Does motor noise contaminate estimates of the precision of visual working memory?

The continuous-report task, in which subjects report the color of visual working memory representation by clicking on a color wheel, has become the gold standard for measuring the precision and number of representations stored in visual working memory. This task requires fine motor control, typically with a mouse, but the precision of responses have been interpreted as being entirely due to the precision of the memory representations, without regard to the contribution of noise from the response effectors (i.e., motor control of the hand). Here we tested the seemingly likely possibility that motor noise contaminates our estimates of visual memory representations in the continuous-report task by simply asking subjects to complete the color wheel continuous-report task using either their dominant or non-dominant hand on different blocks of trials. We found that subjects took longer to complete the task with their non-dominant hand, but this did not affect the precision of their responses. Our findings suggest that this commonly used task to study visual memory may be relatively immune from contamination by motor noise at the output stage.