For Hindus, it's a part of their regular religion rather
than a weird and unusual event. I think most modern cases
come from India.
The race thing is interesting but modern sceptics have also
noticed that some Indian youngsters have attached
themselves to higher caste families by claiming to be
reincarnated sons or daughters.
People have been found to contain multitudes, especially
under hypnosis. In the nineteen twenties, an American
housewife called Pearl Curran started to write historical
novels dictated by an altar ego. They were said at the
time to have impressed the historians, though they are
seldom seen now.
Many anomalous phenomena seem to be classified under
different headings for different degrees of duration. The
temporary Spirit Guides and channelled entities of a medium
do not seem very different from the more extended identity
crisis of the "reincarnated" soul.
One of the classic early German cases had an orphan girl
who was able to recite swathes of Latin, though it turned
out that she had spent her earliest years in the care of a Pastor,
where she may have picked it up parrot fashion.
It is said that we forget nothing. It is also true that the split
mind can process information unconsciously and create competing
identities. How far we can tune in to other places and other
minds is always a matter of speculation.
I guess reincarnation is just another form of expanded consciousness.