The interactive effect of external rewards and self-determined choice on memory

Abstract

Both external motivational incentives (e.g., monetary reward) and internal motivational incentives (e.g., self-determined choice) have been found to promote memory, but much less is known about how these two types of incentives interact with each other to affect memory. The current study (N = 108) examined how performance-dependent monetary rewards affected the role of self-determined choice in memory performance, also known as the choice effect. Using a modified and better controlled version of the choice paradigm and manipulating levels of reward, we demonstrated an interactive effect between monetary reward and self-determined choice on 1-day delayed memory performance. Specifically, the choice effect on memory decreased when we introduced the performance-dependent external rewards. These results are discussed in terms of understanding how external and internal motivators interact to impact learning and memory.

Fig. 1

Schematic depiction of the encoding phase and the recognition test. During the encoding phase, participants were asked to remove the occluder on the left or right side to remember the image underneath. In the choice condition (选择: Choice), participants made their own decision regarding which occluder to remove, whereas in the fixed condition (非选择: Fixed), participants had to remove the predetermined occluder on the side of the red arrow. In the control group, participants were informed that they would receive a fixed amount of subject payment and they received neutral feedback in the test. In the two reward groups, participants were informed that their payment would be dependent on their memory performance and they received performance-dependent rewards in the test. Specifically, in the ambiguous reward group, participants were informed orally, during the encoding phase, of the average reward amount for the experiment (without specific information about the exact amount for each correct response), whereas in the explicit reward group, participants were informed visually of the exact reward amount during each trial

Fig. 2

Mean memory performance (corrected accuracies) for the choice and fixed conditions when participants received the fixed payment (the control group) or when they received performance-dependent rewards (the ambiguous reward group and the explicit reward group). Error bars represent the standard error of the mean across participants. *p < 0.05, ***p < 0.001, ns non-significant