Walter Mischel has done some very influential experiments showing that self-control at age 4 is insanely predictive of success later in life. SAT scores, income, addiction, PFC activity decades later...
They put a 4 year old child in front of a marshmallow, and ask him/her to not eat the marshmallow while they leave the room - if they abstain they get 2 when the experimenter comes back. Then they time how long it takes the kid to give up and eat it.
I'm not saying this is fraud. I'm just saying, that's a really fucking powerful test. Does that level of prediction even make sense? Can you decide that much about someone at age 4 in 15 minutes? Not just 15 minutes, but with a single scalar variable measured in those 15 minutes??
I dunno, it kinda feels too good to be true.
Maybe it measures something else, like parental income, which is insanely predictive of lifetime success. Or maybe there's something fishy going on with the study, which AFAIK has not been replicated (at least the longitudinal part).