Complex decisions are best left
to your unconscious mind to work out, according
to a new study, and over-thinking a problem
could lead to expensive mistakes.
The research suggests the conscious mind should
be trusted only with simple decisions, such
as selecting a brand of oven glove. Sleeping
on a big decision, such as buying a car or house,
is more likely to produce a result people remain
happy with than consciously weighing up the
pros and cons of the problem, the researchers
Thinking hard about a complex decision that
rests on multiple factors appears to bamboozle
the conscious mind so that people only consider
a subset of information, which they weight inappropriately,
resulting in an unsatisfactory choice. In contrast,
the unconscious mind appears able to ponder
over all the information and produce a decision
that most people remain satisfied with
Ap Dijksterhuis at the University of Amsterdam
in the Netherlands, and colleagues recruited
80 people for a series of lab-based and "real-world"
tests. The participants were provided with information
and asked to make decisions about simple and
complex purchases, ranging from shampoos to
furniture to cars.
In one of the tests, half of the participants
were asked to ponder on the information they
were given and then decide which among similar
products to buy. The other half were shown the
information but then made to perform a series
of puzzles including anagrams and simple arithmetic.
At the end of the puzzle session, the participants
were asked to make a snap decision about the
"We found that when the choice was for something
simple, such as purchasing oven gloves or shampoo,
people made better decisions - ones that they
remained happy with - if they consciously deliberated
over the information," says Dijksterhuis.
"But once the decision was more complex such
as for a house, too much thinking about it led
people to make the wrong choice. Whereas, if
their conscious mind was fully occupied on solving
puzzles, their unconscious could freely consider
all the information and they reached better
However, the unconscious mind appears to need
some instruction. "It was only when people were
told before the puzzles that they would need
to reach a decision that they were able to come
up with the right one," Dijksterhuis stated.
If they were told that none of what they had
been shown was important before being given
the puzzles, they failed to make satisfactory
"At some point in our evolution, we started
to make decisions consciously, and we're not
very good at it. We should learn to let our
unconscious handle the complicated things,"
Journal reference: Science (vol 311,