Who studied what motivates human behavior?
Here's what I've got.
On the side of formulations concerning motivation within psychodynamic camps Freud (1932/1962) ; Hartman, (1939) which spawned an empirical amount of research that was integrated and interpreted within these paradigms.
White (1959) Seminal review of the inadequacies of both behavioral and psychodynamic drive theories that explained active exploration, curiosity, and many others associated with motivation, learning, and development, and sadly study into this field faded as a covus of inquiry.
(Will finish this later, time went by a bit too quickly)