Think slow, then fast: Does repeated deliberation boost correct intuitive responding?

Influential studies on human thinking with the popular two-response paradigm typically ask participants to continuously alternate between intuitive ("fast") and deliberate ("slow") responding. One concern is that repeated deliberation in these studies will artificially boost the intuitive, "fast" reasoning performance. A recent alternative two-block paradigm therefore advised to present all fast trials in one block before the slow trials were presented. Here, we tested directly whether allowing people to repeatedly deliberate will boost their intuitive reasoning performance by manipulating the order of the fast and slow blocks. In each block, participants solved variants of the bat-and-ball problem. Maximum response time in fast blocks was 4 s and 25 s in the slow blocks. One group solved the fast trials before the slow trials, a second group solved the slow trials first, and a third mixed group alternated between slow and fast trials. Results showed that the order factor did not affect accuracy on the fast trials. This indicates that repeated deliberation does not boost people's intuitive reasoning performance.