Mamassian P, Goutcher R
Psychology Department, University of Glasgow, UK.
Cognition. 2001 Aug;81(1):B1-9. doi: 10.1016/s0010-0277(01)00116-0.
Visual perception is fundamentally ambiguous because an infinite number of three-dimensional scenes are consistent with our retinal images. To circumvent these ambiguities, the visual system uses prior knowledge such as the assumption that light is coming from above our head. The use of such assumptions is rational when these assumptions are related to statistical regularities of our environment. In confirmation of previous visual search experiments, we demonstrate here that the assumption on the illumination position is in fact biased to the above-left rather than directly above. This bias to the left reaches 26 degrees on average in a more direct shape discrimination task. Both right-handed and left-handed observers have a similar leftward bias. We discuss the possible origins of this singular bias on the illumination position.
视觉感知从根本上说是模糊的，因为无数个三维场景都与我们的视网膜图像相符。为了规避这些模糊性，视觉系统会运用先验知识，比如光从我们头顶上方照射下来的假设。当这些假设与我们环境的统计规律相关时，这种假设的运用就是合理的。为了证实先前的视觉搜索实验，我们在此证明，关于光照位置的假设实际上偏向于左上方而非正上方。在一个更直接的形状辨别任务中，这种向左的偏差平均达到26度。右利手和左利手的观察者都有类似的向左偏差。我们讨论了这种光照位置奇异偏差的可能来源。
