Which trial-based method involves presenting one stimulus at a time?

The trial-based method that involves presenting one stimulus at a time is known as the Single Stimulus method. This approach is commonly used in preference assessments to determine an individual's preferences for various stimuli, particularly in applied behavior analysis.

In the Single Stimulus method, each item is presented individually to the individual being assessed, and their reactions or interactions with the item are observed. This allows practitioners to see which items capture the person's interest or engagement without the possibility of confusion from multiple items being presented at once. It is a straightforward and effective way to assess preferences, especially for individuals who may have difficulty choosing between multiple items or who may become overwhelmed by too many options.

This method contrasts with other trial-based methods where multiple stimuli are presented simultaneously or in pairs, which can complicate the assessment process and sometimes lead to unclear results regarding preference. The simplicity of the Single Stimulus method makes it particularly valuable in settings with individuals who have varying levels of cognitive and communication abilities.