When a person tries to remember materials such as words, repeated items are remembered better if they are separated by other items, rather than being presented together. This spacing effect seems to occur in several ways, but in some circumstances it appears to reflect the influence that the perception of the first presentation has on perception of the second presentation, referred to as priming. In previous ESRC-funded research we established that when unfamiliar materials are used, changing the physical form of the item (eg by changing typefont) reduces the spacing effect, and also reduces priming. This suggests that with these materials, priming and the spacing effect are both tightly tied to the physical form of the stimulus. However, with meaningful materials such as words, changing the physical form has little effect. The reason for this is probably that familiar items are remembered in terms of their meaning, not their physical form. We can test this by investigating the influence of the meaning of one item on another, what is known as semantic priming. If this manipulation influences the spacing effect for familiar materials, it will show that parallel mechanisms operate when the spacing effect is observed with familiar and unfamiliar materials.

Human experimental response time and accuracy data