As in Lesch (2008), comprehension was assessed using a semantic relatedness task with paired-response contingent scoring. Three types of knowledge were tested for each symbol: its verbal label, prohibited or required actions, and consequences of failures to comply. On each trial, participants viewed a symbol paired with a label and were asked whether or not the label matched that aspect of the meaning of the symbol. Time taken to respond was recorded and participants also rated their confidence in their decisions. During each testing session, participants also rated perceived hazard, intent to comply, as well as their level of agreement with statements regarding perceived control. In order to examine the duration of any training benefit, participants were tested immediately following training and again 2 weeks later