In his own work, DeWall has seen students who meet for as little as 15 minutes feel hurt when they are suddenly excluded from a group.
So for the contestants on the reality show, for whom the experience lasts for many weeks, the psychological impact of rejection may be even more profound.
"Six weeks of getting to know someone and then getting excluded, I would say that would have lots of serious consequences," said DeWall.
And while some might question whether one man could impact the emotions of so many women, studies have shown it to be entirely plausible.
Kip Williams, a professor of psychological sciences at Purdue University, noted that in his own studies, people will display emotional pain in a variety of settings. Some people have been offended when a computer excludes them, and African-American students have been offended when other students -- whom they are led to believe are members of the Ku Klux Klan -- won't pass them the basketball during a game.
"We don't mind saying 'no' to them, but we don't want to be said 'no' to by anybody," said Williams.
Compound this exclusion with the participants' obligation to remain mum about it, and it may be a formula for disaster. In the lab, DeWall said, researchers have found that suppressing emotion for even as little as 15 minutes is related to all sorts of negative consequences -- both emotional and physical.
He doesn't know the effect of emotional suppression for several weeks, which the women on "The Bachelor" were contractually obligated to endure.
"I don't think actually that my university would let me do that, for a variety of different reasons," said DeWall.
Williams agrees that reality TV sometimes gets away with questionable activities.
"Most of these TV shows, we could never do in an experiment in a university. None of them would get approval," said Williams.
Both of the finalists had to endure some period of suppression -- Malaney between her initial rejection and the first taping for the finale in January (where she reconciled with Mesnick, but still had to keep quiet), and Rycroft between the January taping and the airing of the episode on Monday.
Williams speculated that given the difficulty in bottling up emotions, some contestants might swear a friend to secrecy to help themselves but avoid legal troubles.
Even the person doing the rejecting -- in this case, Mesnick -- might be hurting himself emotionally. While most data are on people being excluded, DeWall noted that some people who are rejectors show less of a desire to connect with other people.
Mesnick's previous experience on the show may have played a role as well. Mesnick was among the final two suitors for DeAnna Pappas on a prior season of "The Bachelor," But she rejected him in the finale. Having been rejected previously may have made Mesnick, who is also divorced, less sensitive to rejecting someone else, as exposure to painful events may make someone react less to negative ones in the future.
"He [Mesnick] wasn't that concerned with another person's pain," DeWall noted.
"If I were making a show like this, I think it would be very important to keep this in mind, because it does pose such a threat to well-being -- you're really hurting people."