Preference bias during the training and test phases.

<p>(a) Time changes in the preference bias of individual 22 rats (gray lines) in the training phase (<i>left</i>) and the test phase (<i>right</i>). The yellow line indicates the means ± SEMs of 22 rats. (b) Same as (a), but they were aligned to the first session that reached the criterion. (c) Comparisons of the mean ± SEM preference biases during the training period, the during-learning period, and the post-learning period. The mean preference bias in the during-learning period was significantly lower than that in the training period and was significantly higher than that in the post-learning period. Training <i>versus</i> during-learning: <i>P =</i> 4.16 × 10⁻⁵, <i>Q</i>_3,63 = 6.66; during-learning <i>versus</i> post-learning: <i>P =</i> 5.59 × 10⁻⁶, <i>Q</i>_3,63 = 7.43; <i>P =</i> 1.12 × 10⁻¹³, <i>F</i>_2,63 = 49.7; Tukey's test after one-way ANOVA.