Philip Dwyer's (2022) Violence: A Very Short Introduction highlights some of the most horrific acts of violence in the human behavioral repertoire, including uxoricide, infanticide, and genocide, arguing that rates of specific acts of violence have either increased or remained the same throughout human history. Dwyer is Professor of History and the founding Director of the Centre for the Study of Violence at the University of Newcastle (Australia). He has published extensively on the Napoleonic era and recently served as editor of The Darker Angels of Our Nature: Refuting the Pinker Theory of History and Violence (Dwyer, 2018; Dwyer & Micale, 2021). Much of the empirical work cited by Dwyer in Violence: A Very Short Introduction focuses on violence from the mid-eighteenth century onward, with some reference to archeological evidence of homicide. Dwyer neglects research on violence among nonhuman animals, perhaps because it does not suit his definition of violence. Dwyer contends that violence is an ambiguous and culturally relative concept, defining the term “violence” as “what a society acknowledges as violent” (p. 2). Dwyer’s definition of violence encompasses such acts as damage to a cultural heritage site and leaves readers questioning if a slap across the face can be deemed “violent” when there is community support for the slap. The supposition that wife-beating did not qualify as violence until the nineteenth century, due to a decrease in the social acceptability of wife-beating, is particularly baffling; perhaps battered wives in the eighteenth century would disagree (Dwyer, 2022, p. 17). Apparently, according to Dwyer, an intentional act that physically harms another being is only violent when widely condemned by others. The perplexing definition of violence offered by Dwyer is congruous with the bewildering nature of arguments that he presents throughout the book.

The interpretation of violence data in Violence: A Very Short Introduction would have benefitted from the application of a guiding theoretical framework, and evolution by natural selection is a well-established theory of the nature of life (Daly & Wilson, 1988). Humans are complex evolved systems with traits, including psychological traits, that have been “designed” to solve recurrent adaptive problems over evolutionary history (Daly & Wilson, 1988). Violence is particularly amenable to applications of evolutionary theory because it is well documented across cultures and evident throughout human history, suggesting that universal evolved psychological mechanisms may motivate some acts of violence (Daly & Wilson, 1988). Dwyer's (2022) thesis that acts of violence must be understood within specific cultural contexts can be effectively reevaluated through the application of an evolutionary theoretical framework.

There is an abundance of data consistent with an evolutionary psychological perspective on intimate partner violence, the topic of Chapter 2 in Violence: A Very Short Introduction. “Most forms of intimate and gendered violence are carried out by men against women” (Dwyer, 2022, p. 16) and parental investment theory (Trivers, 1972) may provide insight into the gendered nature of intimate partner violence. Parental investment theory posits that the different selection pressures faced by males and females are the result of biological asymmetries in reproduction (Trivers, 1972). Paternity uncertainty is an adaptive problem faced exclusively by men and investing in genetically unrelated offspring is extraordinarily costly. Therefore, throughout human evolutionary history, men that experienced sexual jealousy, monitored their partner’s sexual fidelity, attempted to control her reproductive capacities, and inflicted costs on her to prevent cuckoldry reaped selective advantages. An evolutionary psychological perspective informs the prediction that women who pose a greater risk of extrapair reproduction are at greater risk of intimate partner violence and homicide. Consistent with this prediction, research reports that females from 15 to 34 years of age are at the greatest risk of becoming intimate partner homicide victims, a notable finding considering the lifetime trajectory of female fertility (Pratt & Deosaransingh, 1997). In an analysis of cross-national spousal homicide data, Wilson and Daly (1993) found that the combination of physical and legal separation posed the greatest risk for murder by an intimate partner. According to Daly and Wilson (1988), intimate partner homicide is not the adaptive target of evolved psychological mechanisms but is a byproduct of mechanisms selected for their nonlethal outcomes, such as controlling an intimate partner (Goetz et al., 2008; Wilson et al., 1995). Dwyer (2022) thus unknowingly endorses Daly and Wilson (1988) view when writing that “The perpetrator is communicating to the victim, through an act that inflicts pain or control, that they ‘own’ and dominate them” (p. 19). The universally gendered nature of intimate partner violence is more parsimoniously explained by an evolutionary psychological perspective than by Dwyer’s thesis that violence must be understood within a specific cultural context.

