The reward positivity is insensitive to reinforcer devaluation

Area of Science:

• Neuroscience
• Cognitive Science
• Decision Making

Background:

• Behavioral adaptation relies on assessing reward outcomes relative to current motivational states.
• The reward positivity (RewP) is an electroencephalography (EEG) signal linked to reward value and motivation.
• It remains unclear if RewP reflects changes in reward value influenced by motivational state shifts.

Purpose of the Study:

• To investigate whether changes in the RewP signal are modulated by decreased reward value resulting from a change in motivational state.
• To examine the relationship between sensory-specific satiety, reward value inference, and the RewP.

Main Methods:

• Participants (n=31) underwent EEG recording while performing a modified Doors Task with Pavlovian conditioning.
• Food reinforcers (sweet and savory) were used, with one devalued through satiety via eating to fullness.
• Behavioral choices (win-stay/lose-switch) and RewP amplitudes were analyzed before and after reinforcer devaluation.

Main Results:

• Participants exhibited sensory-specific adjustments in food preferences post-devaluation, preferring the non-satiated food.
• Despite significant changes in perceived pleasantness and behavioral preferences, no significant differences in RewP amplitudes were detected.
• The RewP signal remained insensitive to the reinforcer devaluation manipulation.

Conclusions:

• The reward positivity (RewP) does not appear to track inferred changes in reward value driven by motivational state shifts (satiety).
• Affective and motivational factors, including inferences based on decreased reward value, did not modulate the RewP in this context.
• These findings challenge the notion that RewP solely reflects reward value updates influenced by internal states.