3.2 Cortisol concentrations
There was a significant main effect for group (F (1, 40) = 148.54,p < 0.001, ηp 2= 0.79). Cortisol was significantly higher in the stress group than in the control group. The main effect of time was significant (F (2, 80) = 28.16, p < 0.001,ηp 2 = 0.41); cortisol was significantly higher after the TSST (10.68 ± 5.13) than it was at baseline (6.09 ± 4.91) and after N-back tasks (7.4 ± 4.9). The interaction between group and time was also significant (F (2, 80) = 11.2, p < 0.001,ηp 2 = 0.22). Further analysis revealed that cortisol was significantly higher in the stress group after the TSST than at baseline (p < 0.001), but there were no significant differences between the two time points in the control group (p > 0.05).