Pharmaceutical enhancement of complex problem-solving in healthy adults

A) Aims and Objectives This project aims to investigate the role of the neurotransmitter dopamine in complex decision making, and how three prescription stimulant medications that modulate dopamine levels in the brain in slightly different ways can affect the quality of complex decision making. These medications (dextroamphetamine, methylphenidate and modafinil) are increasingly used by healthy people for non-medical, cognitive enhancement purposes, however their effects on basic cognition are often found to be inconsistent, and their effects on more naturalistic, complex optimisation behaviours are not known. B) Key Question(s) Do stimulant medications, that increase dopamine in the brain, enhance, or have a deleterious effect, on the completion of a complex decision making task. More specifically do they; * Affect the amount of time taken to solve a problem? * Increase or decrease the likelihood that a participant will find the correct solution to the problem (the computational performance)? * Increase or decrease the computational distance between the participant’s solution and the correct solution (the economic performance)? * Affect the variety of search paths that participants take through the space of possible solutions? C) Research Design This study will utilize a double-blinded placebo-controlled crossover design. We will recruit 32 healthy participants with no history of neurological, psychiatric or heart conditions. Each one will participate in an initial assessment session and four testing sessions, each at least one week apart to allow for pharmaceutical washout. At each session, the participant will receive either a single dose of the three pharmaceuticals or the placebo. After a 90-minute waiting period, during which the participant fills out number of demographic and personality surveys, the participant will complete a series of computerised complex optimisation tasks and basic cognition tasks. Data collected includes the sequence and timing of the selection of items for each task solution, key variables from the more basic cognitive tasks and the answers to the survey questions.