If I wanted to study psychology from a perspective of attending to ONLY observable behavior, which school of thought would I subscribe to?

Behaviorism

Explanation:

Behaviorism - it is referred to the learning process theory that states that the ideas an individual acquires are based on interaction with the surrounding.

The main focus of this study is to regularized scientific study. it works on the principle of shaping behavior through positive or negative reinforcement.

There are broadly two types of behaviorism. methodological and radical.