Trommershäuser Julia, Maloney Laurence T, Landy Michael S
Department of Psychology, Center for Neural Science, New York University, New York, NY, USA.
Spat Vis. 2003;16(3-4):255-75. doi: 10.1163/156856803322467527.
We present a novel approach to the modeling of motor responses based on statistical decision theory. We begin with the hypothesis that subjects are ideal motion planners who choose movement trajectories to minimize expected loss. We derive predictions of the hypothesis for movement in environments where contact with specified regions carries rewards or penalties. The model predicts shifts in a subject's aiming point in response to changes in the reward and penalty structure of the environment and with changes in the subject's uncertainty in carrying out planned movements. We tested some of these predictions in an experiment where subjects were rewarded if they succeeded in touching a target region on a computer screen within a specified time limit. Near the target was a penalty region which, if touched, resulted in a penalty. We varied distance between the penalty region and the target and the cost of hitting the penalty region. Subjects shift their mean points of contact with the computer screen in response to changes in penalties and location of the penalty region relative to the target region in qualitative agreement with the predictions of the hypothesis. Thus, movement planning takes into account extrinsic costs and the subject's own motor uncertainty.
我们提出了一种基于统计决策理论对运动反应进行建模的新方法。我们首先提出一个假设，即受试者是理想的运动规划者，他们选择运动轨迹以最小化预期损失。我们推导了该假设在与特定区域接触会带来奖励或惩罚的环境中的运动预测。该模型预测，受试者的瞄准点会随着环境奖励和惩罚结构的变化以及执行计划运动时受试者不确定性的变化而发生偏移。我们在一项实验中测试了其中一些预测，在该实验中，如果受试者在规定时间内成功触摸电脑屏幕上的目标区域，就会得到奖励。目标附近有一个惩罚区域，如果触摸到该区域，就会受到惩罚。我们改变了惩罚区域与目标之间的距离以及触碰惩罚区域的代价。受试者会根据惩罚的变化以及惩罚区域相对于目标区域的位置，改变他们与电脑屏幕的平均接触点，这与假设的预测在定性上是一致的。因此，运动规划会考虑外在成本和受试者自身的运动不确定性。
