Long time ago I read that a human baby is born without fears but for two: fear of falling and fear of loud/abrupt noise. Rest of the fears that young or adult human fears are learned by imitation (of people around), experience (of danger), information (of cause of danger) and/or warnings (from parents, etc.). Some of the fears are legitimate for child to learn for survival (viz. fire, insects, sharp object) and others just make person coward (viz. darkness, ghosts). It will be interesting to test this theory by imagining what are things a adult is afraid of and of those what a newborn is afraid of innately.
Why only these two fears are innate is even more interesting since fetus doesn’t experience falling and loud noises in womb? So if these are not fears learned inside womb, are they genetically wired? Why did millennia of evolution chose to wire only these two fears instinctively into a human (after all loud noise could never kill anyone) whereas one would imagine fear of death, fire and starvation are more critical for survival of early human.
Among the learned fears, child goes through a stage of development where each fear enters into his life. Here is nice summary of 1993 research into children and fears. The very first learned fear is fear of separation of parents, and child learns within a year than when parents go away, they do return back. Within next five years, fear of darkness, lightening, strange animals, strangers and death make home in child’s mind. As child matures into teens, common fears such as fear of public speaking, failure, rejection, loneliness, injections, hospitals, injury, accident, etc. add to repository. Above article includes a table with list of common fears with age.
Apart from innate fears, a newborn is also armed with innate skills which are either forgotten or sharpened with time. Skill to suckle and breath are innate and aren’t required to be taught which help infant survive. I also remember reading that human infant also knows swimming, just like youngs of other animals, and forgets it because of lack of practice. Apparently, leaving newborn into a bathtub will have him swimming, though parents will not attempt trying that due to fear of drowning. This has been tested though under supervision of doctors and life saving machinery.