In one of his recent “Bad Science” columns in the Guardian newspaper, Dr. Ben Goldacre, the British physician, writer and relentless scourge of all forms of medical quackery, discusses the perplexing and persistent problem of why people either ignore or rationalize away scientific evidence that challenges their pre-existing views.
Writes Goldacre (with British spellings intact):
The classic paper on the last of those strategies [rationalizing away the evidence] is from Lord, Ross and Lepper in 1979: they took two groups of people, one in favour of the death penalty, the other against it, and then presented each with a piece of scientific evidence that supported their pre-existing view, and a piece that challenged it; murder rates went up or down, for example, after the abolition of capital punishment in a state.
The results were as you might imagine. Each group found extensive methodological holes in the evidence they disagreed with, but ignored the very same holes in the evidence that reinforced their views.
Some people go even further than this, when presented with unwelcome data, and decide that science itself is broken. Politicians will cheerfully explain that the scientific method simply cannot be used to determine the outcomes of a drugs policy. Alternative therapists will explain that their pill is special, among all pills, and you simply cannot find out if it works by using a trial.
To support this point — that we are willing to throw in the entire scientific towel, so to speak, just because we found one set of data not to our liking — Goldacre describes a study published earlier this year in the Journal of Applied Social Psychology.
In that study, people were asked to read the abstracts of five fake (although the participants didn’t know that) research papers that either confirmed or contradicted their pre-existing view that homosexuality is or is not associated with mental illness. (For the record: Homosexuality is not associated with mental illness.) Afterward, the participants were asked to use a nine-point scale to rate how much they agreed or disagreed with the statement that “[t]he question addressed in the studies summarized … is one that cannot be answered using scientific methods.”
Those people who read abstracts that challenged their pre-existing view on homosexuality and mental illness (no matter which view it was) tended to agree more strongly with the statement. They averaged 6.1 in their endorsement of the statement compared to 3.61 for the group that had read abstracts confirming their pre-existing view.
Given the earlier research in this area, that’s not all that surprising. But the study went further. Participants were also asked whether they believed science could resolve questions regarding other topics — “the existence of clairvoyance,” “the effectiveness of spanking as a disciplinary technique for children,” “the effect of viewing television violence on violent behavior,” “the accuracy of astrology in predicting personality traits” and “the mental and physical health effects of herbal medications.”
[T]he results were truly frightening. People whose pre-existing stereotypes about homosexuality had been challenged by the scientific evidence presented to them were more inclined to believe that science had nothing to offer, on any question, not just on homosexuality, when compared with people whose views on homosexuality had been reinforced.
When presented with unwelcome scientific evidence, it seems, in a desperate attempt to retain some consistency in their world view, people would rather conclude that science in general is broken. This is an interesting finding. But I’m not sure it makes me very happy.
That finding shouldn’t make any of us happy.