Does extraversion predict positive incentive motivation?

I focus on a number of issues arising from Depue and Collins's target article that require further consideration: (1) data that fail to confirm extraversion effects in positive incentive experiments; (2) the role of personality factors, other than extraversion, in dopamine agonism on positive mood states; (3) the role of extraversion in nonspecific arousal, indicating that extraversion may not be an homogeneous trait; and (4) the problem of identifying neurobiologically important traits from existing structural models of personality. I applaud the heuristic value of the model presented and suggest ways in which aspects of the model may be used to identify the personality traits associated with positive incentive motivation.