Abstract
A warning signal preceding an imperative stimulus by a certain foreperiod can accelerate responses (foreperiod effect). When foreperiod is varied within a block, the foreperiod effect on reaction time (RT) is modulated by both the current and the prior foreperiods. Using a non-aging foreperiod distribution in a simple-reaction task, Capizzi et al. (Cognition, 134, 39-49, 2015) found equal sequential effects for different foreperiods, which they credited to repetition priming. The multiple-trace theory of Los et al. (Frontiers in Psychology, 5, Article 1058, 2014) attributes the slope of the foreperiod-RT function to the foreperiod distribution. We conducted three experiments that examined these predicted relations. Experiment 1 tested Capizzi et al.'s prediction in a choice-reaction task and found an increasing foreperiod-RT function but a larger sequential effect at the shorter foreperiod. Experiment 2 used two distinct short foreperiods with the same foreperiod distribution and found a decreasing foreperiod-RT function. By increasing the difference between the foreperiods used in Experiment 2, Experiment 3 yielded a larger sequential effect overall. The experiments provide evidence that, with a non-aging foreperiod distribution, the variable-foreperiod paradigm yields unequal sequential-effect sizes at the different foreperiods, consistent with the multiple-trace theory but contrary to Capizzi et al.'s repetition-priming account. The foreperiod-RT functions are similar to those of the fixed-foreperiod paradigm, which is not predicted by the multiple trace theory.