Does any type of pain serve a
purpose? Many people say that acute
pain is an evolutionary adaptation
that warns the brain to take action
against tissue damage. As evidence
they cite people with a rare genetic
disorder that renders them unable to
perceive pain, called congenital
analgesia. Many people who suffer
from the condition die by the age of
25; however, most of their injuries
are not those that would cause a
normal person severe pain, such as
burns. Other sensory signals, like the
perception of heat, can also warn the
brain to take action against tissue
damage, so long as the person has
been taught that heat damages the
skin. Rather, these people often
severely damage their joints because
they do not feel the dull ache that
results from standing or sitting in one
position for too long. This dull ache
is what provokes normal people to
change position, thereby preventing
joint damage.