a control group in which each participant is paired with a participant in another group (see matched-pairs design); the paired individuals are then exposed to precisely the same experiences except for the specific treatment or other condition under study. This procedure is intended to make the control group as similar as possible to the experimental group. For example, in a study of the effectiveness of rewards on children’s learning, matched individuals in the control and experimental groups would complete the same tasks under the same conditions but only those in the experimental group would be praised for good performance.