"he was an old, dazed, disordered-looking fellow, a behavioralist"

 Behaviourism is school of psychology positing that all types of activity - thought, acting, feeling - can be called 'behaviours' and studied in a scientific, objective way that excludes hypothetical ideas such as 'the mind', or any abstract theories. Psychologists associated with Behaviourism include Ivan Pavlov, Edward Lee Thorndike, John B. Watson and  B. F. Skinner.