A neurochemical hypothesis for the origin of hominids.

Title

A neurochemical hypothesis for the origin of hominids.

Creator

Raghanti Mary Ann; Edler Melissa K; Stephenson Alexa R; Munger Emily L; Jacobs Bob; Hof Patrick R; Sherwood Chet C; Holloway Ralph L; Lovejoy C Owen

Publisher

Proceedings of the National Academy of Sciences of the United States of America

Date

2018
2018-02

Description

It has always been difficult to account for the evolution of certain human characters such as language, empathy, and altruism via individual reproductive success. However, the striatum, a subcortical region originally thought to be exclusively motor, is now known to contribute to social behaviors and "personality styles" that may link such complexities with natural selection. We here report that the human striatum exhibits a unique neurochemical profile that differs dramatically from those of other primates. The human signature of elevated striatal dopamine, serotonin, and neuropeptide Y, coupled with lowered acetylcholine, systematically favors externally driven behavior and greatly amplifies sensitivity to social cues that promote social conformity, empathy, and altruism. We propose that selection induced an initial form of this profile in early hominids, which increased their affiliative behavior, and that this shift either preceded or accompanied the adoption of bipedality and elimination of the sectorial canine. We further hypothesize that these changes were critical for increased individual fitness and promoted the adoption of social monogamy, which progressively increased cooperation as well as a dependence on tradition-based cultural transmission. These eventually facilitated the acquisition of language by elevating the reproductive advantage afforded those most sensitive to social cues.

Subject

*Ardipithecus; *basal ganglia; *Biological Evolution; *dopamine; *hominin; *Neurochemistry; *neurotransmitter; *Selection; *Social Behavior; Altruism; Animals; Corpus Striatum/*physiology; Dogs; Genetic; Humans; Personality; Primates; Social Conformity

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

E1108–E1116

Issue

6

Volume

115

Citation

Raghanti Mary Ann; Edler Melissa K; Stephenson Alexa R; Munger Emily L; Jacobs Bob; Hof Patrick R; Sherwood Chet C; Holloway Ralph L; Lovejoy C Owen, “A neurochemical hypothesis for the origin of hominids.,” NEOMED Bibliography Database, accessed April 16, 2021, https://neomed.omeka.net/items/show/4058.

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