Research on the detection of deception consistently documents this "truth bias." In the typical study, participants observe people making statements and are asked to indicate, each time, whether they think the person is lying or telling the truth. Measuring whether people believe others should be difficult to do accurately, because simply asking the question disrupts the tendency to assume that other people are telling the truth. It gives participants a reason to wonder. And yet, in our statistical summary of more than 200 studies, Charles F. Bond Jr. and I found that participants still believed other people more often than they should have — 58 percent of the time in studies in which only half of the statements were truthful. People are biased toward believing others, even in studies in which they are told explicitly that only half of the statements they will be judging are truths.