What cognitive ability is particularly tested when asking a subject to count backwards during an SFST?

When a subject is asked to count backwards during a Standardized Field Sobriety Test (SFST), the primary cognitive ability being tested is concentration and attention. This task requires the individual to focus on the numbers while simultaneously inhibiting other thoughts, which challenges their mental processing and ability to pay attention to the task at hand.

Counting backwards is not a routine task for most people, which makes it more cognitively demanding, as it often requires recalling the sequence of numbers and being able to perform the operation in reverse order. This taps heavily into one's concentration levels and overall attention span. Alcohol or impairing substances can greatly affect an individual's ability to stay focused, thus making this task a reliable indicator of potential impairment.

While memory recall, numerical skills, and language proficiency could be indirectly involved in this task, they are not the primary focus of what is being assessed in the context of SFSTs. The emphasis is on how well an individual can maintain their concentration and attention while performing a relatively challenging task.