What does a cumulative record emphasize in behavioral data?

A cumulative record is primarily designed to emphasize the frequency or rate of performance over time. It visually represents the total number of responses accumulated across a specific period, allowing practitioners to track how behavior changes in relation to interventions or across different sessions. As data is collected, the graph builds upward, showcasing a clear depiction of increases or decreases in behavioral responses.

In contrast, focusing on the total duration of engagement does not inherently capture how often a behavior occurs, nor does it provide a detailed view of performance trends over time. Additionally, while the variety of stimuli used can be relevant to certain analyses, it is not the central focus of cumulative records. Lastly, looking at the maximum performance achieved does not reflect ongoing behavior changes but rather insight into peak performance without considering frequency over time. Thus, the emphasis of a cumulative record is on the frequency or rate of performance, making this the correct choice.