It is problematic to think physical strength was crucial to human survival.  If the original condition demanded this, how could we succeed the Neandertals?  They had markedly larger muscles than we.  Moreover, this does not explain one of our secondary sex characteristic.  Men have on average more muscles on their upper body than women.  If physical strength was so important should it not be the same?  After all, there are about as many women as men.

For this reason I think physical strength was not so important in all contexts.  We can often compensate by using our brains.  Partially by making tools and partially by cooperating.  While toolmaking is obvious, cooperation is often forgotten.  Maybe it is the old myth that humans originally lived alone or in single nuclear families?  People have in fact never lived like this.  We always had friends and further relatives.  Cooperating with these was the key to survival.

So how did this cooperation look?  In some cases it has been a matter of collaboration.  Otherwise, it was about mutual exchange of goods and services.  Such types of cooperation require one to have a roughly sensible idea of what others can and want.  Therefore I think humans are made to be able to learn to know each other.  Provided they get a chance, of cause.

This social life can also explain why we have conscious reflection.  There have been many situations where automatically treating “one” as synonymous with “all” simply does not work.  (This is just one example of dysfunctional automatic thinking.)  So our capacity for conscious reflection evolved to avoid such things.

It is important to understand that general authority did not exist.  What authority one had depended entirely on competence on the subject.  Imagine he who killed an elephant years ago and still brags about it.  Say that he would try to nit-pick how others cook root-vegetables.  Then people would just laugh about him.

Please note that humans originally lived in groups of at most a thousand people.  Such groups have no need for formal political leadership.  The intervention of common acquaintances could do enough to prevent “the war of all against all”.  On the other hand, there were no resources to sustain certain individuals which only did one thing.  For this reason I don’t think we can talk about “the world’s oldest profession”.  (That it would be prostitution is Rudyard Kipling’s idea.)  Instead I think there are several professions which arose at about the same time.  These include politician, judge and priest.  Things like slavery, wet-nursing and prostitution I think arose somewhat later.

That there were no such positions of power also writes off certain behaviours.  Labelling other members of the society evil and demanding their submission would be outright self-destructive.  Same thing with threatening to murder and rape for being told something one does not want to hear.  Such things are not “dominance instincts” since such dominance did not exist.  Instead, they are bad habits originating in abuse of power.  We did not have any positions of absolute power from start.  This makes us unable to handle them.

Another result of small groups is you can’t kill each other too often.  A group of people doing this would not have been able to uphold their number.  If you spread it out over a human lifetime the risk of being killed was very high.  But this does not mean violence between humans was in any way part of everyday life.  Murders would happen years apart and wars decades apart.  Moreover, the wars were short-term to gain an immediate advantage.  Attacking other groups “for the sake of your own” without knowing how the conflict started was completely alien to them.

Neither did it not work having too many “cheaters” either.  That is individuals which did not contribute anything.  Not even knowledge as the elderly does in these societies.  Adult “cheaters” use resources which could sustain children.  This is why psychopaths are so much rare.  Their frequency is estimated to 1 – 3 percent.  The difference is due to various scientists using different definitions.  Moreover, it is hard to tell the difference between those who can’t care and those who just habitually don’t care.  The latter is mostly caused by adverse environmental conditions.