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

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.

The effect of choice on intentional and incidental memory.

Recent studies have revealed that memory performance is better when participants have the opportunity to make a choice regarding the experimental task (choice condition) than when they do not have such a choice (fixed condition). These studies, however, used intentional memory tasks, leaving open the question whether the choice effect also applies to incidental memory. In the current study, we first repeated the choice effect on the 24-h delayed intentional memory performance (experiment 1). Next, using an incidental paradigm in which participants were asked to judge the category of the items instead of intentionally memorizing them, we observed the choice effect on judgment during encoding and memory performance in a 24-h delayed surprise test (experiment 2). Participants judged more accurately and quickly and had better recognition memory for items in the choice condition than for items in the fixed condition. These results are discussed in terms of the role of choice in both intentional and incidental memory.

Reward-driven attention alters perceived salience.

Many studies have revealed that reward-associated features capture attention. Neurophysiological evidence further suggests that this reward-driven attention effect modulates visual processes by enhancing low-level visual salience. However, no behavioral study to date has directly examined whether reward-driven attention changes how people see. Combining the two-phase paradigm with a psychophysical method, the current study found that compared with nonsalient cues associated with lower reward, the nonsalient cues associated with higher reward captured more attention, and increased the perceived contrast of the subsequent stimuli. This is the first direct behavioral evidence of the effect of reward-driven attention on low-level visual perception.

The influence of rewards on incidental memory: more does not mean better.

Studies have revealed that rewards promote long-term memory, even in an incidental way. However, most previous studies using the incidental paradigm have included two reward levels, and it is still not clear how the reward magnitude influences memory. Adopting the incidental paradigm and three reward levels, the current study revealed that the reward magnitude impacted 1-d delayed episodic memory in a nonlinear, inverted U-shaped pattern. An additional experiment showed that there was no reward effect in immediate episodic memory. Our results support the dopaminergic memory consolidation theory and further imply that the reward magnitude needs to be considered in the theory.

The Bright and Dark Sides of Performance-Dependent Monetary Rewards: Evidence From Visual Perception Tasks.

Studies have shown that performance-dependent monetary rewards facilitate visual perception. However, no study has examined whether such a positive effect is limited to the rewarded task or may be generalized to other tasks. In the current study, two groups of people were asked to perform two visual perception tasks, one being a reward-relevant task and the other being a reward-irrelevant task. For the reward-relevant task, the experimental group received performance-dependent monetary rewards, whereas the control group did not. For the reward-irrelevant task, both groups were not rewarded. The two tasks were randomly intermixed trial by trial (Experiment 1) or presented block by block (Experiment 2) or session by session (Experiments 3a, 3b, and 3c). Results showed that performance-dependent monetary rewards improved participants' performance on the relevant task in all experiments and impaired their performance on the irrelevant task in Experiments 2, 3a, 3b, and 3c. These results suggested that monetary rewards might incur a cost on reward-irrelevant tasks. Finally, the benefit of monetary rewards disappeared when they were no longer provided during the final session. This is the first study that reveals both the bright and dark sides of the performance-dependent monetary rewards in visual perception.