Stereotypes are a foundational construct in psychological science, often defined as beliefs concerning characteristic group attributes. We present a cognitive-ecological theory of social perception that predicts and explains why such characteristic attributes are likely negative, that is, why most stereotypes are negative. The theory assumes that, cognitively, people characterize groups by attributes that distinguish them from other groups. Ecologically, positive social information is more frequent (i.e., positivity  prevalence), and negative social information is more diverse (i.e., negativity diversity. If negative attributes are less frequent and more diverse relative to positive attributes, then they must be more likely to distinguish one group from another. Consequently, the attributes people see as characteristic of a group are likely to be negative. We illustrate the predicted stereotype negativity across two studies and two existing data sets. We then formalize the theory and illustrate it with simulations showing that rare attributes can be highly diagnostic of group membership while applying to only a minority of group members. Thus, the theory explains why most stereotype content is likely negative, despite the well-documented positivity prevalence, and why stereotypes may be diagnostic and comparatively accurate, despite being descriptively inaccurate. The theory explains stereotype negativity without requiring motivational derogation, essentialist group differences, or a general negativity bias, and it clarifies when positive stereotypes should occur. We also discuss the theory’s relation to dimensional models of stereotype content and consequences for interventions aimed at reducing stereotype negativity.

That is from a recent paper by Christian Unkelbach, Anne Irena Weitzel, and Hans Alves, via the excellent Kevin Lewis.