Moreover, we found a very small effect of difficulty on the move quality; this suggests that the capacity to detect good from bad edges is nearly independent of the instances considered in our experiment.
There was no effect of difficulty on omission errors, nor was there a group by difficulty interaction (P > 0.5).
A repeated-measures analysis of variance (ANOVA) revealed a significant main effect of difficulty (F3,39 = 63.27, P < 0.001).
A significant correlation was observed with IQ for this average effect of difficulty (r = −0.61, P = 0.02).
We evaluated the effect of difficulty initiating sleep, difficulty maintaining sleep, and sleep duration on the risk of developing diabetes in separate age-adjusted and multivariable-adjusted models.
Finally, for both tasks we found an effect of difficulty on drift rates, with larger drift rates for trials with higher coherence.
A Sobel test to examine the indirect effect of difficulty accessing syringes on the relationship between injecting MA and syringe sharing confirmed the significance of the mediation pathway (P = 0.040).
Simple effects analysis revealed that this was due to a significant increase in the number of attempts required to complete the harder problems in subjects under negative [main effect of difficulty: n = 12, F 5,24) = 3.62, p =.014] or positive mood [ n = 11, F 5,24) = 3.68, p =.013] but not neutral mood [ n = 10, F 5,24) = 1.71, p =.17].
This behavioral versus neural (amygdalar) divergence regarding the effect of difficulty in CDTD tasks is probably due to the fact that behavior is the final single output of diverse neural discrete processes that may not always converge and that, case by case, may not always correlate with behavior.
