Hierarchical schemas and goals in the control of sequential behavior.

Traditional accounts of sequential behavior assume that schemas and goals play a causal role in the control of behavior. In contrast, M. Botvinick and D. C. Plaut argued that, at least in routine behavior, schemas and goals are epiphenomenal. The authors evaluate the Botvinick and Plaut account by contrasting the simple recurrent network model of Botvinick and Plaut with their own more traditional hierarchically structured interactive activation model (R. P. Cooper & T. Shallice, 2000). The authors present a range of arguments and additional simulations that demonstrate theoretical and empirical difficulties for both Botvinick and Plaut's model and their theoretical position. The authors conclude that explicit hierarchically organized and causally efficacious schema and goal representations are required to provide an adequate account of the flexibility of sequential behavior.