Table 2.

Three-way repeated-measures ANOVA of reward expectancy ratings

Factor	Mean square	F	Significance
Stage	0.233	F(1,17) = 0.320	0.579
Phase	13.498	F(1,17) = 18.622	0.000469
Stimulus	4.021	F(1,17) = 1.59	0.224
Stage × phase	0.274	F(1,17) = 0.437	0.518
Stage × stimulus	99.418	F(1,17) = 42.526	0.000005
Phase × Stimulus	0.341	F(1,17) = 0.627	0.439
Stage × phase × stimulus	11.724	F(1,17) = 8.951	0.008

There were no outliers in the data and the ratings were normally distributed, as assessed by inspection of a boxplot and Shapiro–Wilk’s test of normality (all p > 0.05). In this analysis, the assumption of sphericity for all three main factors (stage, phase, and stimulus) and their two- and three-way interactions was automatically met, because all these factors had only two levels. As shown above, there was a statistically significant three-way interaction between stage, phase, and stimulus (F_(1,17) = 8,961, p = 0.008). Bonferroni corrected post hoc tests comparing the difference in reward expectancy ratings between CS+ and CS− at each stage showed a significantly higher reward expectancy rating of color A compared to color B during late acquisition (p = 0.007). In the reversal stage, a significantly higher differential reward expectancy rating of the new CS+ versus the new CS− was observed (p = 0.017).