The Art of Thinking Clearly: Better Thinking, Better Decisions

See also Déformation Professionnelle (ch. 92); Omission Bias (ch. 44)

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66
WHY YOU ARE A SLAVE TO YOUR EMOTIONS
Affect Heuristic
What do you think of genetically modified wheat? It’s a complex issue. You don’t
want to answer too hastily. A rational approach would be to consider the
controversial technology’s pros and cons separately. Write down the possible
benefits, weight them in terms of importance, and then multiply them by the
probability that they will occur. Doing so, you get a list of expected values. Next,
do the same with the cons. List all the disadvantages, estimate their potential
damage and multiply them by the likelihood of them happening. The positive sum
minus the negative sum equals the net expected value. If it is above zero, you are
in favour of genetically modified wheat. If the sum is below zero, you are against
it. More than likely you have already heard of this approach. It is called ‘expected
value’, and it features in most literature on decision theory. But just as probable is
that you’ve never bothered to carry out such an evaluation. And without a doubt,
none of the professors who wrote the textbooks turned to this method to select
their spouses.
Truth be told, no one uses this method to make decisions. First of all, we lack
enough imagination to list all the possible pros and cons. We are limited by what
springs to mind; we can only conjure up what we have seen in our modest
experience. It is hard to imagine a storm of the century if you’re only 30 years old.
Second, calculating small probabilities is impossible because we do not have
enough data on rare events. The smaller the probability, the fewer data points we
have and the higher the error rate on the exact probability – a vicious effect. Third,
our brain is not built for such calculations. They require time and effort – not our
preferred state. In our evolutionary past, whoever thought too long and hard
vanished inside a predator’s jaws. We are the descendants of quick decision-
makers, and we rely on mental shortcuts called heuristics.
One of the most popular is the 
affect heuristic
. An affect is a momentary
judgement: something you like or dislike. The word ‘gunfire’ triggers a negative
effect. The word ‘luxury’ produces a positive one. This automatic, one-
dimensional impulse prevents you from considering risks and benefits to be

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independent variables, which indeed they are. Instead, the 
affect heuristic
puts
risks and benefits on the same sensory thread.
Your emotional reactions to issues such as nuclear power, organic vegetables,
private schools or motorbikes determine how you assess their risks and benefits.
If you like something, you believe that the risks are smaller and the benefits
greater than they actually are. If you don’t like something, the opposite is true.
Risks and benefits appear to be dependent. Of course, in reality, they are not.
Even more impressive, suppose you own a Harley-Davidson. If you come
across a study that states that driving one is riskier than previously thought, you
will subconsciously tweak how you rate the benefits, deeming the experience ‘an
even greater sense of freedom’.
But how does an affect – the initial, spontaneous emotion – come to be?
Researchers at the University of Michigan flashed either of three images for less
than one hundredth of a second in front of participants: a smiling face, an angry
face or a neutral figure. The subjects then had to indicate whether they liked a
randomly selected Chinese character or not (the participants didn’t speak
Chinese). Most preferred symbols that immediately followed the smiling face.
Seemingly insignificant factors influence our emotions. Here is another example
where an insignificant factor plays a role. Researchers Hirschleifer and Shumway
tested the relationship between the amount of morning sun and daily market
performance in 26 major stock exchanges between 1982 and 1997. They found a
correlation that reads much like a farmer’s adage: if the sun is shining in the
morning, the stock market will rise during the day. Not always, but often. Who
would have thought that sunshine could move billions? The morning sun
obviously has the same effect as a smiley face.
Whether we like it or not, we are puppets of our emotions. We make complex
decisions by consulting our feelings, not our thoughts. Against our best intentions,
we substitute the question, ‘What do I think about this?’ with ‘How do I feel about
this?’ So, smile! Your future depends on it.