A third study in five months has found disturbing responses from the American public to scientific questions. Rather than testing factual knowledge, this survey framed questions in terms of five levels of confidence in various scientific conclusions. In the process it revealed the influence of political and religious controversy even more starkly.

Only 6% of those polled by Associated Press-GfK doubted that mental illness is a medical condition, and 8% questioned whether our cells contain genetic code. Presumably this is a reflection of the fact that there are no significant lobby groups spreading disinformation on these topics. An even lower figure, just 4%, doubted that smoking causes cancer, perhaps because the tobacco industry has focused its efforts on disputing the effects of passive smoking , and the addictive nature of nicotine , rather than the challenging the smoking-cancer link outright.

More encouragingly still, only 1-2% described themselves as “not confident at all” on these points. Most of the doubting minority put themselves in the “not too confident category”. The greatest confidence was expressed in regard to smoking, with 59% calling themselves “Extremely confident” of the link to cancer, 23% very confident and 12% somewhat confident. The mental illness and genetic code questions attracted more even divisions across the three most confident responses.

However, as Anthony Leiserowitz, director of the Yale Project on Climate Change Communication put it, “the force of concerted campaigns to discredit scientific fact” can be powerful indeed.

A majority, 51% of the 1012 randomly sampled adults, indicated they lack confidence in the Big Bang theory. With the recent death of John Dobson , regarded as the last supporter of the steady state theory with any prominence, it seems a safe bet that doubts about the Big Bang stem from creationist attacks, rather than alternative scientific hypotheses. Only 8% were “extremely confident” that the Big Bang began the universe, while 30% were “not confident at all”.

Nevertheless support for evolution through natural selection (including for human beings) attracted substantially more support than the Big Bang, with 14% in the “extremely confident” camp, although opposition was almost as high at 27%.

The anti-vax lobby can only look at the success of creationists and dream, but with 15% of the population doubting that childhood vaccines are safe and effective they've got enough support to generate dangerous outbreaks

The two statements about the Earth, that it is 4.5 billion years old and that it is warming largely as a result of gasses released by humans, attracted 36% and 37% doubts. In both cases this putting the doubters narrowly ahead of those who expressed the top two levels of confidence. In between, 33% and 28% respectively described themselves as “somewhat confident”.

All the statements, other than one testing religious belief, had been confirmed by Nobel Prize winners as having overwhelming scientific support. Figures quoted are in addition to the 2-4% who failed to answer each question.

While the responses are broadly consistent with those from a study for the National Science Foundation released in February, the use of the five point confidence scale allowed for more subtle insight into public attitudes. For example, while 48% in the NSF study agreed humans had evolved from other animals here we see 14% "extremely confident" of the idea, 17% “very confident” and 24% “somewhat confident”. A survey by the Pew Research Center , on the other hand, revealed that when given a choice between natural selection, “Intelligent Design” and the creation of species in their current form the breakdown was 32%, 24% and 33%.

“Science ignorance is pervasive in our society, and these attitudes are reinforced when some of our leaders are openly antagonistic to established facts,” said Randy Schekman of the University of California, Berkeley winner of last year's Nobel Prize in medicine.

Alan Leshner CEO of the American Association for the Advancement of Science ruefully noted that, “Most often values and beliefs trump science.”

Unsurprisingly, doubts about the science rose with affiliation to hostile groups. People who described having faith in a supreme being were less likely to accept the evidence on the Big Bang and the Age of the Earth. Republicans were more doubting of Climate Change. There was also some cross-over. Despite the support of some prominent religious figures for climate mitigation those who believe in God are also less likely to think that humans are changing the climate. Equally Democrats, even religious ones, are more pro-science on the Big Bang and the age of the Earth.