| Externalizing psychopathology represents a spectrum of commonly co-occurring psychiatric disorders related to substance use and antisocial behavior. Behavioral disinhibition is a common psychological characteristic among the various facets of externalizing psychopathology. It reflects a tendency to engage in, or failure to inhibit, substance use and antisocial behavior despite repeated experience with negative physiological, psychological, and social consequences. Although theory and evidence suggests behavioral disinhibition represents a key etiologic factor in the development and persistence of externalizing psychopathology, little is known about the information processing systems and mechanisms underlying this psychological diathesis. The current research addressed this issue by investigating a quantitative model of working memory and approach-avoidance decision-making processes in a popular measure of behavioral disinhibition, the go/no-go discrimination task. Separate signal detection theory and linear ballistic accumulator models were used to operationalize performance on two cognitively distinct go/no-go tasks. A total of 510 subjects completed either a high working memory load (n=258) or a low working memory load (n=252) go/no-go task. Subjects who completed these separate go/no-go tasks did not differ in terms of gender composition, age, IQ, externalizing psychopathology, and performance on separate dual-span measures of executive working memory capacity. However, subjects did differ in terms of their go/no-go task accuracy and response time performance. Consistent with previous research, structural equations modeling path analyses found that high levels of working memory load interfered with subject's ability to make accurate and efficient approach-avoidance decisions; and, reduced working memory capacity partially accounted for the association between high levels of externalizing psychopathology and difficulty with reward-approach (i.e., go) and punishment-avoidance (i.e., no-go) signal processing. Moreover, results demonstrated that superior working memory capacity was associated with superior approach-avoidance decision making, independent of subject's history with externalizing psychopathology and whether they completed the low or high working memory load task. Together, findings suggest impaired working memory processes lead to a tendency for behavioral disinhibition in general, and in those with high levels of externalizing psychopathology in particular. Findings also suggest that high working memory capacity can mitigate the negative effects that high externalizing psychopathology and working memory load have on approach-avoidance signal processing. |
