It happens because I'm watching it: Observing an uncertain event can affect subjective probability judgments

Abstract

A longstanding body of research has investigated various factors that bias subjective probability judgments. The current research explores a novel bias in judgments of probability-that observing an event affects probability estimation of the event's outcome. Our findings from multiple online and laboratory experiments demonstrate that individuals overestimate the likelihood of a positive outcome occurring when they observe (vs. do not observe) the uncertain event unfolding in front of them. Study 1 explores the effect of watching on probability estimation using a random card draw conducted in an auditorium. Studies 2 and 3 use an online procedure to further demonstrate the effect. In Study 4 we manipulated an illusory sense of control followed by a football game scenario and in Study 5 we used a live versus previously recorded urn game to further investigate the watching effect. We suggest that illusion of control, wishful thinking, and availability are among the possible explanations for this effect.