How should we explain the origins of novel behaviors?
A celebrated case of human behavioral invention lends credence to our view. Dick Fosbury revolutionized the high jump with a world-record bound of 7 feet, 4 ¼ inches, which earned him a gold medal at the 1968 Olympics. Some might suspect that his innovation—the so-called Fosbury Flop—was designed with purpose and foresight in a single creative moment. In fact, it unfolded over considerable time, beginning in high school when Fosbury used the outmoded “scissors” jump. Urged by his coach to adopt the more sophisticated “straddle,” his lanky body failed to comply with his coach’s wishes. When Fosbury reverted to the “scissors,” he began to lift his hips to reach higher altitude, thereby forcing back his head and shoulders. In this way, the flop evolved, not from design, but from a protracted trial-and-error process that combined repeated effort with the biomechanics of Fosbury’s gangly physique. Here is how Fosbury himself described this process: “I began to lift my hips up and my shoulders went back in reaction to that. At the end of the competition, I had improved my best by 6?, from 5′ 4? to 5′ 10? and even placed third! The next two years in high school, with my curved approach, I began to lead with my shoulder and eventually was going over head first like today’s Floppers.”
Another example of human behavioral invention from the sporting world—this one from thoroughbred racing—further supports our view. A recent report in Science carefully explained how the monkey crouch—the currently dominant racing style, in which the jockey rides poised above the saddle leaning forward—promotes faster racing times. At the expense of a much more strenuous ride for the jockey than the earlier, upright style, the monkey crouch confers measurable biomechanical benefits for the horse. No one has yet suggested that the monkey crouch was designed with purpose and foresight to maximize biomechanical efficiency. So how did it arise?
Some authors have credited two American jockeys with bringing the monkey crouch to England in the late 1800s. An English rider, Harding Cox, may actually have adopted this riding style a bit earlier. Critical to our present considerations, Cox suggested in his memoir the possible benefits that the monkey crouch 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. Perhaps that is why I managed to win on animals that had been looked upon as ‘impossibles,’ ‘back numbers,’ rogues and jades.”
Although the authors of the Science report emphasize the biomechanical benefit to the horse of having the jockey rise from the saddle, and they deemphasize the role of decreased wind resistance, Cox’s account provides a key insight into this innovation’s true origins. Specifically, decreased wind resistance may have initially encouraged Cox’s forward adjustment, which allowed his later accentuation of the posture into the fully realized monkey crouch. Like a scaffold that provides a temporary structure for the construction of a building, Cox’s response to wind pressure may have scaffolded his behavioral transition to a novel riding style—one that transformed modern thoroughbred racing.
Inventive behaviors are commonly attributed to creativity, insight or genius, but a far simpler explanation may do. For the Fosbury Flop and the monkey crouch, an elegant and plausible way to understand the origins of novel behaviors can be found in the law of effect, which emerged a century ago from the animal-behavior studies of psychologist Edward Thorndike. The law of effect states that successful behavioral variations are retained and unsuccessful variations are not. Importantly, this positively Darwinian process exists entirely outside the realm of purpose or foresight. If everything in nature is the result of fixed laws, as Darwin himself proposed, then would he not also have marveled at the explanatory power of the law of effect—which was not discovered until several decades after his death—and its compelling parallels with natural selection?
Our prime point here is the importance of the search for origins. Darwin has taught us that the search for the origin of species reveals the action of natural mechanisms that do not require guidance from a creative, intelligent designer. Similarly, Petroski has taught us to look beyond the romance of the iconoclastic inventor and the drama of the creative moment to appreciate the real origins of human artifacts. Petroski’s insight should free evolutionists from their continuing dispute with creationists over where to draw the line between things that really are designed and things that only appear to be designed. Belief in the existence of that false line only serves to obscure the powerful selectionist processes that are at work in producing so many of the world’s creations—both organic and synthetic.
Beyond the concerns of Darwin and Petroski, we see additional fertile ground for reshaping how we think about the origins of behavioral innovations. We have focused here on the Fosbury Flop and the monkey crouch, but we could also have discussed the role of serendipity in scientific discovery or the developmental path by which each of us learns to crawl, walk and run. From our first days of life, we are all inventors who discover by trial and error how our growing bodies work and move. As with organic evolution, the development of behavior is indeed a creative process, but it is one that unfolds without purposeful design.