My research investigates the neural mechanisms underlying the valuative and executive processes of decision-making. I employ complementary neuroscience methodologies. Functional magnetic resonance imaging (fMRI) specifies the neural instantiation of cognitive processes, such as dissociating between the valuative, contingency processing, and control mechanisms involved in human decision making. Manipulation techniques provide causal tests of relations between neural and cognitive processing, as when using acute tryptophan depletion (ATD) to examine the role of serotonin in decision making and valuation. Finally, individual differences in choice preferences provide information about how genetic polymorphisms and trait hormone levels may account for individual variation, through effects on dopaminergic and serotonergic transmission.