Carnegie Mellon University
Carnegie Mellon University.
Psychol Sci. 2016 Sep;27(9):1215-26. doi: 10.1177/0956797616654912. Epub 2016 Jul 20.
To advance cognitive theory, researchers must be able to parse the performance of a task into its significant mental stages. In this article, we describe a new method that uses functional MRI brain activation to identify when participants are engaged in different cognitive stages on individual trials. The method combines multivoxel pattern analysis to identify cognitive stages and hidden semi-Markov models to identify their durations. This method, applied to a problem-solving task, identified four distinct stages: encoding, planning, solving, and responding. We examined whether these stages corresponded to their ascribed functions by testing whether they are affected by appropriate factors. Planning-stage duration increased as the method for solving the problem became less obvious, whereas solving-stage duration increased as the number of calculations to produce the answer increased. Responding-stage duration increased with the difficulty of the motor actions required to produce the answer.
为了推进认知理论，研究人员必须能够将任务的表现分解为其重要的心理阶段。在本文中，我们描述了一种新的方法，该方法使用功能磁共振成像（fMRI）脑激活来确定参与者在个体试验中何时处于不同的认知阶段。该方法结合多体素模式分析来识别认知阶段，并使用隐半马尔可夫模型来识别它们的持续时间。该方法应用于一个解决问题的任务，确定了四个不同的阶段：编码、规划、解决和响应。我们通过测试这些阶段是否受到适当因素的影响，来检查它们是否与赋予它们的功能相对应。随着解决问题的方法变得不那么明显，规划阶段的持续时间增加，而随着产生答案所需的计算数量的增加，解决阶段的持续时间增加。随着产生答案所需的运动动作的难度增加，响应阶段的持续时间增加。
