I would like to share with you a little fragment of a book im reading now.
"the food of gods by terrance mackenna".
"The evolutionary advantages of the use of speech are both obvious and subtle. Many unusual factors converged at the birth of human language. Obviously speech facilitates communication and cognitive activity, but it also may have had unanticipated effects on the whole human enterprise.
Some neurophysiologists have hypothesized that the vocal vibration associated with human use of language caused a kind of cleansing of the cerebrospinal fluid. It has been observed that vibrations can precipitate and concentrate small molecules in the spinal fluid, which bathes and continuously purifies the brain. Our ancestors may have, consciously or unconsciously, discovered that vocal sound cleared the chemical cobwebs out of their heads. This practice may have affected the evolution of our present-day thin skull structure and proclivity for language. A self-regulated process as simple as singing might well have positive adaptive advantages if it also made the removal of chemical waste from the brain more efficient. The following excerpt supports this provocative idea: Vibrations of human skull, as produced by loud vocalization, exert a massaging effect on the brain and facilitate elution of metabolic products from the brain into the cerebrospinal fluid (CSF) . . . . The Neanderthals had a brain 15% larger than we have, yet they did not survive in competition with modern humans. Their brains were more polluted, because their massive skulls did not vibrate and therefore the brains were not sufficiently cleaned. In the evolution of the modern humans the thinning of cranial bones was important.
As already discussed, hominids and hallucinogenic plants must have been in close association for a long span of time, especially if we want to suggest that actual physical changes in the human genome resulted from the association. The structure of the soft palate in the human infant and timing of its descent is a recent adaptation that facilitates the acquisition of language. No other primate exhibits this characteristic. This change may have been a result of selective pressure on mutations originally caused by the new omnivorous diet."