Developmental changes in individual alpha frequency: Recording EEG data during public engagement events.

Statistical power in cognitive neuroimaging experiments is often very low. Low sample size can reduce the likelihood of detecting real effects (false negatives) and increase the risk of detecting non-existing effects by chance (false positives). Here, we document our experience of leveraging a relatively unexplored method of collecting a large sample size for simple electroencephalography (EEG) studies: by recording EEG in the community during public engagement and outreach events. We collected data from 346 participants (189 females, age range 6-76 years) over 6 days, totalling 29 hours, at local science festivals. Alpha activity (6-15 Hz) was filtered from 30 seconds of signal, recorded from a single electrode placed between the occipital midline (Oz) and inion (Iz) while the participants rested with their eyes closed. A total of 289 good-quality datasets were obtained. Using this community-based approach, we were able to replicate controlled, lab-based findings: individual alpha frequency (IAF) increased during childhood, reaching a peak frequency of 10.28 Hz at 28.1 years old, and slowed again in middle and older age. Total alpha power decreased linearly, but the aperiodic-adjusted alpha power did not change over the lifespan. Aperiodic slopes and intercepts were highest in the youngest participants. There were no associations between these EEG indexes and self-reported fatigue, measured by the Multidimensional Fatigue Inventory. Finally, we present a set of important considerations for researchers who wish to collect EEG data within public engagement and outreach environments.

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.