Measuring habit formation through goal-directed response switching.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Behavioral Science

Background:

• Reward-learning theory posits habits are stimulus-response links forged by extensive reward training.
• Animal studies show goal-directed actions become habitual with operant overtraining, but human research lacks a similar demonstration.
• This gap hinders translational models of behavior.

Purpose of the Study:

• To introduce response-time (RT) switch cost as a novel, reliable marker for the habit system in humans.
• To validate RT switch cost as a measure of habitual behavior.

Main Methods:

• Development of a new method to measure RT switch cost following operant training in humans.
• Experimental manipulation of overtraining, reward magnitude, and time pressure during the task.

Main Results:

• RT switch cost increased with task overtraining, indicating habit formation.
• Larger reward magnitudes led to increased RT switch cost.
• Added time pressure amplified RT switch cost, suggesting interference with the goal-directed system.

Conclusions:

• RT switch cost exhibits key properties expected of habitual behavior in humans.
• This finding provides a promising new avenue for investigating the human habit system.
• The results support the use of RT switch cost in translational research bridging animal and human studies of habit.