Evolution of the monkey crouch.

Evolution of the Monkey Crouch T. PFAU ET AL. (“MODERN RIDING STYLE IMPROVES HORSE RACING times,” Brevia, 17 July, p. 289) nicely document the effectiveness of the “monkey crouch” riding style on race times and horse-jockey biomechanics. This style produced measurable speed benefits to winning race times at the English Epsom Derby Stakes (1900–1910). The change in riding style across a decade of different jockeys prompts the question: How did the monkey crouch originate? Many authors credit two American jockeys—Willie Simms and Tod Sloan— with bringing this style to England in 1895 and 1897, respectively. However, English rider Harding Cox claimed to have adopted the monkey crouch still earlier. Cox even described how he developed the style and what benefits it conferred: “When hunting, I rode very short, and leant well forward in my seat. When racing, I found that by so doing I avoided, to a certain extent, wind pressure, which ... is very obvious to the rider. By accentuating this position, I discovered that my mount had the advantage of freer hind leverage” (original italics) (1). Measurements taken by Pfau et al. support Cox’s impressions. Did Cox intend to design his new riding position? Did he purposefully reposition himself on his horse after painstaking mathematical calculations? Did he record wind pressure scores or take biomechanical readings to assess his new riding style? Probably not. It is more likely that he merely proceeded by trial and error, much as did Olympic champion Dick Fosbury when he invented his famous high jumping “flop” (2). Inventive behavior is often attributed to creativity or to genius when a simpler explanation suffices. The origin of the monkey crouch perfectly fits the Law of Effect: Successful behavioral variations are retained and unsuccessful variations are not. This positively Darwinian process works for human inventions just as it does for earthly organisms—mechanically and without design or purpose.