One-finger swipe?

Hey guys, I had my Mac Book pro for about a couple of weeks now, and for the last couple of days I have noticed that when i drag one finger to the top left or right side of the screen it behaves as if I was trying to do a downward four-finger swipe, where it fans out all the applications that are open currently (sorry I really don't know any other way of explaining it). And I have looked through my settings for the track pad swipe options and there is nothing under four-finger or one finger swipe. I tried it on another Mac book pro and it seems as if it was unique to mine. Anyone know how I disable this option or if there is an issue, how I can resolve it?

Please, and Thank you.

Welcome to Mac Forums.
They are called "hot corners."
If you go >system preferences>desktop and screensaver>screensaver tab>hot corners tab> you can set them all to do what you want

Thank you so much! I can see how they can be helpful at times but for me its just annoying.;D