IQ tests have been controversial for years. Many argue that they are biased; others say that they give an incomplete view of intelligence. Indeed, a study published in an upcoming issue of the journal Neuron confirms that IQ tests are not an accurate predictor of intelligence. In fact, the researchers say that no single test - at least none that has been devised already - can give an accurate assessment of all types of intelligence.

The study was conducted using a survey that could be accessed by anyone in the world. The researchers expected that they would receive responses from a mere 100 or so people, but people descended on the study. Their findings, reported in Neuron, are a result of the data provided by 100,000 people of various ages and cultures who completed 12 cognitive tests. The tests assessed memory, reasoning, attention and planning abilities. The test also included a survey that asked about participants' background and lifestyle.

The study found that no single test explained the entire picture of intelligence. Indeed, differences in performance could be attributed to a wide variety of factors, including short-term memory and reasoning. The researchers used a functional magnetic resonance imaging machine to map out how the brain used its various cognitive abilities.

The researchers found that lifestyle and personal background also accounted for a wide variety of the differences found in the test results. For example, while brain training did not help, aging did negatively affect memory and reasoning abilities. People who suffered from anxiety generally performed poorly on assessments of short-term memory. Similarly, smokers performed poorly on short-term memory and verbal tests. On the other hand, people who regularly played video games performed significantly better than other groups of people on both short-term memory and reasoning.

The team will continue their research with a new version of the tests, which can be accessed here. They are interested in looking at other variations in cognitive ability though, in order to prevent bias, they do not say what the focus of their research will be.

RELATED STORIES