Looks like he went to Harvard during the time that BF Skinner was the bulwark of the Psychology Dept there. Leary did not conform to Skinner’s insistence that we study the observable external behaviors and relevant contingencies, in organisms, including humans. Leary wanted to explore the internal, 'the mind". He apparently started out doing what looked, originally, like some bona fide research, while he was at Harvard, but then started transitioning to a more party-ish, rather than scientifically studious, lifestyle. I guess he went downhill from there.
Oh, I did meet B.F. Skinner.