Does testing enhance mediation in paired-associate learning?

The testing effect (TE) is the finding that testing on previously studied material leads to better long-term retention as compared to restudying that material. Pyc and Rawson (2010) proposed the Mediator Effectiveness Hypothesis (MEH) as an explanation for the TE in paired-associate learning. The MEH states that review testing on cue-target word pairs strengthens semantic/associative mediators, which help participants recall targets to their cues on a later test. Pyc and Rawson found support for the MEH with Swahili-English word pairs and explicit mediation instructions, using the most rigorous means of assessing the MEH (i.e. asking participants to recall both the mediator and target to each cue). Using these procedures with spontaneous mediation conditions and unrelated English word pairs, the results of Experiments 1 and 2 failed to support the MEH. When semantic/associative or phonological mediation was explicitly encouraged in Experiment 3, the MEH was supported only for phonological mediation.