic and exogenous attention in modulating visual perception of contrast

Different types of attention alter subjective visual perception in fundamentally distinct ways. Previous studies have focused on covert attention without concurrent eye movements, revealing that covert exogenous (involuntary) attention enhances contrast appearance of low-contrast stimuli while diminishing that of high-contrast stimuli, whereas covert endogenous (voluntary) attention uniformly enhances contrast appearance. However, the attentional effect preceding saccadic eye movements, a critical component of natural vision, remain understudied. Here, we found that when participants voluntarily initiated saccades, presaccadic attention enhanced the appearance of low-contrast stimuli while attenuating the appearance of high-contrast stimuli (Experiment 1, N = 29 adults). This pattern is surprisingly similar to exogenous attention but distinct from endogenous attention. Notably, the presaccadic attentional attenuation effect gradually accumulated during saccade preparation and remained positively correlated with the exogenous attentional effect (Experiment 2, N = 24 adults). Experiment 3 (N = 22 adults) replicated the positive correlation between presaccadic and exogenous attention, while finding no significant correlation between endogenous attention with either presaccadic or exogenous attention, implying the different underlying mechanism of covert endogenous attention with the other two types of attention. These findings suggest shared mechanisms between presaccadic and exogenous attention in shaping visual perception for the most basic-level visual feature, providing new insights into the relationship between eye movement and attention.