As a student of psychology I believe that what we call "instincts" are more complex than we understand. We say that humans don't have them because we understand ourselves better than animals. The more research that is done however, the closer animal behavior seems to human behavior. Bonobos for instance have been witnessed caring for injured animals and testing has shown that many animals undergo the same chemical reactions in the brain that humans do when exposed to emotional triggers. Also, there is evidence that tickling/tickle defense is instinctual. The automatic motions of children being tickled are now thought to be a basic, hardwired form of grappling.