The Handicap Principle

Cover via Amazon

If natural selection functions the way Darwin postulated: with each animal’s feature evolving strictly for utilitarian reasons, how can one explain the waste one sees in nature all the time?  The peacock’s tail hinders movement; babblers spend precious time foraging food for other babblers; and, when it sees a wolf, a gazelle often does not run but spends precious time rising and thumping the ground with its hooves.  If the utilitarian selection Darwin posited was the only process at work, then it is hard to account for such wasteful behavior. 

Amotz and Avishag Zahavi explain this waste by postulating that this is how animals, including humans, show off their quality to potential mates, other members of their species, and predators alike.  Their basic hypothesis (which they prove by example after example in this beautifully written book) is that, in order to recreate, individuals must reliably signal their fitness.  A signal can only be reliable if the individual undertakes a handicap (accepts waste) such as not running away when seeing a predator approach.  And so they conclude that while efficiency is the rule of normal (or Darwin’s utilitarian selection), Darwin’s selection is complemented by the seemingly wasteful “signal selection”.  The two selections alternate with and complement each other.

They illustrate their hypothesis (called the handicap principle) through a series of examples from the natural world.  As a result, the world they paint is one in which everyone—from the single cell organism to humans is constantly communicating with everyone else.  Prey communicates with predators and predators with prey; potential mates display their quality (the peacock’s large tail mentioned earlier is a good example—and one that appears on the cover of the book); and rivals communicate by approaching one another—a human male for example, approaches his (potential) adversary with “a straight back, chest thrown out, shoulders back, chin up” (Zahavi, 17).  The Zahavis point out that by approaching a rival in this manner, the human male leaves himself open to attack as his most vulnerable body parts are clearly displayed to his adversary.  Nonetheless, they postulate that this posture evolved precisely because it is wasteful.  By showing off in this manner, the male is saying (in essence) I can beat you even if you do get a good punch in first.

And here I must come to my fair warning.  To the Zahavis, human beings are an integral part of the natural world and they observe them just as they observe babblers or monkeys.  The results will cause some to profoundly disagree for ideological reasons (as when the Zahavis postulate that “humans, like other animals, resolve most conflicts by communicating—which often includes the exchange of threats”) or for religious reasons as when the Zahavis use the people around them (which quite often are people in the Holy Land) to prove their point.  Indeed, at one point they cite the Bible as illustration.  So, if you are offended by the idea that humans are no better (but also no worse) than other animals or if you can’t accept the idea that humans not only evolved like other animals but that they are continuing to do so in the Holy Land, this book is probably not for you.

On the other hand, if you are interested in evolutionary biology, human and animal behavior and have been looking for a beautifully written and wonderfully illustrated book on the subject this is a great book.  The writing flows, the authors make their point by using compelling and convincing examples (rather than graphs and equations) and the illustrations are fantastic.  Best of all, after reading this book, you may see your own actions (or signals) in a brand new light. 

I simply cannot recommend this book enough. 

Related article: The Selfish Altruist