Motivating operations as contexts for operant discrimination training and testing

Two groups of mice were exposed to stimulus discrimination training and testing under different motivational conditions to study interactions between motivating operations (MOs) during initial discrimination training and MOs when performance is tested following training. One group received all discrimination training sessions under 24-h food deprivation while the other received all sessions under 0-h food deprivation. The number of responses allowed during discrimination training sessions was limited such that the two groups experienced the same number of response-outcome contingencies. The groups then received two post-discrimination training tests: one conducted under 24-h food deprivation and the other conducted under 0-h food deprivation. Results indicated no difference between groups in terms of discrimination ratio. However, subjects trained under 24-h deprivation made more responses in the 24-h test, while subjects trained under 0-h deprivation made more responses in the 0-h test. These results are discussed in terms of motivational state-dependent learning.