This commentary examines the issue of judicial bias in response to the chapter, The Psychology of the Trial Judge, by Morris Hoffman. With a focus on retributive punishment judgments, it questions whether human decision makers, including judges, can rely on their powers of rationality, or whether such judgments are fundamentally emotional and intuitive. I begin with the observation that we, as a society, do not have a clear conceptual understanding of why we punish criminals. Further, there are good reasons to think that retributive attitudes might be the expression of psychological biases, and this poses problems for the prospect of rational punishment. At the least, a coherent justification for punishment should be informed by an empirical understanding of the causes of these psychological biases, including their evolutionary origins. Evolutionary scholarship suggests that retributive attitudes evolved to generate consequentialist outcomes like deterrence, but they did so to achieve a competitive advantage between individuals, not to protect society as a whole. Such findings suggest that our retributive attitudes today might not always function in ways that are best for society. Thus, understanding why our punishment psychology evolved in the ways that it did, we as a society can more cogently evaluate whether we embrace those reasons or reject them. An appreciation of our evolved psychology of punishment can also provide a framework for unifying the rival legal justifications for punishment. From this perspective, retributive and consequentialist motives for punishment are not completely incompatible. Rather, they are different levels of analysis for describing our universal punishment psychology.