[Retric]

It's related to early brain research which discovered some left right specialization. Medically it's been mostly debunked, but for some reason "Pseudo Science" people really latched on to the term.

PS: By “debunked” it was discovered that the brain has more plasticity in how and where specific tasks where preformed that initially assumed. Also the high level understanding of what doing “Math” or “Poetry” has little connection to how the brain actually does this stuff. EX: Some people can count time accurately why reading other people can’t. The most probable explanation as you grow up the brain chooses how to approach high level problems in a fairly arbitrary fashion.