No we don't but if you have read the bible, it is that we didn't get the 10 commandments until sometime after humans were created. So that gave them their sense of fear. Before that, I am going to assume that men feared nothing. To show this, look at Adam and Eve. Adam was told to not eat the apple and the snake convinced him to do it. He didn't fear god like people do now. If he did, then he would have not eaten the apple.