We used a delayed-estimation paradigm to characterize the joint effects of set size (one, two, four, or six) and delay duration (1, 2, 3, or 6 s) on visual working memory for orientation. We conducted two experiments: one with delay durations blocked, another with delay durations interleaved. As dependent variables, we examined four model-free metrics of dispersion as well as precision estimates in four simple models. We tested for effects of delay time using analyses of variance, linear regressions, and nested model comparisons. We found significant effects of set size and delay duration on both model-free and model-based measures of dispersion. However, the effect of delay duration was much weaker than that of set size, dependent on the analysis method, and apparent in only a minority of subjects. The highest forgetting slope found in either experiment at any set size was a modest 1.14°/s. As secondary results, we found a low rate of nontarget reports, and significant estimation biases towards oblique orientations (but no dependence of their magnitude on either set size or delay duration). Relative stability of working memory even at higher set sizes is consistent with earlier results for motion direction and spatial frequency. We compare with a recent study that performed a very similar experiment.

ABTRACT 12 Previous work has shown that humans distribute their visual working memory (VWM) 13 resources flexibly across items: the higher the importance of an item, the better it is 14 remembered. A related, but much less studied question is whether people also have control 15 over the total amount of VWM resource allocated to a task. Here, we address this question by 16 testing whether increasing monetary incentives results in better overall VWM performance. In 17 two experiments, a total of 380 subjects performed a delayed-estimation task on the Amazon 18 Turk platform. The base payment was $1 in Experiment 1 and $5 in Experiment 2. 19Additionally, subjects received a bonus payment based on their performance. The maximum 20 bonus that a subject could receive differed between groups and ranged from $0 to $10 in 21 Experiment 1 and from $0.50 to $4 in Experiment 2. On average, performance was better in 22 Experiment 2 than in Experiment 1, but we found no effect of the amount of bonus on VWM 23 performance in either experiment. These findings provide further evidence for flexibility in 24

Previous work has shown that humans distribute their visual working memory (VWM) resources flexibly across items: the higher the importance of an item, the better it is remembered. A related, but much less studied question is whether people also have control over the total amount of VWM resource allocated to a task. Here, we approach this question by testing whether increasing monetary incentives results in better overall VWM performance. In three experiments, subjects performed a delayed-estimation task on the Amazon Turk platform. In the first two experiments, four groups of subjects received a bonus payment based on their performance, with the maximum bonus ranging from $0 to $10 between groups. We found no effect of the amount of bonus on intrinsic motivation or on VWM performance in either experiment. In the third experiment, reward was manipulated on a trial-by-trial basis using a within-subjects design. Again, no evidence was found that VWM performance depended on the magnitude of potential reward. These results suggest that encoding quality in visual working memory is insensitive to monetary reward, which has implications for resource-rational theories of VWM.