One of those ideas is one referred to by Tom Wolfe in his Jefferson Lecture. Do a search for "Jose Delgado" in the text and start reading, and when you're done start thinking about the implications that idea has for free will. Other people clearly have, and while some of it seems to verge on tinfoil hat territory, still, it makes you wonder. If your personality is shaped so strongly by those around you, then what of free will?
Perhaps the answer is in rejecting the "or" answer in favor of an "and" answer. It's easier to be affected by those around you if your ego isn't fully developed or if you grow up in a society where group satisfaction is more important than individual happiness. We're all familiar with the "peer pressure" and "groupthink" phenomena - and with the countervailing notion that one should rebel against these phenomena in favor of doing what is right.
On a more practical level, it struck me that Delgado's research got sidetracked by the psychiatric profession because it came at a time when the biological explanations for mental illness were falling out of favor and being replaced by the Freudian and Jungian view of things. Lobotomies were being increasingly seen as an unacceptable answer to the mental illness problem, and sticking wires in peoples' brains, whatever the positive results, probably seemed all too similar - just another means of patient management, as opposed to an actual cure. These days, the concept is probably further tainted by the "wirehead" in fiction, depicted as a high-tech version of today's drug addicts.
Still, you have to wonder. Would all the addicted, alcoholic, and insane homeless - to say nothing of those who are functional but still damaged - be any worse off if they had chips in their heads that fixed their problems? We turned those people out into the streets because we wanted to close the hospitals and it seemed less expensive to have them come back for their drugs (which they didn't) but clearly that hasn't worked. Seems we ought to at least think about it.