Infanticide is among the most tragic acts of violence perpetrated by humans, so it is imperative to critically evaluate the premise that infanticide is solely the result of cultural contexts (Dwyer, 2022). Infanticide applies to children under the age of 1 year, whereas neonaticide refers to the killing of an infant within 24 h of birth (Brookman & Nolan, 2006; West, 2007). Findings from 12 countries with detailed data on filicide perpetration show that mothers were the perpetrators of the majority of infanticides (71.7%) and 100% of neonaticides (Stöckl et al., 2017). Friedman and Resnick (2009) found that most perpetrators of neonaticide were young, unmarried women from disadvantaged backgrounds who reported fear of the consequences of pregnancy. Children, particularly infants, require an immense amount of energy and resources which may be too costly for a young, single female to bear. Women across cultures report a preference for men who are high on the dimensions of status and wealth, likely the result of biological asymmetries in reproduction (Conroy-Beam et al., 2015). Females must gestate and nurse offspring, whereas males only need to invest the energy required to produce a single ejaculate to reproduce, making it risky for females to reproduce with a male that lacks desirable qualities such as access to the resources required to care for children (Bateman, 1948; Trivers, 1972). Females are unable to produce additional offspring while gestating and nursing, whereas males can produce offspring with multiple mates in quick succession, contributing to the relatively higher reproductive costs shouldered by women (Bateman, 1948; Trivers, 1972). Female mate value immediately declines once she has a child, so it can be very harmful to future mating prospects to have an infant (Daly & Wilson, 1988). A large parental investment in current offspring decreases the resources available to invest in future offspring as any resources provisioned to current offspring cannot be invested in future offspring, so the larger reproductive window of younger women may dampen the adaptive costs of infanticide. Still, maternal infanticide is typically a profoundly painful experience for mothers, with many perpetrators attempting or completing suicide after committing infanticide (Kauppi et al., 2008). Humans rely on groups for survival and are relatively ineffective at surviving alone compared to other species, so the consequences of unwanted pregnancy and subsequent social isolation can be dire for young women. Dwyer’s notion that infanticide is culturally dependent discounts the insights provided by an evolutionary psychological perspective.

Dwyer's (2022) contention that violence has not decreased over human history may be the result of conflating raw numbers and rates. Although more humans are subject to violence today than throughout most of human history due to human population growth, individuals are at a lower risk of violence victimization today than throughout human evolutionary history (Pinker, 2011). Dwyer appears to acknowledge this reality when stating that “most of us will never find ourselves in a situation where we must make a choice between killing and not killing” (p. 91), yet much of Violence: A Very Short Introduction is focused on refuting Pinker (2011) thesis that rates of violence have declined throughout human evolutionary history. Dwyer asserts that Pinker uses “statistics to posit a view of the pre-modern world as brutal and bloody” (p. 13), contending that few historians endorse Pinker’s interpretation of historical records. A history degree is not a prerequisite for accurately interpreting historical data, however. Dwyer repeatedly claims that violence statistics, both historical and contemporary, are inaccurate and difficult to collate, leaving readers unsure about the validity of the violence statistics presented by Dwyer and his corresponding arguments. According to Dwyer, “there are more slaves in the world today than existed during the whole of the Atlantic slave trade” (p. 111), yet “we simply do not know” (p. 110) the number of human trafficking and slavery victims alive today. Dwyer’s lofty claim about the greater number of slaves in the world today is based on data from the Global Slavery Index that is produced by the Walk Free Foundation. The Global Slavery Index has been widely criticized for methodological problems that call into question the replicability and validity of the data, such as the use of survey data from seven countries to extrapolate data from 155 other countries (Guth et al., 2014). Despite the questionable sources utilized by Dwyer, Violence: A Very Short Introduction is rife with certitude yet devoid of theory.

Although we cannot in good conscience recommend this book to readers interested in an accurate reflection of the scientific state of the study of violence, Violence: A Very Short Introduction contains some compelling arguments worth noting. In Chapter 4, Dwyer (2022) discusses the decrease in judicial killings and the abolition of capital punishment in many countries throughout the nineteenth and twentieth centuries, a well-founded observation that supports the idea that violence has declined throughout human evolutionary history. Similarly, Dwyer’s statement that “religion is not necessarily the cause of violence, but it often offers a moral justification” (p. 60) is thought-provoking and worth exploring further. Religious views may not be inherently more dangerous than secular views, but it is possible that religious texts have been used as moral justification for violence more often than secular texts. Violence that is purported to be perpetrated in the name of religion should be critically examined as it is possible that religion is not the true motivation. For example, the motive for the violent Spanish colonization of the Americas in the name of Christianity may be better explained by interests in resource acquisition. Overall, Violence: A Very Short Introduction is a frustrating but occasionally provocative read.