"Starting in the early 1950s I asked every famous or important person I photographed to jump for me. I was motivated by a genuine curiosity. After all, life has taught us to control and disguise our facial expressions, but it has not taught us to control our jumps. I wanted to see famous people reveal in a jump their ambition or their lack of it, their self-importance or their insecurity, and many other traits." –P.H.
(http://philippehalsman.com/?image=jumps)
Halsman commented, "When you ask a person to jump, his attention is mostly directed toward the act of jumping and the mask falls so that the real person appears." The photographer developed a philosophy of jump photography, which he called jumpology. He published Philippe Halsman's Jump Book in 1959, which contained a tongue-in-cheek discussion of jumpology and 178 photographs of celebrity jumpers.
(https://en.wikipedia.org/wiki/Philippe_Halsman)