Partisan-Motivated Sampling: Re-Examining Politically Motivated Reasoning Across the Information Processing Stream

The United States is increasingly politically polarized, fueling intergroup conflict and intensifying partisan biases in cognition and behavior. To date, research on intergroup bias has separately examined biases in how people search for information and how they interpret information. Here, we integrate these two perspectives to elucidate how partisan biases manifest across the information processing stream, beginning with (a) a biased selection of information, leading to (b) skewed samples of information that interact with (c) motivated interpretations to produce evaluative biases. Across three experiments and four internal meta-analyses, participants (N = 2,431) freely sampled information about ingroup and outgroup members or ingroup and outgroup political candidates until they felt confident to evaluate them. Across experiments, we reliably find that most participants begin sampling information from the ingroup, which was associated with individual differences in group-based motives, and that participants sampled overall more information from the ingroup. This sampling behavior, in turn, generates more variability in ingroup (relative to outgroup) experiences. We find that more variability in ingroup experiences predicted when participants decided to stop sampling and was associated with more biased evaluations. We further demonstrate that participants employ different sampling strategies over time when the ingroup is de facto worse-obfuscating Real Group Differences-and that participants selectively integrate their experiences into evaluations based on congeniality. The proposed framework extends classic findings in psychology by demonstrating how biases in sampling behavior interact with motivated interpretations to produce downstream evaluative biases and has implications for intergroup bias interventions.