Which expert should I believe?

As a reader of this journal you are probably a professional scientist with an interest in communicat­ ing the importance of what you do to the world at large. We share that interest, and advertise to journal­ ists the work we publish that we feel most likely to be of general interest, via press releases on the EurekAlert! website. This works very well, and papers in Current Biology are frequently covered in the general media. This is all fine and dandy; good for us, our authors, the science journalists and their readers.... There is an aspect of this process that is, I believe, deadly serious and of the utmost importance. In certain areas of science, public understanding has an influence on behaviour with serious consequences — this is especially true of medical and environmental matters. Take the recent case in the UK, where there was a report suggesting a possible link between the triple MMR vaccine and autism: this received a great deal of publicity and was followed by a reduction in vaccination levels to dangerous levels, exposing the population as a whole to increased risk of infection. The potential link was never accepted as strong evidence by the majority of specialists in the field, some initial supporters have recanted, and the claim has now largely been refuted. But doubts linger among parents, confused by apparent differences among 'experts' in the field — the British Medical Journal, for example, has recently reported that uptake of MMR among two-year-olds in the UK fell from around 92% in early 1995 to around 80% in 2003/4 (see the recent story on the BBC news website, with some interesting reactions from the general public: http://news.bbc.co.uk/1/hi/health/ 4539887.stm). Or consider global warming: this is another situation where the behaviour of the population as a whole is crucial, as we all contribute to the global carbon dioxide level. Public belief is of huge importance here, as only when there is clear acceptance of the problem and the need to address it will politicians be persuaded to implement measures that may, in the short-term at least, be perceived by their electorate as providing downward pressure on their standard of living. Again, the public is confused by the impression of 'mixed messages' from 'experts'. There is a common belief that there is serious disagreement about whether global warming is a real phenomenon, and whether it is 'scientific fact' that …