The old saying that ontogeny recapitulates phylogeny refers to the fact that changes an embryo undergoes in the womb reenact the developmental stages animals went through during evolution. However, Homo sapiens have gone through enormous changes over the past 50,000 years largely due to language. Once born, we progress from a state of relative disorganization toward more complex, organized and differentiated brain functioning. We learn socialization, cooperation, contemplation and can participate in our own thought processes, a feat impossible before language. We also go through something Freud called the Oedipus complex, mastering primitive impulses which each of us put our own stamp on.
These changes mirror the complexity of civilization that has occurred since the adoption of language some 50,000 years ago. As civilization formed we learned the benefits of communal living and neutralized age old predators. We coalesced into government run metropolises. We created laws, education, science and religions. All of this was due to the cognitive advances born of language. Taboos were incorporated into our minds as repressions and in some cases neuroses.
The child recapitulates Homo sapiens’ startling advances as it matures. Some fail at this, resulting in mental illness, a return to the primitive. There are also, no doubt, neurotransmitter transformations in all of this, specifically the suppression of dopamine which can aberrantly result in illnesses as diverse as schizophrenia, Tourette’s, Parkinson’s disease, stuttering, attention deficit disorder, Huntington’s chorea, substance use, and more. The implications are staggering and, if understood, offer a rich soil for intervention.