Adding a healthy side to a hamburger decreases its perceived calories total

Not a widely known research but a very interesting one from Alexandre Chernev1:

The results in brief

Subjects were asked to guess the number of calories in “not so healthy” meals, like hamburgers. Others were asked to guess the number of calories in the same meals but where a “healthy” side was added, like celery sticks. Of course, adding anything to the same meal only adds to its calories total, but subjects being shown the meals with the added healthy sides guessed they were worth less calories than the same meals without the healthy side.

The mere presence of the healthy sides acted as if it would somehow decrease the unhealthy impact of the whole meal. This illustrates how judgement and perception are impacted by the whole combination of items being judged and not by each individual element.

How could it be used in other contexts

This same effect could certainly be used in cases where you want to diminish the perceived negative aspects of an element by adding another one which gives the impression to negate it by being positive, even though the two experiences may not be on the same dimension.

This is also linked to the human tendency known as the moral or self licensing effect.

  1.  Chernev, Alexander. 2011. The Dieters Paradox. Journal of Consumer Psychology. 21(2): 178-183. (link)