Which effect describes better long-term retention achieved through distributed study versus massed study?

The spacing effect describes the phenomenon where information is retained more effectively when learning sessions are spaced out over time, rather than when they are crammed or massed into a short period. This approach allows for better long-term retention because it gives the brain time to consolidate and reinforce the information learned. When studying is distributed, learners have the opportunity to revisit material at intervals, which aids in transferring knowledge from short-term to long-term memory.

In contrast, the other effects mentioned have different implications for memory. The testing effect emphasizes how retrieval practice enhances memory retention, while the recency effect focuses on the tendency to better recall items that were presented most recently. The primacy effect refers to improved recall for items presented at the beginning of a list. However, none of these directly address the benefits of distributed practice over massed practice, which is specifically captured by the spacing effect.