Although the word rejection was not used until 1415, the experience of it dates much further back.
In the case of mankind, it was prevalent within the very first tribes. The San people in Africa were the first hunters and still survive to this day. Whether it was a small section of this tribe or another African tribe that first crossed the Red Sea 70,000 years ago and colonised the rest of the world, has never been fully established.
However, one commonality between these tribes was their ability to ostracise a member. Cast out from the tribe, the individual would not be expected to last long on their own.
As with the animal kingdom, hunting is most productive in packs. Their conflict with the group whose only learning mechanisms were the experiences of their ancestors, who practiced the exact same rituals, meant they had little chance of being accepted again.
This in itself could crush the individual far more than hunger, because humans have a built-in yearning to belong to a tribe.
Belonging and being accepted is part of the human genome. When a member was cast out, they would become emotionally destabilised. They would have spent their entire life within the tribe. Existing outside of it would never have occurred to them. The tribe's rejection of them was against everything their genetics felt comfortable with.
The individual member would experience the gut-wrenching pain of rejection. They would have no support group to turn to. They would have no text to guide them on their next path. Ostracised from their tribe, their only company was their own thoughts. Any other species would most likely wither up and die. But mankind has an extraordinary ability to survive.
The studies of evolutionary biologists reveal that as the tribes evolved, their brains developed alert signals when they were on the cusp of being ostracised. They did not let rejection end the human race. They learnt from rejection. The experience of it enabled them to adjust their behavioural patterns to become more accepted within the tribe. In some cases the member would probably have become a leader. An example to others. Rejection was not something to retreat from, it was something to confront head on. It was not an experience that led to someone quitting. Instead it became the defining moment in their own evolution. Rejection taught them to become better humans.
Today, one does not need to go into the deepest jungles or the remotest parts of Africa to find tribes. They co-exist in every town and city on Earth. New terminology reflects their existence: 'circle of friends' 'family' 'team' 'crew' 'troop' 'organisation' 'squad' and many more. They are the modern day tribes. The need to belong to one, or adjust one's behaviour to avoid being ostracised from one, is as strong today as it was thousands of years ago. If rejected, one takes stock of their situation and comes back stronger. Instead of allowing rejection to be the end, evolution has changed our genetics to accept rejection as part of our journey to self-improvement. Humans have learnt that overcoming rejection soothes the pain of it. The warning system is still built into the human brain to fear its arrival, but the individual finds a way to persevere. They become better at what they do. They find a way to be accepted.
Rejection is a critical experience of human history. Humans would never have evolved without it.