Explicit knowledge of task structure is a primary determinant of human model-based action.

Area of Science:

• Cognitive Neuroscience
• Decision-Making Science

Background:

• Human choice behavior is shaped by explicit instruction, but its effect on complex decision-making systems (model-based vs. model-free) remains unclear.
• Model-free systems generate habitual actions, while model-based systems enable goal-directed behavior through predictions.

Purpose of the Study:

• To investigate how explicit task information influences model-based and model-free control in a complex decision-making task.
• To compare the effects of instruction versus experience in acquiring task knowledge across different participant groups.

Main Methods:

• Assessed behavior in a complex decision-making task before and after providing explicit information about task structure.
• Included healthy volunteers and individuals with obsessive-compulsive disorder (OCD).
• Analyzed the emergence of model-based control with experience and instruction.

Main Results:

• Initial behavior was predominantly model-free, with rewards reinforcing actions directly.
• Model-based control emerged in a minority of participants with experience, and less so in those with OCD.
• Providing explicit task structure information significantly enhanced model-based control across all participant groups.

Conclusions:

• Explicit task structural knowledge is a primary driver of model-based reinforcement learning in humans.
• Instruction is a more effective method for acquiring task knowledge than experience.
• Understanding these mechanisms has implications for cognitive disorders like OCD.