Abstract
Visual stimuli in the current trial tend to be reproduced more closely to the previous trial, an effect termed serial dependence (SD). Most studies show SD for stimuli when only one of its features is task-relevant. However, in interceptive actions, speed, time to contact, and path length are inherently correlated and could each influence performance in the subsequent trial. We investigated which of these features caused SD using three conditions. Participants (n = 24) performed an online task where they had to press a button while a red square target moving at a constant speed hit a vertical barrier. Blocks could have a single constant distance, speed, or time, with the other two features varying in five levels. We measured the temporal error as the difference between times of interception and response. Each participant's temporal errors were fed into multiple linear regressions with current and previous trial distance, speed, or time as regressors, depending on the condition. The previous trial coefficient was significantly different from zero in a one-sample two-tailed t-test in all conditions, suggesting that none of these features are solely responsible for the bias. Then, we fitted a second model to the previous trial coefficients, using the variables that varied or remained constant as regressors in each block. We found that only the speed and time terms were significantly different from zero in a one-sample two-tailed t-test, indicating that speed and time variations contribute towards SD, whereas the distance does not, even when it is informative. Further experiments are needed to determine whether speed and time are directly stored between trials or both influence a third unstudied variable that could cause SD.