Conditioned stimuli and the expression of extraversion: Help or hindrance?

Upon consideration of the unconditioned and particularly the conditioned st imuli that have been proposed to participate in the generation of incentive motivational states and, by extension, of extraversion, the nature of the contribution of NAS DA becomes less clear. Different kinds of conditioned s timuli can also exert strong control over the expression of behavioral sens itization. How might such stimuli affect the ability of experience-dependen t processes to introduce stable individual differences in the development a nd expression of extraversion trait levels?