《经济学家》杂志上最近有一篇文章”Mind
games“，讨论了”神经经济学”(neuroeconomics)，一门通过对神经科学的研究来发现人的大脑如何进行经济决策。
文章说传统经济学认为对于是进行储蓄还是投资这样的决策，人被假设成完全考虑自身利益的冷酷的计算器（即理性人）。但是近几年来心理学的研究使得许多经济
学家相信这个假设并不一定成立。如今一个新兴的领域，神经经济学试图通过解读人类的大脑来阐述人的经济行为的理性与感性的实质，以期预测社会经济。文章全
文如下：
Can studying the
human brain revolutionise economics?
ALTHOUGH
Plato compared the human soul to a chariot pulled by the two horses of
reason and emotion, modern economics has mostly been a one-horse show.
It has been obsessed with reason. In decisions from how much to produce
to whether to save and invest, humans have been assumed to be coolly
rational calculators of their own self-interest. Over the past few
years, however, evidence from psychology has persuaded many economists
that reason does not always have its way. Now, judging from a series of
presentations at the American Economic Association meetings in
Philadelphia last weekend, a burgeoning new field dubbed
“neuroeconomics” seems poised to provide fresh insights on how the two
horses together produce economic behaviour.
The current
bout of research is made possible by the arrival of new technologies
such as functional magnetic-resonance imaging, which allows
second-by-second observation of brain activity. At several American
universities, economists and their collaborators in the neurosciences
have been placing human subjects in such brain scanners and asking them
to perform a variety of economic tasks and games.
For example,
the idea that humans compute the “expected value” of future events is
central to many economic models. Whether people will invest in shares
or buy insurance depends on how they estimate the odds of future events
weighted by the gains and losses in each case. Your pension, for
example, might have a very low expected value if there is a large
probability that bonds and shares will plunge just before you
retire.
Brian
Knutson, of Stanford University, carried out one recent brain-scan
experiment to understand how humans compute such things. Subjects were
asked to perform a task, in this case pressing a button during a short
interval in which a certain shape was flashed on to a screen. In some
trials, the subjects could win up to $5 if successful, while in others
they would have to defend against a $5 loss. Before presenting the
target, the researchers signalled to subjects which kind of trial they
were in.
Brain
activity in certain neural systems seemed to reveal a strong
correlation with the amount of money at stake. Moreover, the prospects
of gains and losses activated different parts of the brain. Traditional
economists had long thought—or assumed—that the prospect of a $1,000
gain could compensate you for an equally likely loss of the same size.
In subsequent trials, subjects were given another signal: one that
provided an estimate of the odds of success. That allowed the
researchers to identify the regions of the brain used for recognising
an amount of money and for estimating the probability of winning (or
losing) it. Having identified these regions, the hope is that future
work can measure how the brain performs in situations such as share
selection, gambling or deciding to participate in a pension
scheme.
David
Laibson, an economist at Harvard University, thinks that such
experiments underscore the big role that expectations play in a
person's well-being. Economists have usually assumed that people's
well-being, or “utility”, depends on their level of consumption, but it
might be that changes in consumption, especially unexpected downward
ones, as in these experiments, can be especially
unpleasant.
Mr Laibson's
own work tries to solve a different riddle: why people seem to apply
vastly different discount rates to immediate and short-term rewards
compared with rewards occurring well into the future. People tend much
to prefer, say, $100 now to $115 next week, but they are indifferent
between $100 a year from now and $115 in a year and a week. In one
recent experiment, noted in our science section on October 30th, Mr
Laibson and others found that the brain's response to short-term riches
(in this case, gift certificates of $15 or $20) occurs largely in the
limbic system, a region that governs emotion. By contrast, the prospect
of rewards farther into the future triggers the prefrontal cortex,
which is often associated with reason and calculation. Thus, choosing
immediate economic gratification, by spending excessively on credit
cards or not saving enough even though you “know better”, could be a
sign that the limbic system is in charge. Government policies, such as
forced savings or “cooling off” periods for buying property or cars,
may be one remedy.
And then
there is trust and deception. Colin Camerer, of the California
Institute of Technology, has conducted experiments in which
brain-scanned participants play strategic games with anonymous
partners. In these, a subject chooses his own actions and also tries to
anticipate the choices of the other player. When players are doing the
best that they can to “win” the game by anticipating their opponents'
moves, their brains tend to show a high degree of co-ordination between
the “thinking” and the “feeling” regions. Economic equilibrium, by this
measure, is an identifiable “state of
mind”.
Some
neuroeconomists claim that such brain-scanning experiments are the
start of a revolution in economics. No longer will economists rely on
crude statistical models of how people behave in response to a policy
change, such as an interest-rate rise or a tax increase. Instead, they
will be able to peer directly into the brain to predict behaviour.
One day,
perhaps; but much work remains. Identifying the parts of the brain that
control economic actions is one thing. Harder tasks include determining
how neural systems work together to create behaviour, and how wide is
the variation in brain patterns between different people. Then there
are age-old questions of free will: is your failure to save for old age
simply a lifestyle choice, or is it down to faulty brain circuits?
Neuroeconomics is already providing fascinating conclusions. But
Plato's chariot will remain an alluring explanation for a while
yet.
又，维基百科对于神经经济学的解
释是 Neuroeconomics
combines neuroscience, economics, and psychology to study how we make
choices. It looks at the role of the brain when you evaluate decisions,
categorize risks and rewards, and interact with other people.