Zeljko Mick, Kritikos Ada, Grove Philip M
School of Psychology, The University of Queensland, Brisbane, Australia.
J Vis. 2019 May 1;19(5):7. doi: 10.1167/19.5.7.
Previous research suggests that cognitive factors acting in a top-down manner influence the perceptual interpretation of ambiguous stimuli. To examine the temporal unfolding of these influences as a perceptual decision evolves, we have implemented a modified version of the stream-bounce display. Our novel approach allows us to track responses to stream-bounce stimuli dynamically over the entire course of the motion sequence rather than collecting a subjective report after the fact. Using a trackpad, we had participants control a cursor to track a stream-bounce target actively from start to end and measured tracking speed throughout as the dependent variable. Our paradigm replicated the typical effect of visual-only displays being associated with a streaming bias and audiovisual displays with a bouncing bias. Our main finding is a significant behavioral change preceding a perceptual decision that then predicts that decision. Specifically, for trials in which the sound was presented, tracking speeds were significantly slower starting 500 ms before the point of coincidence and presentation of the sound for bounce compared to stream responses. We suggest that behavioral response may reflect a cognitive expectation of a perceptual outcome that then biases action and the interpretation of sensory input to favor that forthcoming percept in a manner consistent with both the predictive-coding and common-coding theoretical frameworks. Our approach provides a novel behavioral corroboration of recent imaging studies that are suggestive of early brain activity in perception and action.
先前的研究表明，以自上而下方式起作用的认知因素会影响对模糊刺激的感知解释。为了考察随着感知决策的发展这些影响在时间上的展开过程，我们采用了一种改良版的流反弹显示。我们的新方法使我们能够在运动序列的整个过程中动态跟踪对流反弹刺激的反应，而不是事后收集主观报告。我们让参与者使用触控板控制光标，从开始到结束主动跟踪流反弹目标，并将整个过程中的跟踪速度作为因变量进行测量。我们的范式重现了仅视觉显示与流偏向相关、视听显示与反弹偏向相关的典型效应。我们的主要发现是，在感知决策之前会出现显著的行为变化，而这种变化随后可以预测该决策。具体而言，在呈现声音的试验中，与流反应相比，在重合点和反弹声音呈现前500毫秒开始，跟踪速度明显更慢。我们认为，行为反应可能反映了对感知结果的认知预期，这种预期随后会使行动和感觉输入的解释产生偏差，从而以一种与预测编码和共同编码理论框架相一致的方式，偏向即将出现的感知。我们的方法为最近的成像研究提供了一种新的行为佐证，这些研究表明在感知和行动中存在早期大脑活动。
