A comparative developmental study of impulsivity in rats and humans: the role of reward sensitivity

The present study was conducted to test the hypothesis that differences in reward sensitivity between adolescents and adults account for differences in impulsivity. In a comparative study, we examined preferences for various concentrations of sucrose solutions as an operational measure of reward sensitivity in adolescent and adult rats and humans. Humans also completed self-report measures of impulsivity and reward sensitivity. There was some indication that adolescents preferred sweeter solutions compared to adults. Also, adolescents scored substantially higher on impulsivity. However, adolescents and adults did not differ in self-ratings of reward sensitivity and personality scores were not consistently related to sucrose preferences. The data highlight some of the benefits and issues that arise with developing comparative measures in humans and animals. Future comparative research using alternative behavioral paradigms is necessary to determine if and how changes in reward sensitivity influence developmental shifts in impulsivity.