Does retrieval practice depend on semantic cues? Assessing the fuzzy trace account of the testing effect

Retrieval practice enhances long-term retention more than restudying; a phenomenon called the testing effect. The fuzzy trace explanation predicts that a testing effect will already emerge after a short interval when participants are solely provided with semantic cues in the final test. In the present study, we assessed this explanation by gradually reducing the surface features overlap between cues in the learning phase and the final recognition test. In all five experiments, participants in the control/word condition received as final test cues the same words as in the learning phase. The experimental final test cues consisted of scrambled words, words in a new context, scrambled words in a new context (Experiment 1), synonyms (Experiment 2), or images (Experiments 3, 4a, 4b). A short-term testing effect was only observed for the image final test cues. These results do not provide strong support for the fuzzy trace explanation of the testing effect.