Instincts and reflexes
A squirrel hardwired to crack a nut at birth.
Here below are some common instinctive behaviors exhibited by humans.
Infant smiling.
People raise eyebrows when greeting somebody.
Congenital fear of snakes and spiders.
People recognize anger, disgust, sadness
Humans are territorial.
Goosebumps appear as a response to anger or fear. The erect hairs make the animal appear larger, in order to intimidate enemies.
Response to smell from the sweat of the terrified person.
