Martin McKee, from the London School of Hygiene and Tropical Medicine, and David Stuckler from the University of Oxford argue that "it is possible for two well-informed groups of people faced with the same evidence to reach completely different conclusions about what should be done."

They highlight a recent American study where three groups who described themselves as either Democrats, Republicans or Independents were randomly given four versions of an authoritative news story about diabetes. The stories were exactly the same apart from how they described the causes of diabetes -- one said nothing while the other three alluded to genetic factors, individual lifestyle choices and social determinants such as economic status.

Interestingly, the Democrats and Independents were far more likely to agree with the social determinants explanation but this had no effect on the Republicans. Furthermore, the Democrats were significantly more likely than the Republicans to support action to tackle diabetes, such as restrictions on junk food.

The authors also refer to a study on brain activity in Democrat and Republican research participants who were exposed to contradicting messages from both parties. They say: "Whereas those registered as Republicans clearly identified the contradictions voiced by Democrat politicians, they saw minimal contradiction in the statements by Republicans, and vice versa."

They conclude: "Politicians are often criticised for being all things to all people and for making promises that they then fail to keep. However … the problem may be less what the politicians are actually saying but rather how their words are heard and interpreted."

Note: If no author is given, the source is cited instead.

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