Helen Fisher, the renowned biological anthropologist and one of the paper's co-authors, interviewed some of the participants and said that even she found their pain distressing.

"Any kind of novelty, any activity that's new, exciting, challenging, possibly dangerous, will work," said Helen Fisher, a biological anthropologist at Rutgers University and a co-author of the study.

When Bryant did come home again, he and Fisher became co-captains, which meant Fisher's arrival bumped Lamar Odom out of that honorable designation he held the past two seasons.