The plants also look different. Blackberries are much larger reaching heights of six to ten feet tall. Raspberries will get about three to four feet tall. And of course the taste; Blackberries have a mild, sweeter flavor than the tart wild raspberries. All of which I can't really convince you of with my close up photos.
So there you go. I am indeed picking wild raspberries in North West Indiana. I hear there might be some blackberries around here too, but I haven't found them yet.