A major shortcoming of existing computational models is that they do not account for motivational and individual differences. Errors are motivationally salient events that prompt psychophysiological changes that include skin conductance and heart rate deceleration (Hajcak et al., 2003b; Hajcak, McDonald, & Simons, 2004). Although these peripheral responses are consistent with both a defensive and orienting response, a recent study from our lab found that the defensive startle reflex was larger following errors than correct responses (Hajcak & Foti, 2008). In fact, Hajcak and Foti found that the ERN predicted degree to which the startle reflex was potentiated after errors. Collectively, these data suggest that the ERN might reflect error-detection that is utilized for motivational ends. Thus, amplitude of the ERN might relate to the significance of an error. This possibility was first suggested by Gehring and colleagues (1993) who reported that the amplitude of the ERN was larger when an error was made when participants were told to be more accurate, whereas the ERN was smaller when participants were told to respond faster. Therefore, by emphasizing accuracy, the authors
