Boy, that Vince Young must be some smart cookie. He scored a whopping 6 on the Wonderlick test.
Culpepper scored around a 16 to 20 I believe.
Here's a chart on the average scores by positions and non-NFL people by Paul Zimmerman in "The New Thinking man's Guide to Pro Football."
Offensive tackles: 26
Tight Ends: 22
Middle linebackers: 19
Wide receivers: 17
The average scores in other professions look like this:
Bank teller: 22
Clerical Worker: 21
Security Guard: 17
This surprises me because I would think that QB's would have to be the smartest!