Sign-tracking is an expectancy-mediated behavior that relies on prediction error mechanisms

Area of Science:

• Behavioral neuroscience
• Learning and memory
• Addiction research

Background:

• Appetitive Pavlovian conditioning can elicit sign-tracking (directed at the conditioned stimulus) and goal-tracking (directed at reward location).
• These behaviors are linked to addiction vulnerability and are hypothesized to involve distinct motivational and cognitive processes.
• Understanding their underlying associative mechanisms is crucial for clarifying their roles in behavior and potential clinical implications.

Purpose of the Study:

• To investigate whether sign-tracking and goal-tracking rely on similar or distinct associative learning mechanisms.
• To differentiate between incentive motivational and cognitive process accounts of these behaviors.
• To determine the role of prediction error mechanisms in the development of both behaviors.

Main Methods:

• Utilized illness-induced outcome devaluation to assess the role of reward expectancies in sign-tracking and goal-tracking.
• Employed Kamin blocking procedures to examine shared prediction error mechanisms across both behavioral types.
• Designed experiments where sign-tracking CSs were used to block goal-tracking CSs, and vice versa.

Main Results:

• Outcome devaluation significantly reduced sign-tracking, confirming its control by reward expectancies.
• Post-conditioned stimulus (CS) goal-tracking was also sensitive to outcome devaluation.
• Kamin blocking effects were observed in both directions (sign-tracking blocking goal-tracking, and goal-tracking blocking sign-tracking), indicating a common prediction error mechanism.

Conclusions:

• Sign-tracking and goal-tracking are both sensitive to outcome devaluation, supporting their basis in reward expectancies.
• The observation of Kamin blocking across both behaviors suggests a shared associative learning mechanism, specifically involving prediction errors.
• These findings challenge the notion of fundamentally distinct psychological processes underlying sign- and goal-tracking, suggesting greater overlap than previously assumed.