Anyone who has had a child can probably attest to the fact that our progeny repeat patterns in our own lives in uncanny ways. My daughter is two years old. She has a nascent phobia of bugs that her mother also had when she was a wee one. Our child also seems to be getting night terrors where spiders are crawling on her etc… My wife suffered from these as well though the frequency has been lessening as she has aged and she hasn’t had such a nightmare since our daughter was born. The other way in which they are similar is that my wife had an intense dislike of walking on grass when she was a child just as our daughter has.
I don’t think any of these behaviours could have been learned since my wife hasn’t evinced any of these symptoms or behaviours in front of our daughter. I also don’t believe there could be some unconscious tension that is transmitted to the child when we encounter bugs or grass. If children responded to such subliminal stimuli then I would have to believe they would have even a higher incidence of phobias towards such things as traffic or a million other things that cause huge amounts of stress in our lives that are manifested in obvious ways that even a child can see. It seems that since snakes and spiders etc… are common objects of phobias that there must have been an evolutionary advantage at one time to staying away from such things. I have also done some research on agoraphobia since I have suffered from it off and on throughout my life and the studies that I saw at the time indicated that it was probably genetically inherited and passed along from one generation to the next as a recessive trait.
There are also a lot of mannerisms that are passed on but it is harder for me to argue that these are not learned since most of our mannerisms (such as twirling our hair under stress or crossing our legs a certain way) stay with us throughout life.
But what is the state of science on these issues? Are complex behaviours inherited and if so, which ones and by what mechanism are these behaviours incorporated into the genetic complex?