Vickers D, Smith P
Perception. 1985;14(4):471-97. doi: 10.1068/p140471.
In a recent assessment of models of psychophysical discrimination, Heath criticises the accumulator model for its reliance on computer simulation and qualitative evidence, and contrasts it unfavourably with a modified random-walk model, which yields exact predictions, is susceptible to critical test, and is provided with simple parameter-estimation techniques. A counter-evaluation is presented, in which the approximations employed in the modified random-walk analysis are demonstrated to be seriously inaccurate, the resulting parameter estimates to be artefactually determined, and the proposed test not critical. It is pointed out that Heath's specific application of the model is not legitimate, his data treatment inappropriate, and his hypothesis concerning confidence inconsistent with experimental results. Evidence from adaptive performance changes is presented which shows that the necessary assumptions for quantitative analysis in terms of the modified random-walk model are not satisfied, and that the model can be reconciled with data at the qualitative level only by making it virtually indistinguishable from an accumulator process. A procedure for deriving exact predictions for an accumulator process is outlined.
在最近对心理物理辨别模型的评估中，希思批评累加器模型依赖计算机模拟和定性证据，并将其与修正的随机游走模型进行了不利对比。修正的随机游走模型能得出精确预测，易于进行严格检验，且具备简单的参数估计技术。本文给出了一项反评估，其中表明修正的随机游走分析中所采用的近似值严重不准确，由此得出的参数估计是人为确定的，且所提出的检验并不严格。指出希思对该模型的具体应用不合理，其数据处理不恰当，且他关于置信度的假设与实验结果不一致。文中给出了来自适应性性能变化的证据，表明根据修正的随机游走模型进行定量分析所需的假设不成立，并且该模型只有在使其与累加器过程几乎无法区分时，才能在定性层面与数据相符。概述了一种为累加器过程推导精确预测的程序。
