THE RELATIONSHIP BETWEEN THE ILLUSION OF CONTROL AND THE DESIRABILITYBIAS

Desirability bias is the tendency to overpredict desirable outcomes an d underpredict unwanted results. The illusion of control is the tenden cy to believe that, or act as if, one can skillfully influence and con trol outcomes of chance events. These two related phenomena cause peop le to paint a 'rosy picture' of current reality or the future (McKenna , 1993). The circumstances under which the two biases operate and the nature of the relationship between them have been the subject of specu lation in a few recent papers (Koehler et al., 1994; Friedland, 1992; McKenna, 1993). We report three experiments attempting to distinguish between the two biases and establish their generality. The first exper iment demonstrates that, when predicting and judging unique events, th e two response tendencies are influenced by different factors. The sec ond and third experiments confirm that the tendency to overpredict des irable outcomes is uncorrelated with control, and that the illusion of control vanishes when multiple predictions are involved (Koehler ct a l., 1994). We conclude that desirability bias and illusion of control are two distinct response biases. Only under very special circumstance s are they affected by the same factors.