Less intelligent: Users of Internet Explorer were found to have lower IQs. Superior: Users of Firefox were found to be more intelligent.

They have long had to grapple witha catalogue ofbugsand viruses. But now users of Internet Explorer have another reason to feel humiliated - they are more stupid too.

A study has found that those with Internet Explorer 6 installed on their computer typically have an IQ barely higher than 80 - which by some rankings makes them almost retarded.

This compares to those who used Firefox or Google’s Chrome who came in at around 110. Users of Opera or Camino were top with an IQ of around 120.

A ranking of a mere 80 might explain why millions of people around the world continue to use Internet Explorer even though it is an inferior web browser. Some 10 percent of computers are thought to have the software installed on their home or office computer.

The study, by Vancouver-based psychometricconsulting company AptiQuant, examined IQs or Intelligent Quotient which is a measurement of a person’s intelligence worked out on the basis of special tests. The average is 100.

AptiQuant polled 101,326 people aged 16 and up from countries including the US, Canada, Britain, Australia and New Zealand.

Subjects were asked to take an intelligence test which recorded their operating system and location via their IP address. A ranking of 70-80 is seen as borderline retarded, while 80-90 is below average.

A score of 110, where Firefox and Chrome users are, is above average, while the 120 ranking of Opera or Camino users is considered superior.

Internet Explorer has long been the subject of ridicule on account of how bug-ridden it is. Earlier this year Microsoft announced that all versions of the browser were at risk of being hacked due to a flaw in the program.