The time course of breaking mental sets and forming novel associations in insight-like problem solving: an ERP investigation.

In the present study, high-density event-related potentials were recorded to examine the electrophysiological correlates of logogriph problem solving in using a new experimental paradigm (learning-testing model) that was adopted in order to enable subjects to find a solution on their own initiative. For each trial, subjects were given a target logogriph followed by three types of base logogriphs: surface similarity logogriphs (SUSL, the base logogriph and target logogriph share some same words), structural similarity logogriphs (STSL, the base and target logogriphs do not have any words in common), and baseline logogriphs (BSL, the base and target logogriphs are all simple character-generation tasks). The results demonstrated a more negative event-related potential deflection during STSL than during SUSL in both the 300-500 and 1,100-1,300 ms time windows, most likely reflecting the breaking of mental sets during insight-like problem solving. Moreover, SUSL and STSL demonstrated greater positivity than BSL in a time window between 900 and 1,700 ms, possibly reflecting processes such as forming novel associations.