Yet the same basic concept can be discerned in the very first essays on the
subject. "It requires no small amount of physical courage to stand up to a
batter's plate," wrote Elmer Berry in 1927. "(But) there is also often a
fear of another kind which must be overcome … The batter fears he will be
'shown up,' made to look 'bad' before the crowd."

Why then has sport - the very definition of a competitive business - taken so
long to accept the value of psychology? The explanation must lie in the
ineffable mystery of the brain - a murky grey morass that comes without an
operating manual.

Every truly outstanding sportsperson knows that what makes him or her
different, superior to the crowd, lies in the brain as much as the body. But
how many want to go rooting around for the mechanisms underpinning their
success? Mess with the mind, and it's not like spraining your ankle. There
are no anatomical diagrams showing how to repair the damage.

The same goes for those bold enough to seek individual help. They tend to keep
such consultations secret, for once you have admitted to a psychological
weakness, it is impossible to prove that you have conquered it.

But something has changed here: we may not have X-rays of the brain
that can define thought patterns as clearly as a broken bone, but we do have
CT scans and a growing understanding of neuroscience. Even if it still takes
a leap of faith to connect these pulsing colours with actual human
behaviour, the very existence of such images has succeeded where generations
of academics failed. The end result has been to demystify the brain.

It is a significant part of Dr Peters' appeal that he is not just a
psychologist but a psychiatrist, a man with a handle on cerebral biology.
Athletes find him convincing because, where others just want to talk about
feelings, he can also project diagrams onto the wall. "I had one-on-one
meetings with him," said Steven Gerrard this week. "And I understand the
different parts of the brain … and why you think certain things."

For most psychological purposes, brain scans remain a sort of scientific
window-dressing - like the moment in the shampoo ad where "pro-vitamin"
molecules go flying into hair strands. Thus far, they have done more to
change perceptions than revolutionise our understanding.

But progress is relentless and there may come a time when athletes' brain
patterns are tracked in real time along with their on-field positions.
Chelsea Football Club already have a "mind room" - an idea borrowed from AC
Milan - where their players are fitted with electrodes while watching
replays of dramatic on-field incidents.

The idea, once again, is to help Chelsea's players control their responses.
Mind you, if everyone manages to cage their inner chimp, sport could become
a disappointingly monochrome business. Where would we be without the odd
meltdown?