Health, thinking skills linked to same genes

Genes that influence people's health also shape how effectively they think, a study shows.

An international team of scientists has found that genes associated with diseases that include Alzheimer's, schizophrenia and autism also have an impact on some cognitive functions.

The team analysed health data from about 100,000 people. When it compared each person's mental test data with his gene data, it found that some traits linked to disease and thinking skills shared the same genetic influences.

Professor Ian Deary, director of the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh, who led the research, said in a statement: "In addition to there being shared genetic influences between cognitive skills and some physical and mental health states, the study found that cognitive skills share genetic influences with brain size, body shape and educational attainments."

Fellow researcher Saskia Hagenaars said: "The study supports an existing theory which says that those with better overall health are likely to have higher levels of intelligence."

Conspiracies with too many people don't last

If you're thinking of creating a massive conspiracy, you may be better off scaling back your plans, according to an Oxford University researcher.

While we can all keep a secret, a study by Dr David Robert Grimes published in the journal PLoS ONE suggests that large groups of people sharing in a conspiracy will very quickly give themselves away.

Said Dr Grimes, a physicist, science writer and broadcaster: "A number of conspiracy theories revolve around science. While believing the moon landings were faked may not be harmful, believing misinformation about vaccines can be fatal."

Dr Grimes created an equation to express the probability of a conspiracy being either deliberately exposed by a whistle-blower or inadvertently revealed by a bungler.He calculated that four major conspiracy theories, including hoax moon landings and climate change fraud, would all have been exposed in fewer than four years if they were true.

He also looked at the maximum number of people who could take part in an intrigue in order to maintain it. For a plot to last five years, the maximum was 2,521 people. A century-long deception should ideally include fewer than 125 collaborators.

Said Dr Grimes: "I hope that by showing how unlikely some alleged conspiracies are, some people will reconsider their anti-science beliefs."

Compiled by Lin Yangchen