School of Psychology, College of Social Science University of Lincoln Lincoln LN6 7TS, UK.
R Soc Open Sci. 2015 Dec 2;2(12):150418. doi: 10.1098/rsos.150418. eCollection 2015 Dec.
Prolonged exposure to visual stimuli causes a bias in observers' responses to subsequent stimuli. Such adaptation-induced biases are usually explained in terms of changes in the relative activity of sensory neurons in the visual system which respond selectively to the properties of visual stimuli. However, the bias could also be due to a shift in the observer's criterion for selecting one response rather than the alternative; adaptation at the decision level of processing rather than the sensory level. We investigated whether adaptation to implied motion is best attributed to sensory-level or decision-level bias. Three experiments sought to isolate decision factors by changing the nature of the participants' task while keeping the sensory stimulus unchanged. Results showed that adaptation-induced bias in reported stimulus direction only occurred when the participants' task involved a directional judgement, and disappeared when adaptation was measured using a non-directional task (reporting where motion was present in the display, regardless of its direction). We conclude that adaptation to implied motion is due to decision-level bias, and that a propensity towards such biases may be widespread in sensory decision-making.
长时间暴露于视觉刺激会导致观察者对后续刺激的反应产生偏差。这种适应引起的偏差通常可以用视觉系统中对视觉刺激的属性有选择性反应的感觉神经元的相对活动变化来解释。然而，这种偏差也可能是由于观察者选择一种反应而不是另一种反应的标准发生了变化；是在处理的决策层面而不是感觉层面上的适应。我们研究了对隐含运动的适应是最好归因于感觉层面还是决策层面的偏差。三个实验试图通过改变参与者的任务性质而保持感觉刺激不变来分离决策因素。结果表明，只有当参与者的任务涉及方向判断时，报告的刺激方向才会出现适应引起的偏差，而当使用非方向任务（报告显示中运动的存在位置，而不考虑其方向）来测量适应时，这种偏差就会消失。我们得出结论，对隐含运动的适应是由于决策层面的偏差，而这种偏向可能在感觉决策中普遍存在。
