David DeSteno in the New York Times:
Empirically speaking, does the experience of compassion toward one person measurably affect our actions and attitudes toward other people? If so, are there practical steps we can take to further cultivate this feeling? Recently, my colleagues and I conducted experiments that answered yes to both questions.
In one experiment, designed with the psychologist Paul Condon and published in the Journal of Experimental Social Psychology, we recruited people to take part in a study that was ostensibly about the relation of mathematical ability to taste perception — but that in actuality was a study of how the experience of compassion affects your behavior.
Each experimental session consisted of three individuals: a real participant and two confederates (i.e., people who secretly worked for us). First, the participants were told that they had four minutes to solve as many of 20 difficult math problems as they could and that they would receive 50 cents for each one they solved correctly. Twenty was far more than the typical person could do; the average number solved was 4. After time expired, the experimenter approached each person to ask how many problems he or she had solved, paid the person accordingly, and then had the person place his or her work in the shredder.