Mind Hacks™: Tips & Tools for Using Your Brain (36 page)

Our sense of logic is much better when applied to social situations than used in
abstract scenarios.

Each of the cards in
Figure 7-1
has a
letter on one side and a number on the reverse. If I told you there was a rule stating
that a card with a vowel on one side must have an even number on the reverse, which of
these cards would you need to turn over to prove or disprove this rule?

Many people turn over A and 2 — but that’s not quite right. While turning over A will
tell you whether “one side” of the rule is true (
if
vowel,
then
even number), turning over 2 won’t tell you any more. It
doesn’t matter whether 2 has a K or an A on its reverse — the rules doesn’t specify either
being true. Along with A, the other card you need to turn over is 7. If 7 has an
A
on its reverse, then the rule is disproved no matter what the A
has on its reverse. You
need
to turn over A and 7.

Figure 7-1. Each card has a letter on one side and a number on the reverse

Very few people solve this riddle on the first try. It shows that humans do not
possess an innate set of abstract logic rules. Yet somehow we manage to get by without
those rules. Try this similar puzzle, in
Figure 7-2
.

Figure 7-2. Four people sit at a bar drinking beer or cola, the cards show age on one side and
beverage on the other — who’s breaking the rules?

Say there’s a rule that you must be 21 or over to drink beer. Whose drinks and ages
would you need to check to see if this bar is flouting the rules?

By simply swapping drinks and ages for cards A, K, 2, and 7, it’s obvious this time
around that there’s no point checking what the 21 year old (think 2 card) is drinking — it
wouldn’t make any difference to the rule if she were drinking cola or beer, whereas the 16
year old’s (think 7 card) drink is of much more interest.

Why are logic problems so much easier when they’re expressed as real-life
situations rather than in abstract terms? One early hypothesis called
memory
cuing
proposed that we solve logic problems by drawing on personal
experience, without using any deductive reasoning. We’ve all experienced the problems of
drinking ages enough times that we don’t even have to think about who should be drinking
what, unlike playing with letter and number cards.

Despite the substantial evidence behind memory cuing,
^2
,
3
many
scientists believe that in practice we use more than just experience — that there is in fact
some thinking involved. Instead, researchers such as Cheng and Holyoak
⁴
think that, while we might not be so good at pure logic, we’re excellent at
the logic we need in real life — rules, permissions, and obligations. This type of
logic —
deontic logic —
is what helps us solve everyday logic problems,
by developing what they call “pragmatic reasoning schemas.” Therefore, it shouldn’t be
surprising that our ability with logic is domain-specific, that is, limited to analyzing
the complex web of permissions and obligations we encounter in life.

It’s been suggested by Cosmides,
⁵
a leading light of evolutionary psychology (the study of how evolution may
have shaped the way we think
⁶
), that the reason we seem to possess domain-specific logic is because it’s
been selected for by evolution over countless generations. Cosmides argues that the really
important parts of Cheng and Holyoak’s pragmatic reasoning schemas are those about people.
In other words, we are all born with the mental logic required to understand the costs,
benefits, and social contracts involved in dealing with other people. It’s a compelling
argument, since the ability to make beneficial deals is a valuable survival trait.
However, Cosmides’ theory can’t be the whole story, since we have no problem in solving
many logic problems that have nothing to do with costs, benefits, or indeed other people
at all. For example, the rule “If you’re going to clean up spilt blood, then you need to
wear rubber gloves” is easily understood and applied even though it doesn’t concern other
people.

Before resigning yourself to a life without logic, it’s worth remembering that along
with the countless other skills that we aren’t born with, we can understand logic the hard
way — by learning it. Even if you don’t, you can still console yourself with the knowledge
that you’re as good as any philosopher in the everyday logic that
really
matters.

— Adrian Hon

Many of the unpleasant phenomena associated with injury and infection are in fact
produced by the brain to protect the body. Medical assistance shifts the burden of
protection from self to other, which allows the brain to reduce its self-imposed
unpleasantness.

It’s hard to invent a placebo and try it on yourself, because the effect relies
crucially on the sincerely held belief that it will work. Several experiments have shown
that pure placebos such as fake ultrasound produce no pain relief when they are
self-administered. So unless you can fool yourself that other people are caring for you
when they are not, your experiments with placebos will have to involve other
people.

Moreover, you will also probably have to lie. The placebo effect depends not just on
other people, but also on the belief that those people are providing bona fide medical
assistance. If you don’t believe that the assistance provided by those around you is going
to help you recover, you won’t experience a placebo effect.

Sometimes a placebo effect seems to be triggered despite the absence of other people
and the absence of deception. If you have ever felt better after taking a homeopathic
remedy, for example, or after applying dock leaves to the pain caused by a stinging
nettle, that was almost certainly a placebo effect, because it has been scientifically
proven that such treatments are completely bogus. The essential factor, however, must
still be present — a belief that this kind of treatment will help. Once you discover the
truth about such bogus treatments, therefore, they cease to be capable of producing
placebo effects.

