Language is one of the most notable abilities humans have. It allows us to express complex meanings and transmit knowledge from generation to generation. The evolution of the language would be related to another notable feature of the Homo Sapiens: tolerance and human cooperation. 

      In a study regarding language, authors show how the activity of glutamate releases dopamine into an evolutionary old brain structure important for learning. Alterations in the balance of stress hormones in the body were an important advance in the evolution of vocal speech in the lineage of modern humans.

      “These results suggest the glutamate system and its interactions with dopamine are involved in the process in which humans acquired their varied and flexible ability to speak.” stated Thomas O’Rourke, an author of the study.

      This is rooted in the idea that humans tamed themselves. This self-domestication hypothesis, started by Charles Darwin, says that when early humans started to prefer cooperative friends and mates to aggressive ones, they essentially domesticated themselves.

      Natural selection against reactive aggressiveness in our species would have altered the interaction of these neurotransmitters and promoted the communicative skills of our species, shedding  light on new ways for comparative biological research on the human ability of speech” researchers concluded.

      After reading this general background, junior Emily Romen had to say “ I had no idea this was a thing. It’s super interesting how we’re able to learn so much about ourselves from other species!”.

      Multiple studies implicate hormone balances signal genes in the vocal learning abilities of songbirds differences between the domesticated Bengalese finch and its closest wild relative. It’s proposed that attenuated stress under domestication can bring about more variety in the vocalizations.

      With these, it shows that the reduction of reactive aggressiveness, resulting from the evolution and process of self-domestication of our species, could have led to an increase in the complexity of speech. 

      This development caused by the lowest impact on brain networks of stress hormones would be crucial when learning to speak. The evolution of language can be more easily investigated by comparing the communications systems of other animals.

      Moreover, although speaking and bird singing evolved independently, it is suggested that both communication systems are associated with similar patterns in the brain connectivity and are negatively affected by stress. “Birds that are regularly under stress during their development sing a more stereotypical song as adults, while children with chronic stress problems are more susceptible to developing repetitive tics, including vocalizations in the case of Tourette syndrome.”

      Studies have likened this to the way that children learn to speak and how birds sing. Unlike most other species communication systems, birds and kids can only be properly developed under the supervision of an adult. Without the presence of an adult the young birds, or kids, would not have the proper range and meaning of sounds to communicate.