Depue & Collins's general idea of a functional relationship between DA acti
vity and extraversion is an important step toward an integrative biological
model of personality. However, focusing primarily on incentive motivation
and variations in VTA DA activity as basic behavioral and biological compon
ents underlying extraversion appears too limited. Existing data suggest tha
t responsivity to changes in DA activity is higher in introverts than in ex
traverts. This may reflect a general, extraversion-related characteristic o
f the entire dopaminergic network in the brain.