Evidence for Model-Based Action Planning in a Sequential Finger Movement Task

ABSTRACT

In this article, the authors examine whether and how humans use model-free, reflexive strategies and model-based, deliberative strategies in motor sequence learning. They asked subjects to perform the grid-sailing task, which required moving a cursor to different goal positions in a 5 × 5 grid using different key-mapping (KM) rules between 3 finger keys and 3 cursor movement directions. The task was performed under 3 conditions: Condition 1, new KM; Condition 2, new goal position with learned KM; and Condition 3, learned goal position with learned KM; with or without prestart delay time. The performance improvement with prestart delay was significantly larger under Condition 2. This result provides evidence that humans implement a model-based strategy for sequential action selection and learning by using previously learned internal model of state transition by actions.

Keywords:

• action selection
• model-based
• model-free
• internal model
• reinforcement learning

ACKNOWLEDGMENTS

We thank Yuka Furukawa and Saori Tanaka for their help in data collection. The present research was supported by the Ministry of Education, Culture, Sports, Science and Technology grant no. 060613-06ER to A.F. and internal funding from the Okinawa Institute of Science and Technology.