I don't know why I haven't heard of this before. My boyfriend came across this and thought because of my psychology interest that I should look it up. If you haven't heard of this story, it definitely is one to give attention to.
To brief it for you, a girl was neglected for several years. During this neglect the girl was not taught anything, just severely neglected. So at seven years old she was like an infant, couldn't talk, wasn't potty trained and barely knew how to use her hands among so much more. I can't seem to find the words to describe how this story makes me feel. You'll have to read/listen to it to understand the feelings for yourself.
Here are some links:
Audio of the article