Humans have likely spent the vast majority of our history as a species in relatively egalitarian, small-scale societies; this does not mean humans are by nature egalitarian, but that ecological & demographic conditions suppressed dominance

Making and unmaking egalitarianism in small-scale human societies. Chris von Rueden. Current Opinion in Psychology, Volume 33, June 2020, Pages 167-171. https://doi.org/10.1016/j.copsyc.2019.07.037

Highlights
•    Modal political organization of ancestral human societies is egalitarianism.
•    Role of prestige in human hierarchy is a contributing factor to egalitarianism.
•    Historical shifts to greater inequality include coercive and non-coercive forces.

Abstract: Humans have likely spent the vast majority of our history as a species in relatively egalitarian, small-scale societies. This does not mean humans are by nature egalitarian. Rather, the ecological and demographic conditions common to small-scale societies favored the suppression of steep, dominance-based hierarchy and incentivized relatively shallow, prestige-based hierarchy. Shifts in ecological and demographic conditions, particularly with the spread of agriculture, weakened constraints on coercion.

Check also: Romanticizing the Hunter-Gatherer, Despite the Girl Infanticide, the Homicide Rate, etc.

Romanticizing the Hunter-Gatherer. William Buckner. Quillette, December 16, 2017.  https://www.bipartisanalliance.com/2017/12/romanticizing-hunter-gatherer-despite.html