Interpersonal expectations originate because they reflect rather than cause social reality

From the abstract of Précis of Social Perception and Social Reality: Why Accuracy Dominates Bias and Self-Fulfilling Prophecy by Lee Jussim.

Social Perception and Social Reality reviews the evidence in social psychology and related fields and reaches three conclusions: 1. Although errors, biases, and self-fulfilling prophecies in person perception, are real, reliable, and occasionally quite powerful, on average, they tend to be weak, fragile and fleeting; 2. Perceptions of individuals and groups tend to be at least moderately, and often highly accurate; and 3. Conclusions based on the research on error, bias, and self-fulfilling prophecies routinely greatly overstates their power and pervasiveness, and consistently ignores evidence of accuracy, agreement, and rationality in social perception. The weight of the evidence – including some of the most classic research widely interpreted as testifying to the power of biased and self-fulfilling processes – is that interpersonal expectations related to social reality primarily because they reflect rather than cause social reality. This is the case not only of teacher expectations, but also social stereotypes, both as perceptions of groups, and as the bases of expectations regarding individuals. The time is long overdue to replace cherry-picked and unjustified stories emphasizing error, bias, the power of self-fulfilling prophecies and the inaccuracy of stereotypes with conclusions that more closely correspond to the full range of empirical findings, which includes multiple failed replications of classic expectancy studies, meta-analyses consistently demonstrating small or at best moderate expectancy effects, and high accuracy in social perception.

If robustly true, this could have saved me a lot of arguments over the years.