Stone Brian W, Tinker Jessica
Department of Psychology, University of Georgia, Athens, Georgia, United States of America.
PLoS One. 2016 Mar 9;11(3):e0150714. doi: 10.1371/journal.pone.0150714. eCollection 2016.
This paper reports on three experiments investigating the contribution of different sensory modalities to the tracking of objects moved in total darkness. Participants sitting in the dark were exposed to a brief, bright flash which reliably induced a positive visual afterimage of the scene so illuminated. If the participants subsequently move their hand in the darkness, the visual afterimage of that hand fades or disappears; this is presumably due to conflict between the illusory visual afterimage (of the hand in its original location) and other information (e.g., proprioceptive) from a general mechanism for tracking body parts. This afterimage disappearance effect also occurs for held objects which are moved in the dark, and some have argued that this represents a case of body schema extension, i.e. the rapid incorporation of held external objects into the body schema. We demonstrate that the phenomenon is not limited to held objects and occurs in conditions where incorporation into the body schema is unlikely. Instead, we propose that the disappearance of afterimages of objects moved in darkness comes from a general mechanism for object tracking which integrates input from multiple sensory systems. This mechanism need not be limited to tracking body parts, and thus we need not invoke body schema extension to explain the afterimage disappearance. In this series of experiments, we test whether auditory feedback of object movement can induce afterimage disappearance, demonstrate that the disappearance effect scales with the magnitude of proprioceptive feedback, and show that tactile feedback alone is sufficient for the effect. Together, these data demonstrate that the visual percept of a positive afterimage is constructed not just from visual input of the scene when light reaches the eyes, but in conjunction with input from multiple other senses.
本文报告了三项实验，这些实验研究了不同感官模态在追踪在完全黑暗中移动的物体时所起的作用。坐在黑暗中的参与者会暴露在一道短暂而明亮的闪光下，这可靠地诱发了被照亮场景的正性视觉后像。如果参与者随后在黑暗中移动他们的手，那只手的视觉后像就会变淡或消失；这大概是由于（手在其原始位置的）虚幻视觉后像与来自追踪身体部位的一般机制的其他信息（例如本体感觉）之间的冲突。这种后像消失效应在黑暗中移动的手持物体上也会出现，并且一些人认为这代表了身体图式扩展的一个例子，即快速将手持的外部物体纳入身体图式。我们证明，这种现象并不局限于手持物体，并且在不太可能纳入身体图式的条件下也会发生。相反，我们提出，在黑暗中移动的物体的后像消失来自于一个整合多个感官系统输入的物体追踪一般机制。这个机制不必局限于追踪身体部位，因此我们不必援引身体图式扩展来解释后像消失。在这一系列实验中，我们测试物体运动的听觉反馈是否能诱发后像消失，证明消失效应与本体感觉反馈的大小成比例，并表明仅触觉反馈就足以产生这种效应。总之，这些数据表明，正性后像的视觉感知不仅是由光线到达眼睛时场景的视觉输入构建的，而且还与来自其他多种感官的输入共同构建。
