Interference of Illusory Contour Perception by a Distractor.

Junkai Yang,Qian Wu,Xiaolin Mei,Xiang Wu,Lisen Sui,Hongyuan Wu

doi:10.3389/fpsyg.2021.526972

Abstract

The visual system is capable of recognizing objects when object information is widely separated in space, as revealed by the Kanizsa-type illusory contours (ICs). Attentional involvement in perception of ICs is an important topic, and the present study examined whether and how the processing of ICs is interfered with by a distractor. Discrimination between thin and short deformations of an illusory circle was investigated in the absence or presence of a central dynamic patch, with difficulty of discrimination varied in three levels (easy, medium, and hard). Reaction time (RT) was significantly shorter in the absence compared to the presence of the distractor in the easy and medium conditions. Correct rate (CR) was significantly higher in the absence compared to the presence of the distractor in the easy condition, and the magnitude of the difference between CRs of distracted and non-distracted responses significantly reduced as task difficulty increased. These results suggested that perception of ICs is more likely to be vulnerable to distraction when more attentional resources remain available. The present finding supports that attention is engaged in perception of ICs and that distraction of IC processing is associated with perceptual load.

Highlights

One of the essential functions of the visual system is to recognize objects even when object information is widely separated in space, as revealed by the well-known Kanizsa-type illusory contours (ICs) in which a contour is perceived despite the fragments of the contour being separated by gaps (Kanizsa, 1976; Figure 1A).Because the Kanizsa-type IC appears to be perceived effortlessly, it has been considered to arise from pre-attentive or automatic processes
The Correct rate (CR) cost was not significant in all the three task difficulty levels in the control real contours (RCs) task, whereas in the IC task, a significant CR cost was observed in the easy condition and the magnitude of the CR cost significantly reduced as task difficulty increased
The results showed a significant Reaction time (RT) cost in the easy and medium conditions and a significant CR cost in the easy condition, and the magnitude of the CR cost significantly reduced as task difficulty increased

Summary

Introduction

One of the essential functions of the visual system is to recognize objects even when object information is widely separated in space, as revealed by the well-known Kanizsa-type illusory contours (ICs) in which a contour is perceived despite the fragments of the contour being separated by gaps (Kanizsa, 1976; Figure 1A).Because the Kanizsa-type IC appears to be perceived effortlessly, it has been considered to arise from pre-attentive or automatic processes. In a seminal work by Davis and Driver (1994) using a visual search task, an IC figure among non-IC figures was found to be detected in parallel without requirement of attention. Using a multiple object tracking task, it was found that the task performance was impaired when ICs were formed by targets and distractors, and was improved when ICs were formed by targets (Keane et al, 2011). This suggests that the IC is formed and directs attention automatically

Methods

Results

Conclusion