A bird in the hand: what chimps are teaching us about our value biases

We’ve all heard the old axiom, “a bird in the hand is worth two in the bush.” That means, of course, that possessing something valuable makes its value appear greater than another, ostensibly more valuable thing we don’t possess. In boffin terms, this is called “the endowment effect,” and even two equally-valuable items can seem to have different apparent value depending on whether you possess one or the other.

But does that make any logical sense? Obviously, two shovels of the same make and model would logically seem to have the same value. Value is nevertheless a question of judgement, which economics normally regards as subjective and fluid: a shovel is of no value to a person who needs a hammer. A thing cannot have value without the arbitrary judgment of a human.

New research into chimp behavior may change that way of thinking. Researchers from Vanderbilt University have discovered that the same behavior can be observed in chimpanzee preferences. When a chimp possesses one object, it will disregard a similar object as though it was of lesser value, particularly when the object in question is a tool that can be used to obtain food.

Drawing on prior theoretical work by Jones on the evolution of seemingly irrational behaviors, Brosnan and Jones found consistency between chimpanzees and humans with respect to the existence of the endowment effect and, more importantly, showed that variations in the prevalence of the effect could be predicted.

And interestingly, this bias disappears once there’s no food to be gained. In other words, not only is the value of the object dependent upon possession, but also on the usefulness of the tool for other gains.

Of course, the “bird in the hand” expression denotes what we as humans think of as common sense. And yes: possessing a useful tool means not having to incur the risk associated with getting the other, identical object. But it now appears that this decision making is rooted in some deeper evolutionary decision making that is shared, at minimum, with at least one other primate species.

By Tommy Belknap

Owner, developer, editor of DragonFlyEye.Net, Tom Belknap is also a freelance journalist for The 585 lifestyle magazine. He lives in the Rochester area with his wife and son.