Update: This study appears to be a hoax. For details, click here.

Original: A research firm posted an IQ test on its Web site and then compiled the results from more than 100,000 users.

It found that there was no substantial difference between users of Chrome, Firefox, Safari, and Opera.

But Internet Explorer users had IQs below average.

That's a switch from five years ago, when IQs were more or less the same across all browsers.

The company, Aptiquant, bills itself as a "psychometric consultant." Its main business is creating tests to help businesses hire well.

Now before all you Opera users get too satisfied with yourselves, there are lots of possible reasons why IE users scored so low:

IE has about twice the installed base of any other browser, so IQs are more likely to tend toward the mean.

IE is the default browser of 95% of people who don't know how to download and install a new browser, which drags down the average. (Mac users in this boat stick with Safari.)

People who use other browsers include a disproportionate number of computer geeks, which brings their averages up.

Online IQ tests -- or IQ tests in general -- are silly.

IE users really are kind of dumb.

Whatever the reason, here's a chart showing the average IQ of users for each browser in 2011 (red) and 2006 (blue):

And here's a chart showing the percentage of people in each IQ percentile who use each browser -- for instance, Firefox (the dark green line) has a low percentage of dumb users (on the left side of the chart) but the highest percentage of average (middle) and smart (right) users.

Bigger versions of the charts are available in the study. You can download and read it for yourself here (PDF file).