Implicit bias is perhaps the most prevalent type of discrimination in the modern workplace. Despite this, there is no adequate framework that incorporates implicit bias into a theory of Title VII discrimination.
Implicit bias theoretically fits well into a disparate impact theory because one need not prove intentionality when proving disparate impact. However, there are several problems. First, the lodestar of disparate impact discrimination is the existence of a facially neutral employer policy. Unconscious discrimination is not (indeed, cannot) be an employer policy. Second, implicit bias operates on an individual level, whereas disparate impact is meant to address business-wide policies. Even if you could prove that an individual has implicit bias, that still would not prove the existence of a business-wide policy that amounts to discrimination.
Disparate treatment has a less attractive theoretical framework because of the importance courts attach to proving that the protected trait actually motivated the adverse employment action. Simply put, this is difficult to do based off of an IAT. Even if an IAT showed, and the court accepted as fact, the presence of implicit bias in an employer it would still not prove that the employer's particular action that led to the lawsuit happened because of implicit bias. Nonetheless, it is under disparate treatment theory that implicit bias has had the most success.
Some judicial rejections of implicit bias have come without reference to the probative value of its evidence. These two cases are representative of what most rejections of implicit bias look like.
Cognitive psychology is a science, which means the evidence it produces is subject to particular evidentiary rules, most notable the Daubert standard. Two recent cases have cast doubt on whether evidence of implicit bias is admissible at all. This is important because unless evidence of implicit bias can be presented in court, it matters not if a theory can be fit to accommodate it.
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