Judges limit the protection of anti-discrimination laws to cases involving purposeful discrimination, i.e., when defendants acted in order to discriminate against the plaintiff. Social psychological evidence for “implicit bias,” however, shows that people tend to take discriminatory actions even when it is not their intent to do so. Advancing an approach to legal analysis known as behavioral realism, scholars and anti-discrimination advocates argue that the legal protections ought to be expanded to reflect the scientific evidence or a justification offered as to why this should not occur. As a prescriptive jurisprudential tool, behavioral realism has successfully spawned a rich academic literature examining the implications of implicit bias for a wide range of legal doctrine, the veracity of the assumptions supporting the doctrine, and what those assumptions may imply. And educating people about implicit bias, including lawyers and judges, persuades many of them to seek out and adopt ways to voluntarily address its effects in themselves. But, to the extent behavioral realism has been interpreted as a descriptive model suggesting that proffering psychological science will prompt meaningful change in anti-discrimination doctrine, it has thus far proven ineffective. Judges presented with the latest information about and best evidence of implicit bias generally refuse to find defendants liable for its effects. I argue that the expectation that educating judges about the psychological science of implicit bias will lead to an expansion of anti-discrimination rights is ineffective because it relies upon a model of the legal system that is jurisprudentially and psychologically simplistic. Thus, in making their case, advocates often rely too much on the science and pay too little attention to identifying and finding ways to overcome barriers other than a hypothesized judicial ignorance of implicit bias. To address the shortcoming, and encourage and lay a foundation for the next phase of research and advocacy on anti-discrimination law and psychology, I identify and discuss several additional barriers to effective use of psychological science to advance anti-discrimination law and discuss their implications for use of the science of implicit bias to drive doctrinal change.