Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA.
Proc Natl Acad Sci U S A. 2012 Jan 3;109(1):333-8. doi: 10.1073/pnas.1111304109. Epub 2011 Dec 19.
According to various influential formal models of cognition, perceptual categorization and old-new recognition recruit the same memory system. By contrast, the prevailing view in the cognitive neuroscience literature is that separate neural systems mediate perceptual categorization and recognition. A direct form of evidence is that separate brain regions are activated when observers engage in categorization and recognition tasks involving the same types of stimuli. However, even if the same memory-based comparison processes underlie categorization and recognition, one would not expect to see identical patterns of brain activity across the tasks; the reason is that observers would adjust parameter settings (e.g., vary criterion settings) across the tasks to satisfy the different task goals. In this fMRI study, we conducted categorization and recognition tasks in which stimulus conditions were held constant, and in which observers were induced to vary hypothesized parameter settings across conditions. A formal exemplar model was fitted to the data to track the changes in parameters to help interpret the fMRI results. We observed systematic effects of changes in parameters on patterns of brain activity, which were interpretable in terms of differing forms of evidence accumulation that resulted from the changed parameter settings. After controlling for stimulus and parameter-related differences, we found little evidence that categorization and recognition recruit separate memory systems.
根据各种有影响力的认知形式模型，感知分类和新旧识别使用相同的记忆系统。相比之下，认知神经科学文献中的主流观点认为，感知分类和识别由独立的神经系统介导。直接证据是，当观察者参与涉及相同类型刺激的分类和识别任务时，会激活不同的大脑区域。然而，即使分类和识别基于相同的基于记忆的比较过程，也不应期望在任务之间看到完全相同的大脑活动模式；原因是观察者会根据不同的任务目标调整参数设置（例如，改变判别标准设置）。在这项 fMRI 研究中，我们进行了分类和识别任务，其中刺激条件保持不变，并且诱导观察者在不同条件下改变假设的参数设置。我们拟合了一个正式的范例模型来跟踪参数的变化，以帮助解释 fMRI 结果。我们观察到参数变化对大脑活动模式的系统影响，这些影响可以根据由于参数设置改变而导致的不同形式的证据积累来解释。在控制了刺激和参数相关差异后，我们几乎没有发现分类和识别使用独立的记忆系统的证据。
