Instrumental Bias in Motivated Reasoning: More When More Is Needed

Abstract Decision makers must often make judgments in an environment in which they have a strong motivation to reach a particular conclusion. While normative theory would indicate that they should use available information to make their most accurate judgment without being influenced by the conclusion or outcome it may imply, evidence from the social judgment literature suggests that motivation does bias the judgment process. Specifically, decision makers motivated to support a particular conclusion tend to adopt information processing strategies most likely to yield the desired conclusion. We propose and empirically demonstrate two extensions to the motivation literature. First, we argue that motivated reasoning isinstrumental,meaning motivated decision makers bias their judgments more or less as needed to support the desired conclusion, subject to “reasonableness” constraints. Second, we propose that motivated decision makers exhibitconfidence bolsteringand thereby remain at least as confident as non-motivated decision makers in their biased estimates. We illustrate that motivated subjects even report confidence in utilizing these estimates outside the original motivating context. We investigate motivational effects within a business context involving forecasting, strategic decision making, and new product introductions. We explore the impact of motivation on quantitative forecasts and estimates, rather than on social judgments and perceptions. In addition, we go a step beyond the judgment phase to demonstrate that motivation influences choice.