Depending on how life went for a person, they can turn out to be social, independent, full of life, and so on. What determines how people turn out the way they do is how they are raised. A loner is definitely one of the more unique ways of growing up and can have long-lasting effects on the people that grow up as one.
What is a Loner?
A loner, by definition, is a person who simply does not associate themself with others, whether it be peers, older people, younger people, etc. They most commonly are only-children (children with no siblings) who also do not talk or interact with other people.
My Experience
I was born an only child, raised as an only child, treated like an only child, and had the experiences that only children can actually have. No siblings meant that I had nobody to look up to nor have I had anyone look up to me. On top of this, I also never had many friends through grade school. My graduating class was a breath-taking thirty-two people. Hell, the college I go to is relatively small compared to other universities throughout America. I always find myself with extreme stage fright when I talk in front of even the smallest group of people. I am basically a textbook loner.
What can it do to a person?
One of the more obvious and long-lasting effects of growing up as a loner is a sense of social-awkwardness. When interaction with other people starts to become necessary (which is very early on,) they can become detached from people they did frequently talk to, have trouble getting attached to others, or in worst case scenarios, grow a large distrust in other people all together. However, growing up as a loner is not necessarily always bad. Sometimes, the detachment from other people growing up can cause an even stronger attachment to other people when it becomes an everyday lifestyle. It can make them friendly towards others to some, it can fill a void that has been suppressed since they were born.
Loners can either be some of the least trusting people you could be around but you have to take their past environment into consideration before you make a serious judgement.