What is emphasized in a good field sobriety test regarding cognitive load?

A good field sobriety test emphasizes the division of the subject's attention because the purpose of these tests is to assess a person's cognitive and physical abilities simultaneously. Dividing the subject's attention is crucial as it mimics real-life driving situations where a driver must perform multiple tasks at once—such as steering, observing traffic, and responding to events on the road. This aspect helps to reveal impairments caused by alcohol or drugs that might not be apparent through simple physical tasks alone.

By requiring the individual to focus on more than one task, the test aims to determine if their ability to multi-task is compromised. This cognitive load assessment provides a clearer indication of whether the subject's mental faculties are sufficiently impaired to affect safe driving, which is the ultimate goal of the field sobriety test.