In a paper in Science from October, Jennifer Whitson and Adam Galinsky report that placing people in situations where they lack control increases the false perception of patterns because of a need to impose structure on even random events.
This study is very interesting because it helps us understand why we develop superstitions and the like, which are based on false pattern recognition. It does not, however, speculate on why some of those superstitions take hold and last (e.g., buildings without thirteenth floors) and some do not (e.g., my efforts to get my tee ball team to wear pink socks after a 3-4, 4RBI game and a laundry accident).
I, however, am not above some wild speculation. The defense of superstitions, quack medical treatments, etc. frequently goes like this: A medical
treatment works or it does not work. If it works, people who use the
treatment are more likely to live, people who don't are more likely to
die and the treatment keeps getting used. If it does not work, people
who use the treatment are more likely to die, people who don't are more
likely to live and the treatment stops getting used. That makes
intuitive sense. It sounds a lot like selection, and we like
selection.
The Chinese have been using acupuncture for thousands of years,
supposedly. It must be safe and effective. People have been eating a
Mediterranean diet for thousands of years. It must be good for you.
We've all heard these arguments before and probably made some of them
ourselves. Let's forget for a moment that acupuncture may not be
ancient or Chinese or that Italians only
started eating tomatoes in the last 300 years.
Seems intuitive, right? Chances are, however, that our intuition is just flat out wrong. Why? Evolutionary theory says we are wrong.
The principles of
evolutionary theory can be applied to any system that consists of
discrete, varying, replicating units. In fact, most of those
evolutionary principles were developed before we knew that genes were
made of DNA. In this sense, ideas are like genes. They are
relatively discrete. They have different versions. They can
replicate. A brief illustration of this point follows.
Ideas are discrete
Idea 1: What is your favorite ice cream flavor?
Idea 2: What is your favorite color?
Ideas have different varieties
Idea 1.1: I like mint chocolate chip.
Idea 1.2: I like vanilla.
Ideas can replicate
Person A: I can't decide if I prefer mint chocolate chip or vanilla.
Person B: I like mint chocolate chip.
Person A: B is right. Mint chocolate chip is better than vanilla.
So, maybe the superstitions that last are selected for? Often, when people (including
scientists) think evolution, they think selection, but they forget about the
three other forces that drive evolution: drift, mutation, and
recombination. Selection and drift are related, as they both act to reduce variation. We are going to be interested in the interplay between
selection and drift.
Drift is the effect of random
chance on populations. Because real
populations are not infinite, not all individual random effects are
balanced out by random effects in the opposite direction. In real
populations, random events affect outcomes. As the population size
decreases, drift becomes more important and selection becomes less
efficient (i.e., larger selective benefits are needed to overcome the
effects of drift). Eventually, drift could lead to the fixation
(everybody has the same version of the gene or idea) of a gene or idea
with no fitness benefit or, even, a negative fitness effect.
There is a range of fitness effects within which the gene or idea variant
acts like it has no effect on fitness, even if it has a positive or
negative fitness effect in individuals (expressed as the coefficient of
selection, which how much proportionally less fit one version is
compared to the more fit version). This range is dependent on the
effective population size (the number of randomly mating individuals
needed to explain the population genetics of a group) according to the
equation s=1/4Ne, where "s" is the selection coefficient and "Ne" is
the effective population size.
The absolute population size for
humans is approximately 6 billion. The genetic effective population
size is estimated at 10,000. That means that selection dominates for
selection coefficients larger than 0.000025 (2.5 excess deaths per
100,000 individuals). What is the effective population size for
ideas? With the advent of the internet, one might expect that the
effective population size for ideas would be large; but, most
information originally comes from wire services or text books. We can
make plausible arguments for large or small effective population sizes
for ideas.
Let's try an example to
estimate a limit to the effective population size for ideas. The
by-products of coal burning power plants are estimated (let's use a number I heard once) to kill 30,000
Americans (total population ~300 million) each year. Although 30,000
sounds like a lot, it is only 1 extra death per 10,000 people
(s=0.0001). When we rearrange our equation s=1/4Ne to Ne=1/4s,
we get an upper-bound for the effective population size for ideas of
2500 (it could be smaller). Is this number reasonable when compared to
an absolute population size of 300 million? It is a 5 order of
magnitude difference, but not all 300 million of us are freely
exchanging ideas with anyone and everyone else. The intellectual
equivalent of free sex with the entire population is reserved for a few
wire services, television channels, and text books. Maybe 2500 is
reasonable.
I wonder how small the effective population size for ideas was in the Europe that used blood
letting? Could we reasonably be talking about effective population
sizes for ideas of less than 100 people? That is fertile ground for
bad ideas. Dark Ages anyone?
