Hi, I was wondering how much trauma to the head it would take to bring about a noticeable negatively affected cognative ability particularly as it pertains to the expression of self-efficacy. I recieved an injury to the upper part of my head, just above the hairline when I was in my late teens which caused a small tear in my scalp and pushed the bone in my skull back such that the result was that I have been since left with a bump in the bone and a crease just behind it. I recieved a concussion as a result of the injury but never went to see a doc about it at the time nor have I reported it since. The only noticeable outward signs of the injury are white hair growing from the region of impact and if one was to feel the area, like I said, they'd feel a noticeable bump and crease (which currently are hidden by hair). Thanks.