The Effect of Retrieval Practice on Transitive Inference.

Compared to restudying, retrieval practice has often been found to enhance memory (the testing effect). However, it has been proposed that materials with high element interactivity may not benefit from retrieval practice. Transitive inference (TI) requires just such interactivity, in which information must be combined across multiple learning elements or premises. The current study employed a 7-element TI paradigm in which participants initially learned a set of premises (e.g., A > B, B > C, C > D, etc.), then engaged in either restudy or retrieval practice with the premises, and then were given a final test that assessed memory for the original premises and one's ability to make transitive inferences about them (e.g., to infer that B > D). Three experiments examined TI on final tests with retention intervals of a few minutes (Experiment 1), 2 days (Experiment 2), or up to a week (Experiment 3). Retrieval practice consistently failed to enhance transitive inference. Furthermore, retrieval practice significantly reduced TI in Experiment 1. Across experiments, TI was numerically worse in the retrieval-practice than restudy condition in 4 of 5 comparisons, and a small-scale meta-analysis revealed a significant negative effect of retrieval practice on TI.

The effect of age on relational encoding as revealed by hippocampal functional connectivity.

The neural processes mediating cognition occur in networks distributed throughout the brain. The encoding and retrieval of relational memories, memories for multiple items or multifeatural events, is supported by a network of brain regions, particularly the hippocampus. The hippocampal coupling hypothesis suggests that the hippocampus is functionally connected with the default mode network (DMN) during retrieval, but during encoding, decouples from the DMN. Based on prior research suggesting that older adults are less able to modulate between brain network states, we tested the hypothesis that older adults' hippocampus would show functional connectivity with the DMN during relational encoding. The results suggest that, while the hippocampus is functionally connected to some regions of the DMN during relational encoding in both younger and older adults, older adults show additional DMN connectivity. Such age-related changes in network modulation appear not to be mediated by compensatory processes, but rather to reflect a form of neural inefficiency, most likely due to reduced inhibition.