Table 1.

Effect of COMT genotype on RT (in milliseconds ± SEM) during the VAC task

COMT genotype	LOW	INT	HIGH
val/val	770.9 ± 60.5	929.3 ± 47.2	1114.8 ± 43.9
val/met	691.6 ± 35.6	839.1 ± 51.3	1016.6 ± 58.8
met/met	726.5 ± 26.0	864.1 ± 23.8	1074.3 ± 42.8

Although there was a significant main effect of increasing level of attentional control on RT, there was no significant effect of COMT genotype or a significant interaction between demand of attentional control and COMT genotype on RT. For details, see Results.