Final answer:
Preference assessments are typically conducted using trial-based methods and single stimulus.
Step-by-step explanation:
Preference assessments are typically conducted using trial-based methods and single stimulus. In trial-based methods, multiple stimuli are presented and the individual's preference is determined by the number of times they choose each stimulus. In single stimulus methods, one stimulus is presented at a time and the individual's preference is determined by their response to each stimulus.