Chapter 15: Metaphors We Kill By

Sapolsky explores how humans confuse symbols and metaphors with literal reality, a uniquely human trait that drives both atrocities and acts of peace. Sapolsky begins with examples of people dying or killing over cartoons of Muhammad, flags at Gettysburg, gang colors, hunger strikes, or even karaoke songs—illustrating how symbols acquire sacred value. Unlike animals, humans live in a world of symbolic meaning, where language, metaphor, and imagery collapse the distance between representation and reality. This capacity evolved recently, leaving our brains improvising with existing circuits, such as the insula and anterior cingulate cortex, to process metaphorical experiences as if they were literal. The chapter explains how pain, disgust, and purity reveal this overlap. The anterior cingulate cortex processes both physical pain and social pain (like rejection), while the insula responds not only to rancid food but also to moral violations, producing visceral disgust at injustice or immorality. This connection explains phenomena like the “Macbeth effect,” where recalling immoral acts increases the desire to wash physically, as if cleansing moral failings. Experiments show that hand-washing after unethical acts reduces subsequent prosocial behavior by removing the drive to “make amends.” Studies also reveal that physical sensations of warmth, hardness, or cleanliness unconsciously shape judgments of others as kind, rigid, or trustworthy. Our metaphors of “warm-heartedness,” “hard-nosed,” or “clean conscience” reflect literal bodily sensations embedded in cognition. Sapolsky then shows the dark side of metaphor. Propaganda exploits symbolic associations to dehumanize out-groups, activating insula disgust. The Rwandan genocide exemplifies this, where Tutsis were labeled “cockroaches,” fueling machete massacres at rates five times faster than the Holocaust. Dehumanizing metaphors—Others as vermin, disease, or filth—collapse symbolic disgust into literal extermination, unleashing genocidal violence. This demonstrates how metaphors can weaponize biology to justify atrocity. Yet Sapolsky also emphasizes a glimmer of hope: symbolic concessions can foster peace. Anthropologist Scott Atran’s research on sacred values shows that conflicts are often sustained not by material disputes but by symbolic ones—honor, apologies, recognition of suffering. Peace processes succeed when symbolic gestures acknowledge sacred values, as seen in King Hussein’s eulogy for Rabin, Mandela’s embrace of Afrikaner culture, or symbolic reconciliations in Northern Ireland. Such acts transform metaphors of enmity into metaphors of shared humanity. Ultimately, Chapter 15 reveals that our brains’ confusion of metaphor and reality is a double-edged sword. It can unleash dehumanization and mass violence, but it can also enable reconciliation, unity, and peace when sacred symbols are respected. The challenge is learning to harness metaphor for cooperation rather than destruction.