Outcomes of the Experiment
Lachner and colleagues (1) created an experiment (Experiment 2) in which they tested these different hypotheses against each other. They had students study two related texts and asked them to either a) explain the main ideas to a fictitious person or b) write down everything they remember (written retrieval practice). In addition, they had students engage with either of these activities between reading the two texts or after reading both texts (in-between versus after-study conditions).
They found that students performed best in the ‘in-between explaining’ condition, followed by the ‘in-between retrieval practice’ condition, followed by the ‘after-study explaining’ condition, and followed by the ‘after-study retrieval practice’ condition. Thus, engaging in any of the two study activities between two texts proved to be very beneficial. Furthermore, explaining outperformed retrieval practice, which indicates that explaining, indeed, seems to engage different, and conducive processes for knowledge build-up and maintenance compared to retrieval practice alone.
Interestingly, the authors conducted another experiment (Experiment 1) in which they had students do oral retrieval of the main ideas. In that experiment, they did not find a difference between explaining and retrieval practice. Thus, there seems to be something about ‘thinking aloud’ that triggers organizational processes for knowledge acquisition. Retrieval practice in itself – as we have seen in the first experiment presented here – is not the decisive driving factor, but something about ‘social presence’ and the associated deeper organization of knowledge that takes place when we explain ideas to someone else seems to hold the key of the effects revealed in their study.
