Examining the neural mechanism behind testing effect with concrete and abstract words.

The testing effect refers to the fact that testing enhances delayed memory more than restudying does. Previous studies revealed that the testing effect can be influenced by the delay period, the type of testing, and other factors. However, a few studies have focused on how the testing effect interacts with the properties of words, such as the concreteness effect. In an event-related potential study, we investigated how concreteness affects the testing effect. The behavioral results showed that concrete words benefited more from retrieval practice than the abstract words. The event-related potential amplitude of concrete words was significantly different between retrieval practice and restudying. Source analyses showed that only concrete words elicited activity in superior parietal lobule after being retrieved. We suggest that this difference is owing to the additional imaging during the encoding and retrieving of concrete words.