视觉搜索任务中直视探测优势的眼动研究

已有研究发现在视觉搜索任务中对直视的探测比斜视更快且更准确, 该现象被命名为“人群中的凝视效应”。大多数研究者将该效应的产生归因于直视会捕获更多的注意。然而, 直视条件下对搜索项的匹配加工更容易也有可能导致对直视的探测比斜视快。此外,已有研究还发现头的朝向会影响对注视方向的探测, 但对于其产生原因缺乏实验验证。本研究采用视觉搜索范式, 运用眼动技术, 把注视探测的视觉搜索过程分为准备阶段、搜索阶段和反应阶段, 对这两个问题进行了探讨。结果显示：对直视的探测优势主要表现在搜索阶段和反应阶段; 在搜索阶段直视的探测优势获益于搜索路径的变短和分心项数量的变少以及分心项平均注视时间的变短; 头的朝向仅在搜索阶段对注视探测产生影响。该结果表明, 在直视探测中对搜索项的匹配加工比在斜视探测中更容易也是导致“人群中的凝视效应”的原因之一; 头的朝向仅仅影响了对注视方向的搜索并没有影响对其的确认加工。

The Detection Superiority of Perceived Direct Gaze in Visual Search Task:Evidence from Eye Movements

Previous studies have reported that a straight gaze target embedded in averted gaze distracters was detected faster and more accurate than an averted gaze target among straight gaze distracters.The phenomenon of detection superiority of perceived direct gaze was termed as "the stare-in-the-crowd effect"."The stare-in-the-crowd effect" could be explained as that a straight gaze captures visual-spatial attention more effectively than an averted gaze.However,it is also possible that the stimulus items matching process under the direct gaze condition is faster and easier than that under the averted gaze condition.This explanation has not been tested in previous studies.In addition,head orientation was found to be able to affect the detection of gaze direction.However,it is not clear how head orientation affectsthe detection of gaze direction.In view of this,we used eye tracking approach and divided the detection of gaze direction into three behavioral epochs: the preparation,search and response epoch.To investigate: (1) in which epoch the detection advantage of the direct gaze occurred,and whether the more effectiveness of stimulus items matching process under the direct gaze condition contributed to the-stare-in-the-crowd effect,along with the capture visual-spatial attention of direct gaze.(2) How head orientation affected the detection of gaze direction,and in which visual search epoch this effect was mainly manifested.We used a visual search task.The experiment consisted of two factors: gaze direction (direct gaze;averted gaze) and head orientation (frontal head;deviated head).Subjects were instructed to detect as accurately and quickly as possible whether the target gaze direction was present or not.Sixteen volunteers participated in the experiment (6 males and 10 females).Behavioral results showed that the direct gaze targets were detected more rapidly and accurately than the averted gaze targets;Eye movement analysis found: the detection advantage of direct gaze mainly occurred in the search and response epochs;the effect of head orientation on detection of gaze direction was only manifested in search epoch;the direct gaze targets were detected more rapidly than the averted gaze targets in deviated head condition and the direct gaze targets were detected more slowly than the averted gaze targets in the frontal head condition.The results showed that the detection advantage for direct gaze occurred in both the search and response epochs.The superiority of direct gaze was due to both the more effective capture of visual-spatial attention and the more effectiveness of stimulus items matching process in direct gaze.In addition,the effect of head orientation on the detection of gaze directionwas limited,head orientation only affected the search process of gaze direction,but not the confirm process of targets.