County Kerry, Ireland
We're sitting around a peat fire, while rain batters the windows of
the cottage and a howling gale blows in from the Atlantic. Five of
us are here for a workshop on the placebo effect, Anne Harrington
(historian of science), Howard Fields (neurobiologist), Dan Moerman
(anthropologist), Fabrizio Benedetti (neurphysiologist), myself (psychologist).
It's the latest in as series of interdisciplinary workshops under
the auspices of the Harvard Mind Brain Behaviour Initiative. We've
set ourselves the goal of writing a joint paper by the end of the
summer "How to think well about the placebo effect". We've decided
to organise it around Niko Tinbergen's four "Whys?": proximate causation,
developmental history, biological function, evolutionary history.
own interest is especially in the question of evolutionary design.
When a person recovers from illness as a result of placebo treatment,
it must of course be his own healing system that is doing the job.
Placebo cure is self-cure. But if the capacity for self-cure
is latent, then why is it not used immediately? If a person can get
better by his own efforts, why doesn't he just get on with it as soon
as he gets sickwithout having to wait, as it were, for outside
permission? Why should the mind be allowed to influence the
body in this waywhen the net result is, if anything,
to put a brake on healing?
The paradox can, I think, be resolved by considering the placebo effect
in a broader biological context.
Long before medicines or doctors came on the scene, we should assume
the ancestors of human beings had already developed a fine capacity
for looking after their own health: by mounting defences such as pain
and fever, by actively attacking infections, by repairing bone and
tissue damage, by indulging in sickness behaviours, and so on. However
none of these measures would ever have been free of cost (immune resources
are expensive, pain is debilitating, acting-sick is time-wasting,
etc.). So it must always have been essential to have some kind of
internal "health management system" in place, to ensure that the way
the body responded to any particular threat was nearly optimal.
for example, it would have been best for a sick person to get well
as rapidly as possible, throwing off defences such as pain and mounting
a full-scale immune response; but at other times it might have been
more prudent to remain unwell and out of action and to conserve resources
for later use. As a general rule (and of crucial importance for the
story of placebos): the brighter the prospects for a rapid recovery,
the less to be gained from playing safe and remaining sick.
But this must have meant that the health management system would have
needed to take account, so far as possible, of any intelligence available
to the sick person about what the future held. Relevant information
would have included the nature of the threat, the costs of the defensive
measure, the prospects for spontaneous remission, evidence of how
other people were faring, the presence of social support, and so on.
The mind therefore must have had to become an adjunct to the healing
systemprecisely so as to gather this intelligence.
In the past all kinds of environmental information would have been
be brought to bear. And no doubt they still are. But today, the medicalisation
of sickness has changed the picture. For it means nowadays that there
will often be a novel and even overriding piece of information to
take into account. People have learnedtheir culture has taught
themthat nothing is a better predictor of how things will turn
out when they are sick (whether the pain will ease, whether the infection
will abate, whether they will be nursed back to health . . ) than
the presence of doctors, medicines, and so on.
Yet human beings remain tied to their evolutionary heritage. And so,
today, the very prospect of medical attentionthe patient's belief
in itworks its magic for the simple reason, stemming from the
general rule above, that for most of human history, once a sick person
has had cause to think that he will soon be safe and well,
he has had just the excuse he needs to bring on his own recovery as
fast as possible.
Benedetti, Nicholas Humphrey, Anne Harrington, Howard Fields, Dan
this is the story I've been pushing! Are my colleagues convinced?
It's such a different way of thinking for themespecially the
two neuroscientiststhat I'm afraid they haven't yet taken it
Planck said "A new scientific truth does not triumph by convincing
its opponents and making them see the light, but rather because its
opponents eventually die, and a new generation grows up that is familiar
with it." I like my friends in this group much too much to hope that
this is true.