Introduction
This essay presents a detailed book report on Dave Grossman’s seminal work, On Killing: The Psychological Cost of Learning to Kill in War and Society, first published in 1995. Written from the perspective of a history undergraduate, this report aims to summarize the core arguments, themes, and historical implications of Grossman’s text, while situating it within the broader study of military history and the psychological impacts of warfare. Grossman’s book offers a profound exploration of the human reluctance to kill, the mechanisms that enable soldiers to overcome this resistance, and the long-term psychological consequences of such actions. This essay will examine Grossman’s key assertions under thematic headings, including the innate resistance to killing, the conditioning techniques used in military training, and the societal and historical ramifications of his findings. By critically engaging with the text, the report will also assess the relevance and limitations of Grossman’s arguments for the study of history, supported by academic commentary and evidence.
Overview of “On Killing” and Its Historical Context
Dave Grossman, a retired Lieutenant Colonel in the U.S. Army and a former psychology professor, wrote On Killing to address a relatively underexplored aspect of military history: the psychological barriers that soldiers face when required to kill in combat. The book draws on historical case studies, psychological research, and personal anecdotes to argue that humans possess a natural aversion to killing their own kind, a trait that has significant implications for how wars are fought and how soldiers are trained. Historically, Grossman builds on the work of S.L.A. Marshall, whose studies during World War II suggested that a significant proportion of soldiers—up to 85%—did not fire their weapons in combat due to this innate resistance (Marshall, 1947, cited in Grossman, 2009). Grossman places this phenomenon within a long historical arc, from ancient battles to modern conflicts, suggesting that the psychological challenges of killing are a constant across time, even as warfare has evolved.
One of the strengths of Grossman’s approach is his use of historical examples to ground his psychological arguments. For instance, he refers to accounts from the American Civil War and World War I, where soldiers were observed loading and reloading weapons without firing, a behavior he attributes to subconscious avoidance (Grossman, 2009). However, a limitation in this historical contextualization, as some scholars note, is the lack of extensive primary source analysis beyond Marshall’s controversial data, which has been debated for its methodological rigor (Engen, 2008). Nevertheless, Grossman’s work remains a valuable contribution to military history, as it bridges the gap between psychological theory and historical experience, offering a lens through which to reinterpret soldiers’ behaviors in past wars.
The Psychological Resistance to Killing
Central to On Killing is Grossman’s assertion that most humans are instinctively reluctant to kill, a trait he argues is rooted in evolutionary and social conditioning. He posits that this resistance is not merely a product of cowardice or lack of training but rather a deep-seated psychological barrier that must be overcome for effective combat performance. Grossman categorizes the factors that reinforce this aversion, including the fear of accountability, moral upbringing, and the physical and emotional proximity to the enemy (Grossman, 2009). For example, he explains that killing at close range, such as with a bayonet, is far more psychologically taxing than firing a weapon from a distance, a phenomenon evidenced in historical accounts of hesitation during hand-to-hand combat in the Napoleonic Wars.
This theme is particularly relevant to historians studying the human experience of war. By highlighting psychological resistance, Grossman challenges traditional military histories that often focus on strategy and tactics, urging a deeper examination of soldiers’ internal conflicts. However, his argument is not without critique. Some psychologists and historians argue that Grossman overgeneralizes this resistance, as cultural and individual differences can significantly influence attitudes toward killing (Bourke, 1999). Despite this limitation, his exploration invites historians to consider the emotional toll of warfare, a perspective that enriches narratives of conflict beyond mere statistical or political analysis.
Conditioning and Training: Overcoming the Barrier
Grossman dedicates a significant portion of On Killing to examining how military institutions have historically adapted training methods to bypass soldiers’ natural aversion to killing. He argues that modern armies, particularly post-World War II, have employed psychological conditioning techniques—such as operant conditioning and desensitization through realistic simulations—to increase firing rates and combat effectiveness. For instance, he contrasts the low firing rates of World War II soldiers with the significantly higher rates during the Vietnam War, attributing this shift to innovations in training that made killing more reflexive (Grossman, 2009). This included the use of human-shaped targets rather than bullseyes, which conditioned soldiers to associate firing with enemy combatants.
From a historical perspective, this argument sheds light on the evolution of military practices and the intersection of psychology and warfare in the 20th century. Grossman’s analysis provides a framework for understanding why certain wars, such as Vietnam, were marked by unprecedented levels of violence and trauma among soldiers. Yet, while his evidence on training methods is compelling, it is primarily anecdotal and reliant on American military contexts, potentially limiting its applicability to other nations’ historical experiences (Engen, 2008). Nonetheless, his discussion prompts historians to investigate how psychological innovations have shaped military outcomes and soldiers’ experiences across different epochs.
Societal and Psychological Consequences
Another critical theme in On Killing is the aftermath of killing, both for individual soldiers and society as a whole. Grossman argues that even when soldiers are conditioned to kill, the act often results in profound psychological damage, manifesting as guilt, post-traumatic stress disorder (PTSD), and moral injury. He draws parallels between historical accounts of “shell shock” in World War I and modern diagnoses of PTSD, suggesting that the trauma of killing is a timeless consequence of war (Grossman, 2009). Additionally, he controversially extends his analysis to civilian life, linking violent video games and media to increased societal aggression, though this claim has been met with skepticism by some scholars for lacking robust empirical support (Bourke, 1999).
For historians, Grossman’s focus on trauma connects to broader studies of war’s human cost, encouraging a shift from glorifying combat to understanding its devastating effects. However, his societal arguments, particularly on media violence, are less convincing due to their speculative nature and tangential relevance to military history. Despite this, his emphasis on psychological consequences remains a vital contribution, aligning with historical inquiries into veterans’ reintegration and mental health policies in post-war societies.
Conclusion
In conclusion, Dave Grossman’s On Killing offers a thought-provoking exploration of the psychological dimensions of warfare, emphasizing the human reluctance to kill, the mechanisms used to overcome it, and the lasting consequences of such actions. From a historical perspective, the book enriches our understanding of soldiers’ experiences across various conflicts, challenging traditional narratives by foregrounding emotional and psychological factors. While Grossman’s arguments are grounded in compelling historical examples and psychological theory, they are occasionally limited by overgeneralization and a reliance on contested data, such as Marshall’s firing rates. Nevertheless, On Killing remains a significant text for history students, as it bridges military history with psychology, prompting a deeper examination of war’s human toll. Its implications extend beyond academia, urging societies to consider the ethical and emotional costs of preparing individuals for combat—a consideration that remains relevant in contemporary discussions of warfare and veteran care. This book report, therefore, underscores the value of Grossman’s work as a starting point for further historical inquiry into the intersection of mind and conflict.
References
- Bourke, J. (1999) An Intimate History of Killing: Face-to-Face Killing in Twentieth-Century Warfare. Granta Books.
- Engen, R. (2008) Killing for their country: A new look at ‘killology’. Canadian Military History, 17(2), 54-61.
- Grossman, D. (2009) On Killing: The Psychological Cost of Learning to Kill in War and Society. Back Bay Books.
