Neuroscientists challenge tenets of intelligence testing. “Many people underscore on IQ tests because the benchmark memory test is inaccurate, a US researcher told the Society for Neuroscience meeting in Orlando, Florida yesterday. Another announced that women’s brain size could affect IQ.

In standard intelligence tests, subjects are asked to remember a string of random numbers. The widely quoted average before stumbling – seven, give or take two – is thought to reveal the capacity of our short-term memory.

This ‘magic number’ is a huge overestimate, claims Mrim Boutla of the University of Rochester in New York. She puts the real size of short-term memory at four digits, plus or minus one – so too do several other studies challenging the gold standard.” Nature