Generalists vs. Specialists (And the Specialist’s Dilemma)


Animal species reside on a scale with “generalist” on one end and “specialist” on the other. Specialists can live only in a narrow range of conditions: diet, climate, camouflage, etc. Generalists are able to survive a wide variety of conditions and changes in the environment: food, climate, predators, etc.

Specialists thrive when conditions are just right. They fulfill a niche and are very effective at competing with other organisms. They have good mechanisms for coping with “known” risks. But when the specific conditions change, they are much more likely to go extinct. Generalists respond much better to changes/uncertainty. These species usually survive for very long periods because they deal with unanticipated risks better. They have very coarse behavior: eat any food available, survive in many climates, use a simple mechanism to defend a wide range of predators, etc. But unlike specialists they don’t maximize their current environment, because they don’t fill a niche where they could be more successful. It’s tough being a generalist—there’s more competition.

An environment with more competition breeds more specialists. Rainforests have huge diversity and competition, and therefore many specialist species.

…This is what I call the Specialist’s Dilemma. The stronger your competitive position, the more vulnerable you are to eventually being disrupted and replaced.

Hrm. This reminds me of the (artificial) distinction between foxes and hedgehogs.

Among the fragments discovered of the Greek poet Archilochus is one that says ‘The fox knows many things, but the hedgehog knows one big thing.'

In the Hedgehog and the Fox, Isaiah Berlin mentions:

Scholars have differed about the correct interpretation of these dark works, which may mean no more than the fox, for all his cunning, is defeated by the hedgehog's one defence. But, taken figuratively, the words can be made to yield a sense in which they mark one of the deepest differences which divide writers and thinkers, and, it may be, human beings in general. For there exists a great chasm between those, on one side, who relate everything to a single central vision, one system, less or more coherent or articulate, in terms of which they understand, think and feel—a single, universal, organizing principle in terms of which alone all that they are and say has significance—and, on the other side, those who pursue many ends, often unrelated and even contradictory, connected, if at all, only in some de facto way, for some psychological or physiological cause, related by no moral or aesthetic principle.

Philip Tetlock, author of Expert Political Judgment: How Good Is It? How Can We Know?, researched whether foxes or hedgehogs are better able to make predictions. He concludes that we should employ serious skepticism about experts' ability to predict the future. Tetlock says “There's quite a range. Some experts are so out of touch with reality, they're borderline delusional. Other experts are only slightly out of touch. And a few experts are surprisingly nuanced and well-calibrated.” So what distinguishes the impressive from the out of touch? How they think. Tetlock dubbed his experts “foxes” and “hedgehogs.” And the data couldn't be more clear in terms of predictions, foxes beat hedgehogs.*

Berlin warns, “Of course, like all over-simple classifications of this type, the dichotomy becomes, if pressed, artificial, scholastic and ultimately absurd. But if it is not an aid to serious criticism, neither should it be rejected as being merely superficial or frivolous; like all distinctions which embody any degree of truth, it offers a point of view from which to look and compare, a starting-point for genuine investigation.”

Continue Reading Generalists vs. Specialists.

* There is a good discussion of Tetlock in Dan Gardner's book Future Babble (p25-27) see my review here