There is a study done by AptiQuant. Which alleges that the users of any IE version are not sharpest tools (see what I did there) in the shed.
The story was then picked up by The Register and here is a snippet:
A comprehensive study of web users has determined that the dumber you are, the more likely you are to use Microsoft Internet Explorer.
After measuring the IQs of exactly 101,326 users and correlating their scores with the browser they had used to access the test, "There was a clear indication ... that the subjects using any version of Internet Explorer ranked significantly lower on an average than others," concludes the study, conducted by the Vancouver, Canada, psychometric-assessment firm, AptiQuant.