Mediators can be created in both massed and spaced practices. However, mediators formed during massed practices are easily forgotten by the time of the actual test. Mediators formed during spaced practices tend to be longer lasting, which partly explains the spacing effect.

Mediator Hypothesis

A memory strategy where one associates multiple items with each other by using imagery, sentence generation, or other strategies (e.g. dog and spoon).

California Polytechnic State University, San Luis Obispo

Long-term recall is improved when studying is broken up into many short sessions rather than long concentrated ones (memory consolidation is improved). 

Spacing effect

Morehead, K., Dunlosky, J., Rawson, K. A., Bishop, M., & Pyc, M. A. (2018). Does mediator use contribute to the spacing effect for cued recall? Critical tests of the mediator hypothesis. Memory (Hove), 26(4), 535–546. https://doi.org/10.1080/09658211.2017.1381266

Morehead et al. (2018) Does mediator use contribute to the spacing effect for cued recall? Critical tests of the mediator hypothesis.

The spacing effect has been shown to improve long-term recall in a variety of domains such as: 
- Conditioning (even in non-human animals)
- Verbal learning
- Motor learning
- Learning educational material

Scope of the spacing effect (different domains)

Spacing has shown to improve long-term recall more than massing by many studies. Some people however (such as E.Z. Rothkopf during in September of 1977), have posited that massing is better mode of studying when dealing with problems of induction. Kornell, N., & Bjork (2008) presented compelling evidence against this claim (spacing is also better for induction).

Effects of Spacing compared to Massing

The two main variables influencing the spacing effect are the spacing interval (lag) and the retention interval (test delay).

Spacing effect variables

Mediators

Distributed practice is an effective study strategy that involves spacing out learning sessions over time in short durations, rather than cramming all at once. This method provides the necessary time for memory consolidation to occur. Conversely, massed practice or cramming can over-activate links between concepts, causing a learner to get stuck and preventing access to other learned information.

Distributed Practice

Academic literature and references studying the spacing effect can be categorized into topics such as its early origins, displays of the effect across different learning domains, and comparisons between the effects of spacing versus massing.

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