In a Paired Stimulus assessment, how many items are presented at one time?

In a Paired Stimulus assessment, two items are presented at one time to determine preference between them. This method involves showing an individual two stimuli simultaneously and allowing them to choose one. The selections made over multiple trials help identify which items the individual prefers based on their choices.

Using two items allows for a clear comparison, making it straightforward to observe preferences without the potential confusion that might arise from presenting more items at once. Presenting one item would not facilitate a comparison, and presenting three or four would complicate the decision-making process, making it challenging to interpret which stimulus was preferred. Thus, the correct answer reflects the fundamental design of the assessment, which is focused on direct comparisons between two distinct options.