Leite Fábio P, Ratcliff Roger, White Corey N
Department of Psychology, Ohio State University, Columbus, Ohio 43210, USA.
Psychon Bull Rev. 2007 Oct;14(5):1007-9. doi: 10.3758/bf03194136.
Chen, Hale, and Myerson (2007) recently reported a test of the difference engine model (Myerson, Hale, Zheng, Jenkins, & Widaman, 2003). This test evaluated whether the standard deviation (SD) is proportional to the amount of processing-that is, mean reaction time (RT)--in a speeded cognitive task. We show that this evaluation is not a test of the model because its finding is a consequence of relationships in the data. We argue any model structure that produces increasing values of RT as a function of difficulty, with different slopes for different individuals, necessarily produces a correlation between SD and mean RT We illustrate this with a different model structure-that is, the diffusion model proposed by Ratcliff (1978)--showing that it produces a fan out between fast- and slow-group means and produces the correlation between SD and mean RT that matches the empirical result.
陈、黑尔和迈尔森（2007年）最近报告了对差异引擎模型的一项测试（迈尔森、黑尔、郑、詹金斯和威达曼，2003年）。该测试评估了在一项快速认知任务中，标准差（SD）是否与加工量成正比，即平均反应时（RT）。我们表明，这种评估并非对该模型的测试，因为其结果是数据中各种关系的产物。我们认为，任何一种随着难度增加而产生反应时增加值、且不同个体具有不同斜率的模型结构，必然会在标准差和平均反应时之间产生相关性。我们用一种不同的模型结构——即拉特克利夫（1978年）提出的扩散模型——对此进行说明，结果表明该模型在快速组和慢速组均值之间呈现扇形分布，并产生了与实证结果相符的标准差和平均反应时之间的相关性。