Because it is hard (some might say impossible) to deceive yourself into believing
something that you know to be false, deception is important for most placebo experiments.
This plays a central role in many psychological experiments, and raises serious ethical
problems. In universities and other research environments, an ethics committee must, quite
rightly, approve experiments before they are allowed to proceed. It is therefore advisable
to conduct the following experiment in the privacy of your own home, where ethics
committees have no jurisdiction.

First, take an old medicine bottle and clean it thoroughly. Then fill it with a
solution of tap water, sugar, and food coloring. The next time someone you know gets a
headache or is stung by a stinging nettle, tell her that you have a special remedy that
will help. If she asks what it is, tell her that it is a special solution of water and
sugar and food coloring, and say that you have read somewhere (in this book) that this
will help her feel better (that way, you won’t even be lying!). Give her the colored water
and ask her to drink a teaspoonful (if she has a headache) or to rub a small amount onto
the affected area (if she has been stung by a nettle). See if it helps her feel
better.

It will, if she believes it will —
and
if there’s nothing
really wrong with her (be careful here; don’t delay medical treatment for someone who is
hurt because you want to see if you can placebo-cure her).

Studies have shown that for some people in some situations the placebo effect can be
as strong as morphine. In one particularly striking study,
¹
patients who had undergone tooth extraction were treated with ultrasound to
investigate whether this would reduce the postoperative pain. Unknown to both doctors and
patients, however, the experimenters had fiddled with the machine, and half the patients
never received the ultrasound. Since ultrasound consists of sound waves of very high
frequency — so high, in fact, that they are inaudible to the human ear — there was no way for
either the doctors or the patients to tell whether the machine was emitting sound waves;
the test was truly double-blind. After their jaws were massaged with the ultrasound
applicator, the patients were asked to indicate their level of pain on a line with one end
labeled “no pain” and the other “unbearable pain.” Compared with a group of patients who
were untreated, all those treated with the ultrasound machine reported a significant
reduction in pain. Surprisingly, however, it didn’t seem to matter whether the machine had
been switched on or not. Those who had been massaged with the machine while it was turned
off showed the same level of pain reduction as those who had received the proper
treatment. In fact, when the ultrasound machine was turned up high, it actually gave less
pain relief than when it was switched off.

Other studies have shown that placebo medicines are more effective if delivered in
person by doctors and that it helps more if the doctors are wearing white coats. Red pills
give a bigger placebo effect than white pills, and placebo injections are more powerful
still.

Nobody knows for sure yet how the placebo effect works, but one theory is that the
brain is very sensitive to the presence of social support during the process of recovery
from injury and infection. The various components of the acute phase response are all
designed to promote recovery and prevent further injury while recovery is taking place.
Pain, for example, makes you guard the wounded area. But these measures also have costs;
high levels of pain, for example, can actually lengthen the healing process. The brain
makes a trade-off between the risks of further damage to the injured area and the delay to
the healing process. The presence of social support during recovery shifts the balance
between these competing risks because some of the burden of preventing further damage is
transferred from the sick person to those around them. The sick person can therefore
reduce his own costly
self-protective measures, such as pain, and allow the healing process to
progress more rapidly.

Another suggestion is that the placebo effect works by means of conditioning (see also
Make the Caffeine Habit Taste Good
). Conditioning is a very general
kind of learning process in which one stimulus is substituted for another. The classic
example is Pavlov’s dogs, which learned to salivate on hearing a bell after Pavlov had
trained them to associate the sound of the bell with the arrival of food. In technical
terms, an
unconditioned stimulus
(the sight of the meat), which leads
naturally to a certain
unconditioned response
(salivating at the
sight of the meat), is repeatedly paired with a
conditioned stimulus
(the sound of the bell). Eventually, the dogs learn the
conditioned
response
of salivating at the sound of the bell. Pavlov’s students showed
that immune responses can also be conditioned, and others have gone on to suggest that
this is what lies behind the placebo response. The unconditioned stimulus is a real drug
or some other medical treatment that works even if you have never tried it before and
don’t believe in it. The unconditioned response is the improvement you feel after
receiving the treatment. The conditioned stimuli are all the things that are repeatedly
paired with the treatment — the size, shape, and color of the pill, for example. If you then
take a pill that has the same size, shape, and color as the real one, but which lacks the
active ingredient, you may still experience some improvement because your immune system
has been conditioned to respond to such stimuli.

Placebos won’t cure the vast majority of medical conditions. It is much easier and
quicker to list the things that placebos
can
influence — pain,
swelling, stomach ulcers, some skin conditions, low mood, and anxiety — than the things they
don’t. Everything else is probably not placebo-responsive. That said, placebos are able to
help in the management of nearly all illnesses because nearly all illnesses involve pain,
low mood, and/or anxiety.

— Dylan Evans