Baldwin Joseph, Burleigh Alistair, Pepperell Robert, Ruta Nicole
School of Art & Design, Cardiff Metropolitan University, Cardiff, UK.
Iperception. 2016 Aug 17;7(4):2041669516661900. doi: 10.1177/2041669516661900. eCollection 2016 Jul-Aug.
Little is known about how we perceive the size and shape of objects in far peripheral vision. Observations made during an artistic study of visual space suggest that objects appear smaller and compressed in the periphery compared with central vision. To test this, we conducted three experiments. In Experiment 1, we asked participants to draw how a set of peripheral discs appeared when viewed peripherally without time or eye movement constraints. In Experiment 2, we used the method of constant stimuli to measure when a briefly presented peripheral stimulus appeared bigger or smaller compared with a central fixated one. In Experiment 3, we measured how accurate participants were in discriminating shapes presented briefly in the periphery. In Experiment 1, the peripheral discs were reported as appearing significantly smaller than the central disc, and as having an elliptical or polygonal contour. In Experiment 2, participants judged the size of peripheral discs as being significantly smaller when compared with the central disc across most of the peripheral field, and in Experiment 3, participants were quite accurate in reporting the shape of the peripheral object, except in the far periphery. Our results show that objects in the visual periphery are perceived as diminished in size when presented for long and brief exposures, suggesting diminution is an intrinsic feature of the structure of the visual space. Shape distortions, however, are reported only with longer exposures.
关于我们如何在远周边视觉中感知物体的大小和形状，我们了解得很少。在一项关于视觉空间的艺术研究中所做的观察表明，与中央视觉相比，物体在周边看起来更小且被压缩。为了验证这一点，我们进行了三项实验。在实验1中，我们要求参与者画出在没有时间或眼球运动限制的情况下，从周边观看时一组周边圆盘的样子。在实验2中，我们使用恒定刺激法来测量与中央注视的刺激相比，一个短暂呈现的周边刺激何时看起来更大或更小。在实验3中，我们测量了参与者辨别周边短暂呈现的形状的准确程度。在实验1中，参与者报告周边圆盘看起来明显比中央圆盘小，并且具有椭圆形或多边形轮廓。在实验2中，在大部分周边视野中，与中央圆盘相比，参与者判断周边圆盘的大小明显更小，并且在实验3中，除了极周边区域外，参与者在报告周边物体的形状方面相当准确。我们的结果表明，当长时间和短时间呈现时，视觉周边的物体在大小上被感知为缩小，这表明缩小是视觉空间结构的一个固有特征。然而，只有在较长时间曝光时才会报告形状扭曲。
