Jacob "Jack" Block (April 28, 1924 – January 13, 2010)[1] was a psychology professor at UC Berkeley.
Unlike most longitudinal studies, the Blocks' focused on the psychological makeup and history of the subjects, rather than quantitative measures such as IQ.
The study tracked how the subjects' background influenced their later choices and the outcomes of their lives.
Published in The Journal of Research in Personality in 2006, it found that subjects who at 3 years old had seemed thin-skinned, rigid, inhibited and vulnerable tended at 23 to be political conservatives.
On the other hand, 3-year-olds characterized as self-reliant, energetic, somewhat dominating and resilient were inclined to become liberals.