Objection provides a penetrating and entertaining analysis of how disgust works, why it evolved, how it influences morality, and how it underlies facets of our legal system. The book is written with a critical eye toward American legal theory and recent events in American politics, with pertinent examples involving President Donald Trump and late U.S. Supreme Court Justice Antonin Scalia. With expertise in psychology, evolutionary biology, neuroscience, and law, Debra Lieberman and Carlton Patrick reverse-engineer the universal emotion of disgust and then proceed to warn us of its dangerous manifestations in the law.
Lieberman and Patrick’s treatise on disgust offers a compelling explanation of how and why the emotion works the way it does (i.e., the authors explain disgust at both the proximate and ultimate levels of analysis). After elucidating the functional architecture of disgust, they venture into the muddier waters of moral psychology and the ways in which disgust can feature as both an input into and an output of our intuitive ethics.
These first two sections of the book are replete with visual models that give the reader a sense of how disgust is related to other psychological variables, such as sexual value (p. 94) and social value (p. 121). In the third and final section of the book, Lieberman and Patrick analyze the many ways disgust pervades and influences the law. The bulk of Objection consists of these three interdependent sections. The book concludes with a particularly thought-provoking chapter arguing that we should be deeply opposed to allowing disgust to dictate our morality and influence our legal systems.
The first section of the book explores the evolved architecture of disgust: how it works and why it works in the way that it does. Lieberman and Patrick demonstrate how impressive disgust is in the breadth of its elicitors and the many different domains of experience that it affects: eating, physical contact, sex, and morality. Their evolutionary treatment of disgust begins with the necessary scaffolding for those who are new to the field. Lieberman and Patrick clearly and concisely explain key ideas related to instinct blindness, selection pressures, and the leading evolutionary psychological approach to emotions. The authors are careful not to overwhelm the reader with unnecessary tangents related to research and theory on disgust. The authors even encourage the reader to skip one chapter (Chapter 7, “A New Model”) should it prove too academic or dense. However, even this chapter is brief, important, and interesting in its depiction of the overlap between the leading frameworks for understanding disgust.
One of the many contributions of the book is a comprehensive analysis of the ways in which disgust regulates our moral compass. The existence and importance of moral disgust has been disputed and debated, but this may be because until the publication of Objection, there was no central resource to consult for a comprehensive and coherent presentation of the emotion of moral disgust. The authors tackle the central question of whether moral disgust reflects a diversity of phenomena underlain by several psychological mechanisms or whether it is produced by a single psychological mechanism. They suggest that they are leaning away from the latter idea (but not ruling it out) and moving toward the notion that what we currently call “moral disgust” represents many phenomena produced by different psychological mechanisms. The authors argue that “moral disgust” seems to be one of many outputs signaling allegiance to moral norms and encouraging avoidance of those who are perceived as low in contact, sexual, or social value.
Lieberman and Patrick demonstrate that disgust—by way of coloring what we deem right or wrong—influences laws in ways that perpetuate conflict in part by triggering our darker tendencies toward exploitation, marginalization, and elimination. Consonant with Wrangham’s recent book The Goodness Paradox (Reference Wrangham2019) and Kurzban and Leary’s research (Reference Kurzban and Leary2001) on moral conscience, Objection focuses on these tendencies and related darker aspects of our moral psychology. Lieberman and Patrick also explain why women are often disgusted by a range of sexual advances that men not only think are acceptable but actively welcome. In the age of the #MeToo movement, the authors’ discussion of these disgust-related sex differences is likely to be controversial. Nevertheless, the more our legal system is informed by the leading scientific explanation of sex differences in sexual disgust, the better equipped we will be to produce laws that reduce sexual conflict.
Marrying legal theory to the evolutionary psychology of disgust highlights how many of our laws seem rooted not in rational thought, but rather in our psychology of “gross equals bad.” An understanding of the gut objections that affect our legal systems exposes some glaring “post-hoc rationalizations for intuitive reactions” (p. 185). Lieberman and Patrick posit many thought experiments that illustrate the irrationality of our disgust-related moral judgments. For example, they ask the reader to imagine “a rare disease in which a person’s body ceases to age past age eight even while their mind ages at the normal rate—would we be untroubled by the thought of an adult having sex with a 22-year-old person if he or she still had the body of an eight-year-old (a body lacking cues to an elevated mate value and, hence, elevated sexual value)?” (p. 183). These hypotheticals convey to the rational reader, as the trolley problem conveys to the utilitarian reader, that doing what one believes is rationally right can sometimes feel repulsive.
Lieberman and Patrick point out that disgust influences the law and legal practice in ways that are often unrecognized and unregulated (e.g., when prosecutors use disgust-inducing descriptors of the accused). The authors describe fascinating research showing that gruesome photographic evidence tends to (a) increase the harshness of verdicts, (b) increase jury members’ confidence in their verdicts, and (c) decrease the amount of evidence needed to reach a verdict (Bright & Goodman-Delahunty, Reference Bright and Goodman-Delahunty2006; Douglas et al., Reference Douglas, Lyon and Ogloff1997). Lieberman and Patrick also point out that two of the four traditionally used categories of defamation are disgust related: “loathsome disease” and “serious sexual misconduct.” Amusing examples from centuries ago, such as “Thou wert laid of the French pox” (p. 169), both entertain and allude to the fact that disgust has long affected the law and legal practice. In both instances of defamation and the exclusion of gruesome photographic evidence, the law has already acknowledged and attempted to curb the prejudicial effects of disgust.
Objection is well written, entertaining, and accessible—it will surely be enjoyable to nonacademic readers. At the same time, it is educational and scholarly and could serve as the primary reading in an undergraduate or graduate-level psychology course. Written in a lively manner and devoid of repetition, Objection is more often delightful than disgusting. Objection is peppered with amusing stories. For example, the authors relay a funny anecdote about the late anthropologist Napoleon Chagnon, who used the psychology of disgust to his advantage while studying the indigenous Yanomamö of Venezuela. Chagnon was worried about an onlooker who wanted a share of his frankfurters. When asked what he was eating, Chagnon said “beef,” and when asked what part of the animal that was, he said “guess,” which successfully repulsed the onlooker and left Chagnon to eat his frankfurter in peace (p. 199). This anecdote also illustrates how we are biologically prepared to learn different disgust cues (in this case, Chagnon initially learning as a child that hotdogs are not gross). Thus, disgust’s context sensitivity renders it inherently flexible.
Finally, in warning against the “appeal to nature” fallacy, Lieberman and Patrick go back to basics and quote Hume’s famous passage regarding how ought and ought not do not follow from is and is not. The authors then ask, “Over time many of our folk-scientific intuitions—intuitions that perhaps worked for hunter-gatherers navigating ancestral social environments—have been exposed as flawed approximations of reality. Why should we give our moral intuitions—especially intuitions that were in part selected to coordinate exploitation—the benefit of the doubt?” (p. 194). This is a reasonable argument; there is no special reason to regard our moral intuitions as veridical. Nonetheless, we may still be able to marshal this emotion to benefit society by triggering moral reactions that reduce smoking, curb obesity, and limit our society’s endorsement of factory farming. While we should be wary of allowing disgust to drive our morality and our legal system in an unreflective manner, we could maybe consciously and intentionally use the emotion to enact positive change. This reinforces how important and wide-ranging the emotion of disgust is—a topic to which Objection does justice.
