Development of Monetary and Social Reward Processes

Abstract

The current study investigated monetary and social reward processing in children, adolescents and adults with adapted incentive-delay tasks and self-report questionnaires. Both tasks had three levels of reward magnitudes (no, low, and high). Qualified participants received 15 Chinese Yuan and an honor certificate as monetary and social rewards, respectively. The results indicated that both monetary and social rewards effectively speeded up responses for all three age groups as reward magnitude increased in the choice reaction time task. Among adolescents and adults, males exhibited faster responses in high reward than in low reward condition, while females responded equally fast in both conditions. Among children, girls responded faster to high reward than low reward condition. However, boys committed more errors than girls in low and high reward conditions, and they had exhibited more errors in high reward than that in no reward condition for social reward. Regarding the subjective ratings, both children and adolescents reported higher motivation for social reward than for monetary reward. These findings indicated that the males in the adolescent and adult groups were more sensitive to reward than were the females. Moreover, tangible and quantitative social reward had stronger incentive power than monetary reward among children and adolescents.

Figure 1

Mean reaction times (ms) as a function of age group, participant gender and reward magnitude in the formal experiment.

Figure 2

(a) Mean error rates as a function of reward magnitude and participant gender for the children’s group. (b) Mean error rates as a function of reward magnitude for boys in the children’s group on the SID task.

Figure 3

Subjective rating scores as a function of age group and reward type.

Figure 4

Examples of the trial sequence in the MID and SID tasks. Participants were asked to discriminate the shape of the target figure (triangle or square). During the reward anticipation period, a hollow circle or a circle with one or two horizontal lines signaled the magnitude of the potential reward in the current trial. Based on the task, the reward magnitude of the current trial and the participant’s response, Chinese coins or smiling faces were presented as monetary or social reward feedback stimuli.