Some say man heart is evil from his youth. Man develops his own ego from an early age to survive. He is inferior to other animals in the physical force and thus developed his mental power. The feeling of separateness gives him the feeling that he is at the center. He develops a will to get what he can to survive.
“I will never again curse the ground because of man, for the intention of man’s heart is evil from his youth”
Genesis 8, 23