Palanica Adam, Itier Roxane J
Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada.
Perception. 2017 Aug;46(8):941-955. doi: 10.1177/0301006616686989. Epub 2017 Jan 6.
Previous research has shown that gaze direction can only be accurately discriminated within parafoveal limits (∼5° eccentricity) along the horizontal visual field. Beyond this eccentricity, head orientation seems to influence gaze discrimination more than iris cues. The present study examined gaze discrimination performance in the upper visual field (UVF) and lower visual field (LVF), and whether head orientation affects gaze judgments beyond parafoveal vision. Direct and averted gaze faces, in frontal and deviated head orientations, were presented for 150 ms along the vertical meridian while participants maintained central fixation during gaze discrimination judgments. Gaze discrimination was above chance level at all but one eccentricity for the two gaze-head congruent conditions. In contrast, for the incongruent conditions, gaze was discriminated above chance only from -1.5° to +3°, with an asymmetry between the UVF and LVF. Beyond foveal vision, response rates were biased toward head orientation rather than iris eccentricity, occurring in the LVF for both head orientations, and in the UVF for frontal head views. These findings suggest that covert processing of gaze direction involves the integration of eyes and head cues, with congruency of these two social cues driving response differences between the LVF and the UVF.
先前的研究表明,沿水平视野,注视方向只能在中央凹旁视野范围内(约5°偏心率)被准确辨别。超过这个偏心率,头部朝向似乎比虹膜线索对注视辨别的影响更大。本研究考察了上视野(UVF)和下视野(LVF)中的注视辨别表现,以及头部朝向是否会影响中央凹旁视觉范围之外的注视判断。在参与者进行注视辨别判断时保持中央注视的情况下,以150毫秒的时长沿垂直子午线呈现正面和偏离头部朝向的直接注视和回避注视的面孔。在两种注视 - 头部一致的条件下,除了一个偏心率外,注视辨别都高于随机水平。相比之下,在不一致的条件下,注视仅在 -1.5°至 +3°之间能被辨别出高于随机水平,且上视野和下视野之间存在不对称性。在中央凹视觉范围之外,反应率偏向于头部朝向而非虹膜偏心率,在两种头部朝向的下视野以及正面头部视图的上视野中均是如此。这些发现表明,对注视方向的隐蔽加工涉及眼睛和头部线索的整合,这两种社会线索的一致性驱动了下视野和上视野之间的反应差异。