The Believing Brain - Michael Shermer [149]
The Middle Land of Belief
Now that we have drilled deep into the brain to examine the cognitive biases of belief, let us pull back for a broader view of what I call the Middle Land of belief.
Imagine these two series of twenty-five heads (H) and tails (T) coin flips and guess which series best represents randomness:
THTHTHTHTHTHTHTHTHTHTHTHT
HHHTTHTTHTHHHHTTHHTTTTTTH
Most people would say that the first series of alternative heads and tails looks the most random, whereas, in fact, both computer simulations and actual coin-flipping experiments generate something much more like the second series (try it yourself). When subjects are asked to imagine flipping a coin and are then instructed to write down the sequence of outcomes, their guesses are highly nonrandom. That is, their string of Ts and Hs more closely resembles the predictable first string above and not the less predictable and more (but not perfectly) random second string.
This fact goes a long way toward explaining the apparent nonrandom guessing in ESP experiments that paranormal researchers claim as evidence for psychic power. In fact, in their analysis of ESP research over the past century, Peter Brugger and Kirsten Taylor have redefined ESP as effect of subjective probability, noting that scientists have now conclusively demonstrated what typically happens in research in which one subject tries to determine or anticipate the thoughts or actions of a second subject using paranormal means. When the second subject is instructed to randomly perform some task (such as raising or lowering an arm), the sequence is not going to be random. Over time the second subject will develop a predictable pattern that the first subject will unconsciously learn.31 This effect is called implicit sequence learning, and it has plagued paranormal research for over a century as researchers continue to fail to control for it. As the mathematician Robert Coveyou once quipped: “Random number generation is too important to be left to chance.”32
The reason that our folk intuitions so often get it wrong is that we evolved in what the evolutionary biologist Richard Dawkins calls Middle World—a land midway between short and long, small and large, slow and fast, young and old. Out of alliterative preference, I call it Middle Land. In the Middle Land of space, our senses evolved for perceiving objects of middling size—between, say, grains of sand and mountain ranges. We are not equipped to perceive atoms and germs, on one end of the scale, or galaxies and expanding universes, on the other end. In the Middle Land of speed, we can detect objects moving at a walking or running pace, but the glacially slow movement of continents (and glaciers) and the bogglingly fast speed of light are literally imperceptible. Our Middle Land time scales range from the psychological “now” of three seconds in duration to the few decades of a human lifetime, far too short to witness evolution, continental drift, or long-term environmental changes. Our Middle Land folk numeracy leads us to pay attention to and remember short-term trends, meaningful coincidences, and personal anecdotes.
Additional random processes and our folk numeracy about them abound. Hollywood studio executives often fire successful producers after a short run of box-office bombs, only to watch the subsequent films under production during the producer’s reign become blockbusters. Athletes who appear on Sports Illustrated’s cover typically experience career downturns, not because of a superstitious jinx but because of the “regression to the mean.” The exemplary performance that landed them on the cover in the first place is a low-probability event that is difficult to repeat, and thus they “regress” back to their normal performance levels.
Extraordinary events do not always require extraordinary causes. Given enough time