9

Further evidence against the Cartesian
theory was provided by Henry Knowles
Beecher (1904–1976), a World War II anesthesiologist.
Beecher was surprised to find
that 75 percent of men wounded in battle
did not ask for morphine and declined it
when offered, seeming to feel very little
pain, whereas civilians in peace time with
much less serious injuries seemed to feel
much greater pain. He concluded that the
wounded soldiers were so relieved not to
have been killed or suffered greater injuries
that they experienced their pain as minor;
the civilians were not expecting to be
injured at all and therefore felt their pain
more acutely. Beecher’s research implied
that the brain must play an active role in the perception of pain, a situation accounted for in gate
control theory by the brain sending its own signals down the spinal cord to push the gate shut.
These signals, discovered in 1975, are endorphins, chemicals produced in your body when you
exercise strenuously or do something pleasurable, which relieve pain and provide a sense of
well-being. They are very similar to opiates in chemical composition and effect (“endorphin” is an
abbreviation of “endogenous [internal] morphine”).