Evolution of human morality



Human evolutionary history

The family lines of human beings and of our nearest relatives, chimpanzees, split from each other 67 million years ago.  One of the first species in the Homo genus, Homo erectus, arose about 1.8 million years ago in Africa.  

It is thought that around 2 million years ago, the Earth underwent a drying and cooling phase which led to a shrinkage of the forests and an expansion of grassland environments in Africa, and so, an increase in the numbers of ground-dwelling monkeys that competed with the first humans for plant foods, obliging them to take up scavenging meat, and later, actively hunting big game; and to find vegetable foods not available to monkeys, such as deep-down roots and tubers, which could only be obtained and processed by adults.  

Homo heidelbergensis is thought to have descended from Homo erectus around 8 hundred thousand years ago.  There is evidence for Homo heidelbergensis making wooden spears, bringing large prey back to a home base, and using fire in a controlled way from about 4 hundred thousand years ago.  

Our species, Homo sapiens, is thought to have descended from the African population of Homo heidelbergensis about 2 hundred thousand years ago.  

Our sister species, “Neanderthal man”, Homo neanderthalis, descended from the European population of Homo heidelbergensis.  

Nova documentary on Homo erectus here



Origins of morality

It seems that the evolutionarily unique moral development of the human species can be traced to two fundamental factors: the existing social, moral and cognitive skills of our great ape ancestors; coupled with those early humans being forced to survive in a difficult ecological environment (the African savannah) where most of the easily obtainable food was already taken by ground-dwelling monkeys.  

The hypothesis is that this led to interdependence and cooperation within small groups, in the forms of cooperative breeding and cooperative foraging, which in turn gave rise to enhanced human empathy and taking the perspectives of others; shared intentions with shared outcomes; unconditional targeted helping; fairness, honesty, and monitoring of self and others (shame / pride / reputation).  Along with the various forms of reciprocity, these factors are the bases of human morality.  

The rise of large groups and the need for coordination, cooperation and trust within groups of strangers on a large scale led to cultural practices and organised religion, and the competition for resources between these expanded groups led to between-group opposition and warfare.