The scientists were able to raise the unsuspecting subject's self esteem in about thirty seconds.

The subjects first filled out a standardized test to establish their implicit (unconscious) self esteem level.

They were then divided into a test group, who were asked to look at the screen and do some tasks while unbeknownst to them, they were actually exposed to subliminal primes, and a second, control group, that received the same tasks only without subliminal messages.

After the exposure to the primes, both groups were asked to do certain tasks that were intentionally designed to be very hard and frustrating.

The test group turned out to be much more resistant to failure, was more persistent and spent a lot more time on the tasks at hand than the control group that gave up much faster.

Furthermore, both groups were asked to take the standardized self esteem test again after the exposure and the test group was found to have significantly higher self esteem after exposure than the control group that saw no change in self esteem before and after the experiment.

I took all the details of this work and many others like it and distilled them in the video below.