Figure 2.

Sensitivity to outcome devaluation following long-term exposure to a palatable food. A, Mean (±SE) lever presses across days of instrumental training. Responding increased across days and there were no group differences in responding. B, Mean lever presses in a 5 min extinction test following prefeeding of the earned (devalued condition) or an alternative outcome (nondevalued condition). Control animals selectively decreased responding following the devalued condition compared with the nondevalued condition. Rats in the continuous-access group showed a numerically reduced but significant effect of devaluation. Rats in the restricted-access group responded similarly regardless of devaluation condition, indicating loss of sensitivity to changes in outcome value. Asterisk indicates p < 0.05. N = 12 per group.