How often have you talked to yourself? Pretty often? Hardly ever? Ashamed to admit how often? According to recent research talking to yourself in the second person is highly motivational. If you tell yourself "I can do it" it is not half so compelling as saying "you can do it" to yourself out loud or in a whisper or deep in your mind That might be why President Obama's "yes we can" slogan has faded a little -'cause no one was specifically delegated, now if he'd said - but I don't want to go there.
I read an article on the findings of some research for this on the Forbes magazine website. Apparently some research results were also posted in the European Journal of Social Psychiatry. I'll be honest, I skimmed through the article in Forbes and I didn't read the other one. The study was not considered complete because it was not known how this approach actually affected the carrying out of tasks. So your guess is as good as mine as to whether this really works.
My guess for what it's worth is that it will work sometimes and other times not simply because in our deepest depths we know what we can and can't do. I do not have a head for heights so it's no good me psyching myself up to climb a mountain by repeating "you can do it". Sure I could do it - if there were 10 hungry grizzly bears on my tail and even then I have my doubts I'd get beyond the first ledge. But I wouldn't need to talk to myself about it, I'd just run and start climbing and that would be adrenalin and the determination to survive which is inbuilt in all of us.
I talk to myself about all sorts of things. "Now where did I put that?" is a very frequent question. It's normal and it does help. I don't think we needed a clinical study to find that out. Either it works for you or it doesn't. With so much written on human behaviour, how to understand it and get the best for yourself out of it, you'd think we should be beyond all these new ideas and concepts. The first work of this kind which I ever read was the Dale CArnegie classic How to Win Friends and Influence People. I find it fascinating to this day. Nothing has really changed in human nature since he wrote that book all those years ago. The basic principles still hold good today. It's both a sobering and a comforting thought.
So keep talkin' if that's what works for you.