Moral, social, political, and other “nonepistemic” values can lead to bias in science, from prioritizing certain topics over others to the rationalization of questionable research practices. Such values might seem particularly common or powerful in the social sciences, given their subject matter. However, I argue first that the well documented phenomenon of motivated reasoning provides a useful framework for understanding when values guide scientific inquiry (in pernicious or productive ways). Second, this analysis reveals a parity thesis: values influence the social and natural sciences about equally, particularly because both are so prominently affected by desires for social credit and status, including recognition and career advancement. Ultimately, bias in natural and social science is both natural and social—that is, a part of human nature and considerably motivated by a concern for social status (and its maintenance). Whether the pervasive influence of values is inimical to the sciences is a separate question.
We have seen how many of the putative biases that affect science can be explained and illuminated in terms of motivated reasoning, which yields a general understanding of how a researcher’s goals and values can influence scientific practice (whether positively or negatively). This general account helps to show that it is unwarranted to assume that such influences are significantly more prominent in the social sciences. The defense of this parity claim relies primarily on two key points. First, the natural sciences are also susceptible to the same values found in social science, particularly given that findings in many fields have social or political implications. Second, the ideological motivations that might seem to arise only in social science are minor compared to others. In particular, one’s reasoning is more often motivated by a desire to gain social credit (e.g. recognition among peers) than a desire to promote a moral or political ideology. Although there may be discernible differences in the quality of research across scientific domains, all are influenced by researchers’ values, as manifested in their motivations.