Appearance is functional for pills, study confirms

From the NYT:

New research suggests that changing the color of a person’s pills — by switching to a generic from a brand name drug, for example — sharply reduces the chances that the patient will continue to take it.
....
Compared with patients whose pills remained the same, those whose pills’ color was changed were 53 percent more likely to stop buying them. A change in shape also affected the patients’ use of medication, but that was not statistically significant.
“I think we’ve identified another hurdle to medication adherence and a relatively easy way to fix it,” said the study’s lead author, Dr. Aaron S. Kesselheim of Brigham and Women’s Hospital in Boston. “Require that brand names and generics should look alike. The color of a pill does have clinical relevance.”

The most striking thing to me is the apparent intertwining of reason and emotion: patients apparently don't like having their pills changed.  Color is functional not as a pure informational signal (as if there were any such thing) but as a familiar, accepted feature--like a heart-shaped gift box or matching green farm equipment.  As Mark McKenna has argued, "utilitarian" functionality and "aesthetic" functionality are intertwined, and the aesthetic is often more important than the merely utilitarian.

Another point is that the effect is small but significant--the discontinuance rate was individually low even for changed color, but given that refills are regularly needed and given the serious effects of discontinuing the medication, the harm is still potentially substantial.  So for how many people need a feature be functional in order to count, legally speaking?