Complexity Explorer Santa Few Institute

A term coined from the era before the first World War, representing a reinforcing (i.e. positive) feedback loop between two nations seeking to have the larger armed forces. The most well known arms race is the nuclear arms race of the Cold War.

In the modern era, the term has begun to describe competitions in which there is no definite goal beyond staying ahead of one's competitor. The term is often applied in biology, as in the description of the co-evolution of hosts and parasites or pathogen response to antibiotics.

An evolutionary arms race refers to the competition between two evolving populations to outperform each other. This is an analogy to a literal arms race such as the nuclear arms race between the Soviet Union and United States during the cold war. An example of this would be the rough-skinned newt (Taricha granulosa) evolving an increasingly strong toxin to protect itself from predation while the common garter snake (Thamnophis sirtalis) continues to evolve a resistance to the toxin.