Symmetrical one-on-one fights are a neglected prerequisite for weapon arms races

Evidence

We’ve identified two of the three critical ingredients for arms races: intense competition, generally arising among males as they battle for access to females, and ecological situations that cause resources to be localized and economically defensible. There’s one final ingredient, and it involves the details of the fights themselves—the way that males face each other in battle. Males must face each other one on one, rather than all together in a scramble. For bigger weapons to perform better than smaller ones, the battles must be matched and “symmetrical,” with comparably armed contestants challenging each other face-to-face. Oddly, this last ingredient has been almost entirely overlooked by biologists. To appreciate its significance, we must turn instead to attrition models of military forces, and to the century-old insights of an eclectic automotive and aeronautical engineer. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 226

Categorization

• XREF: The military attrition-model bridge is exactly the animal-human warfare parallel the reader wants; connects to Lanchester’s square law. — connects to: Concentrating simultaneous fire disfavors large weapons while duels favor them; Arms races inevitably stall as weapon costs neutralize reproductive benefits — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 432; Cheap weapons let untrained commoners overcome heavily armored elites (+16 more)
• QUESTION: Worth chasing: why did biologists overlook matched one-on-one combat when it is so structurally important? And how do scramble fights in nature break the symmetry assumption?
• corroborated: 2 independent passages support this claim — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 226

Related

• State arms races mirror single male-male animal contests, not evolutionary turnover (similarity 0.88)
• Specific conditions are required before weapons escalate into an arms race (similarity 0.88)
• One-on-one duels favor weapon evolution while chaotic scrambles do not. (similarity 0.87)
• Medieval combat structured even battlefield clashes as ritualized one-on-one duels (similarity 0.87)
• Three conditions must align to trigger an animal weapons arms race. (similarity 0.87)
• Concentrating simultaneous fire disfavors large weapons while duels favor them (similarity 0.85)
• Animal and human fights both hinge on whether duels or gang-ups occur (similarity 0.85)
• Fortification-artillery escalation mirrors predator-prey arms races, not rival contests (similarity 0.85)
• Cheap weapons let untrained commoners overcome heavily armored elites (similarity 0.85)
• When balancing selection fails, bigger weapons win every round and escalate the race. (similarity 0.84)
• Balancing selection normally curbs weapon size until some lineages escape into runaway arms races (similarity 0.84)
• Weapons innovations trigger arms races in ships just as in animals (similarity 0.84)
• Identical circumstances trigger and collapse arms races in animals and humans. (similarity 0.84)
• Human and animal arms races follow parallel evolutionary dynamics (similarity 0.84)
• Intense competition without duel structure does not drive weapon evolution. (similarity 0.83)

Broader Connections

• One-on-one duels favor weapon evolution while chaotic scrambles do not. #corroborates (0.85) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 245
• Balancing selection normally curbs weapon size until some lineages escape into runaway arms races #expands (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 22
• Specific ecological circumstances must align before weapon arms races begin #exemplifies (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 137
• Dominant weapons become obsolete when their intended fights never occur #qualifies (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 456
• Weapons innovations trigger arms races in ships just as in animals #expands (0.45) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 962
• Human and animal arms races follow parallel evolutionary dynamics #expands (0.40) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 463
• Human fortifications and artillery evolve via the same arms-race logic as animal weapons #expands (0.40) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 525