Outgroup Homogeneity Bias: 'Tendency to assume that the members of other groups are very similar to each other, particularly in contrast to the assumed diversity of the membership of one's own group.'

The spreadsheet's definition of outgroup homogeneity bias is accurate and worth stating plainly: it is a real, replicated finding in social psychology (Quattrone & Jones 1980, *Journal of Personality and Social Psychology*; Linville, Fischer & Salovey 1989), and any group, religious or secular, is susceptible to it. Where the implied application to Christianity goes wrong is in treating this as a one-directional problem. First, Romans 1:18-32 is not an empirical psychological generalization about individual unbelievers' inner states ('every atheist secretly knows and suppresses theism'); it is a theological claim about the *structural* human condition under general revelation — that creation itself renders God's 'eternal power and divine nature' evident (v. 20), so that idolatry and moral corruption are culpable rather than innocent ignorance. That is a claim about what is available to be known, not a psychological profile flattening every individual skeptic's biography and reasoning process (see Douglas Moo, *The Epistle to the Romans*, NICNT, on the corporate/representative rhetorical register of Rom 1-3). Second, the bias cuts both ways, and demonstrably so: skeptical literature routinely flattens 'religious believers,' 'fundamentalists,' or 'Christians' into a single caricature (anti-intellectual, literalist, tribal) that erases the actual diversity of Augustinian, Thomistic, Reformed, Orthodox, Wesleyan, and critical-scholarly Christian positions — including sharp internal disagreements over inerrancy, atonement theory, and biblical interpretation. Invoking the bias asymmetrically, only against the outgroup one dislikes, is itself an instance of the very bias being described. A fair use of the concept requires applying it symmetrically to one's own reasoning about 'religious people' as a category.

Christian theology has internal resources for resisting this bias that a purely naturalistic account of belief-formation does not obviously provide: the doctrine of the image of God grounds a principled reason to expect genuine moral and intellectual diversity, even brilliance, among non-believers (common grace, general revelation), rather than requiring believers to treat outsiders as uniformly deceived or degraded. Historic apologetics (from Justin Martyr's logos spermatikos onward) has explicitly made room for real insight and virtue outside explicit Christian confession.