Dopamine and the origins of human intelligence.
A general theory is proposed that attributes the origins of human intelligence to an expansion of dopaminergic systems in human cognition. Dopamine is postulated to be the key neurotransmitter regulating six predominantly left-hemispheric cognitive skills critical to human language and thought: motor planning, working memory, cognitive flexibility, abstract reasoning, temporal analysis/sequencing, and generativity. A dopaminergic expansion during early hominid evolution could have enabled successful chase-hunting in the savannas of sub-Saharan Africa, given the critical role of dopamine in counteracting hyperthermia during endurance activity. In turn, changes in physical activity and diet may have further increased cortical dopamine levels by augmenting tyrosine and its conversion to dopamine in the central nervous system (CNS). By means of the regulatory action of dopamine and other substances, the physiological and dietary changes may have contributed to the vertical elongation of the body, increased brain size, and increased cortical convolutedness that occurred during human evolution. Finally, emphasizing the role of dopamine in human intelligence may offer a new perspective on the advanced cognitive reasoning skills in nonprimate lineages such as cetaceans and avians, whose cortical anatomy differs radically from that of primates.
Previc
F H
FH
Flight Stress Protection Division, Brooks Air Force Base, Texas. fred. previc@brooks.af.mil
D000818:Animals; D005075:Biological Evolution; D001833:Body Temperature Regulation / Q000502:physiology; D002490:Central Nervous System / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D015186:Hominidae / Q000502:physiology*; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D008568:Memory / Q000502:physiology; D009043:Motor Activity / Q000502:physiology; D011340:Problem Solving / Q000502:physiology; D014443:Tyrosine / Q000502:physiology
D014443:Tyrosine; D004298:Dopamine