Such questions are incredibly exciting and important for understanding the world better. And there are some cases that answer such questions.
The following documentary shows that children who grow up under extreme conditions have completely different behavior than “normal” people. Oxana MalayaFor example, the girl who grew up among dogs for 6 years behaved more like a dog than a human. She couldn't speak or walk, but ran on all fours, like a dog.
Also Genie grew up in extreme isolation for more than 10 years, could not speak and showed completely different behavior than children of the same age.
What is also interesting is that these people were able to learn “normal behaviors,” such as speaking and walking on two legs, but only to a limited extent. That's obvious, because if you haven't learned to speak properly by the age of 13 years and 7 months, it will be very difficult for you to understand something like that properly. As shown in the documentary, the brains of feral children are smaller and malformed:
Here is the whole documentary:
So people are a product of their environment (their experiences), just like you and me. This is described in more detail in the book “Behaviour: from genes to gender”:
When I think about my own childhood now, it's somehow absurd. Have you ever had conversations about human behavior? About science and how science works? Has my curiosity about the world been awakened? Honestly no…
You come out of school and you can read and write, do some complex math, maybe Latin, maybe French and economics. I had that as a core subject in my Abitur. I was well prepared to become a blue-collar worker or haphazardly study business, like thousands of others do every year, and then sit in a marketing department and sell stuff. Congratulations society!
Luckily, I went traveling and had free time to learn more about the world.