Figure 4.

The mean number of trials (±S.E.M.) to reach a criterion of 26 of 32 trials correct across four sessions in the acquisition phases of Experiments 1 and 2. The results of Experiment 1 are shown on the left and the results of Experiment 2 are shown on the right. In Experiment 1 hippocampal lesioned mice (HPC) reached criterion in significantly fewer trials than sham lesioned mice (Sham). Also, mice in Group Constant reached criterion in fewer trials than mice in Group Inconstant. In Experiment 2 mice were trained on the Constant condition. Once again hippocampal lesioned mice reached criterion in fewer trials than sham lesioned mice.