The study, published in the Journal of Consumer Research, found people's willingness to take a pill or drug depends on whether the trait the drug promises to enhance is one they consider fundamental.

Study authors Jason Riis of New York University and Harvard Business School, Joseph P. Simmons of Yale University and Geoffrey P. Goodwin of Princeton University examined the moral dilemmas that arise as technologies develop that not only cure disease but also enhance already-healthy people.

As many young people without diagnosed disorders or deficits take Ritalin or Adderall to improve concentration or anti-depressants to lift their moods, this study examines what makes healthy people willing to take pills.

The researchers determined people do not feel comfortable using a pill to enhance a trait they believe to be fundamental to their identity. But less-fundamental traits, including concentration, are more acceptable targets.