Can I have a word in your ear? Because I know what people are thinking. Yes, I know I told you the same thing last week. And I’ll keep mentioning it. Because if I say it often enough, you’ll begin to believe it really is what people are thinking.

Psychologists have found that, if you want the public to buy an opinion, you should persuade many people to voice it. But – and this is alarming – you can achieve comparable success by getting just one person to repeat the same opinion over and over. The key is to make that opinion seem familiar. Familarity, it seems, breeds belief.

A group of American researchers, led by Kimberlee Weaver, of Virginia Polytechnic Institute and State University, enlisted more than a thousand students to voice opinions in controlled settings. The experiment’s conclusion is encapsulated beautifully in the title of her recently published paper: “Inferring the Popularity of an Opinion From Its Familiarity: A Repetitive Voice Can Sound Like a Chorus”. The article appears in the Journal of Personality and Social Psychology.

Makes you think, doesn’t it, about the whole tricky field of public consultation, hijacked with tiresome regularity by special interest groups. Just a small number of coordinated calls to a politician, Dr Weaver argues, could lead to that politician believing that an opinion is more widespread than it is.

Now think of religiously motivated, anti-science lobby groups, animal rights extremists, climate-change deniers. Through repetition, their dangerous whispers carry farther than their small constituencies merit, sometimes awarding them a disproportionate influence over public policy. We should not close our ears but we should remember that such groups do not speak for all.

Why did the chicken cross the road? Because it had an inbuilt compass guiding it to the other side of the thoroughfare. Scientists at Frankfurt University set out to test whether chickens, like migrating birds, possess an internal magnetic compass. They trained newly-hatched chicks to regard a red ball as their mother (don’t ask). The ball was hidden behind one of four screens, always the northerly one, and the chicks learnt to find it.

The researchers then created an artificial magnetic field pointing east; the chicks started searching behind the easterly screen. This, according to a paper in the Journal of Experimental Biology, proves that domestic chickens are indeed steered

College, London, whom I met at the Royal Society’s summer party last week. “Some people decide to give up learning and become an authority,” he said, lamenting older scientists who stifle new ideas to protect their own interests. Professor Nelder is 82. And an example to us all.

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