Abstract
Previous studies have found two main interactions between foveal and peripheral stimuli. First, it has been shown that pre-saccadic peripheral information is encoded and integrated with post-saccadic foveal information. Second, foveal information has a modulating role for perception of peripheral stimuli in a feedback fashion (Williams et al., 2008). Specifically, this foveal feedback effect is proposed to occur approximately 100ms following the onset of the peripheral stimulus (Weldon, 2016; Yu & Shim, 2016). However, functional roles of this effect have been inconsistent; the presence of a foveal distractor has been shown to both facilitate and impair peripheral perception in discrimination tasks. To resolve this discrepancy, in three experiments we tested the role of target-distractor similarity with a color report task where participants were asked to report the color of the peripheral target while ignoring the foveal distractor. We used three different types of distractors: the distractor shared all the features with the target (match), varied along the color feature (no-match), or did not share any feature with the target (control). As in previous studies, we also manipulated target-distractor SOAs. Contrary to the previous findings, merely presenting a foveal distractor did not have a significant effect on the perception of the peripheral object. Specifically, color reports were accurate for match and control conditions, regardless of the SOA. Instead, we found that the target-distractor similarity significantly affects color reports; reports of the peripheral target's feature were shifted toward the foveal distractor's feature in the no-match condition. This effect was further modulated by the target-distractor SOA, such that these shifts were only seen for negative SOAs where the foveal distractor was presented before the target object. These results contradict the foveal feedback hypothesis and instead support a feed-forward integration account of peripheral perception.
Meeting abstract presented at VSS 2018