Fig. 4.

The effects of reinforcer devaluation performed before (Test 1) and after (Test 2) the surgical disconnection had been completed. Difference scores (devaluation − baseline) for the control and disconnection group means are shown as bars, with the symbols representing scores of individual monkeys. Normal monkeys showed an enhancement of the devaluation effect in the second test, whereas operated monkeys showed a significant reduction of this effect in the second test. Op1,Filled diamonds; Op2, filled squares; Op3, filled inverted triangles; Op4, filled circles; Con1, open diamonds; Con2, open squares; Con3, open inverted triangles; Con4,open circle.