Palmer John, Huk Alexander C, Shadlen Michael N
Department of Psychology, University of Washington, Seattle, WA, USA.
J Vis. 2005 May 2;5(5):376-404. doi: 10.1167/5.5.1.
Both the speed and the accuracy of a perceptual judgment depend on the strength of the sensory stimulation. When stimulus strength is high, accuracy is high and response time is fast; when stimulus strength is low, accuracy is low and response time is slow. Although the psychometric function is well established as a tool for analyzing the relationship between accuracy and stimulus strength, the corresponding chronometric function for the relationship between response time and stimulus strength has not received as much consideration. In this article, we describe a theory of perceptual decision making based on a diffusion model. In it, a decision is based on the additive accumulation of sensory evidence over time to a bound. Combined with simple scaling assumptions, the proportional-rate and power-rate diffusion models predict simple analytic expressions for both the chronometric and psychometric functions. In a series of psychophysical experiments, we show that this theory accounts for response time and accuracy as a function of both stimulus strength and speed-accuracy instructions. In particular, the results demonstrate a close coupling between response time and accuracy. The theory is also shown to subsume the predictions of Piéron's Law, a power function dependence of response time on stimulus strength. The theory's analytic chronometric function allows one to extend theories of accuracy to response time.
知觉判断的速度和准确性都取决于感觉刺激的强度。当刺激强度高时，准确性高且反应时间快；当刺激强度低时，准确性低且反应时间慢。虽然心理测量函数作为分析准确性与刺激强度之间关系的工具已得到充分确立，但反应时间与刺激强度之间关系的相应计时函数却没有得到同样多的关注。在本文中，我们描述了一种基于扩散模型的知觉决策理论。在该理论中，决策基于感觉证据随时间的累加直至达到一个界限。结合简单的缩放假设，比例率扩散模型和幂率扩散模型预测了计时函数和心理测量函数的简单解析表达式。在一系列心理物理学实验中，我们表明该理论能够解释反应时间和准确性作为刺激强度和速度 - 准确性指令的函数。特别是，结果表明反应时间和准确性之间存在紧密的耦合关系。该理论还被证明包含了皮埃龙定律的预测，即反应时间对刺激强度的幂函数依赖性。该理论的解析计时函数使人们能够将准确性理论扩展到反应时间。
