Does science affect people’s beliefs? For good or ill?

The fundamental belief underlying this blog is that the truth matters, and that science is the best hope we have of approaching a true understanding of health and disease. I make an effort to investigate and understand the scientific evidence behind veterinary medical approaches and then communicate those findings to my clients and the public because I believe that this is the best way to make the right healthcare decisions for our pets and to avoid the harm and waste of  time, effort, and resources involved in utilizing approaches that don’t work. While I am a realist, and I understand that no amount of objective evidence can change the beliefs of someone with a deep faith in a particular approach or a compelling personal experience that is contrary to the rational, scientific conclusions about it, I still hope that information will truly be power for veterinarians and pet owners, and that we can learn to compensate for our biases and cognitive blind spots and make better, informed decisions.

I do, however, have my doubts. Most polls show that Americans trust scientists more than politicians, but really what does that prove? I trust chiropractors more than, say, the government of Iran, but that doesn’t mean my faith in chiropractors is all that deep. And while polls show most Americans believe science has made life better, most Americans also can’t distinguish between legitimate science and pseudoscience. Purveyors of bogus medical therapies can take advantage of the public’s trust in science easily by simply borrowing or manufacturing jargon than gives the impression of scientific credentials regardless of the real evidence for or against their snake oils. The media can easily manufacture “scientific controversies,” such as those between evolution and intelligent design or between proponents and opponents of the concept of anthropogenic global warming, simply by present on an equal footing two “experts” with differing opinions, regardless of the underlying difference in plausibility or evidence behind these opinions.  So while people trust science to some extent, this is a poor safeguard against the unscientific.

And as a culture, we are deeply faith driven. The overwhelming majority of Americans believe in God, and a solid majority believe God and other spiritual powers are active in daily life, affecting health and disease among other things (for example). So the habit of believing in what cannot be scientifically evaluated is natural to many of us. This makes it difficult to convince people that the scientific evidence against a particular medical therapy should outweigh the personal convictions or testimonials of believers in it, which are generally viewed as at least as good, perhaps better a form of evidence than that provided by science.

A friend recently passed along a social psychology study which, while not definitive by any stretch, does suggest that the picture is even bleaker than this, and that the conclusions of scientists may actually influence people to believe even more strongly in something science demonstrates is not true. The study is called Social influences on paranormal belief: Popular versus scientific support (Curr Res in Soc Psych 2009;15(3)).

Briefly, the investigators gave subjects (the usual undergraduate volunteers) some information about the popular belief and scientific consensus concerning ESP according to four conditions:

Condition 1: Participants read that 25% of the American public believes in ESP and that the scientific community rejects the possibility of ESP.

Condition 2: Participants read that over 90% of the American public believes in ESP and that the scientific community rejects the possibility of ESP.

Condition 3: Participants read that 25% of the American public believes in ESP and that the scientific community is becoming more open to the possibility of ESP.

Conditions 4: Participants read that 90% of the American public believes in ESP and that the scientific community becoming more open to the possibility of ESP.

The subjects then watched a video of a person supposedly demonstrating ESP by guessing the suit of playing cards they could not see. In the video, the guesser is actually informed of the suit and so does much better than one would expect by chance, as someone with ESP would be expected to do. The subjects then completed a questionnaire evaluating their belief in ESP and whether the video was a demonstration of ESP powers.

The mean belief scores were as follows:

Condition 1 (25% of public believes; science rejects): 4.58 (SD = 1.92)

Condition 2 (90% of public believes; science rejects): 4.50 (SD = 1.60)

Condition 3 (25% of public believes; science accepts): 3.58 (SD = 1.84)

 Condition 4 (90% of public believes; science accepts): 4.80 (SD = 1.70)

Analysis of these results showed a significant effect of public belief, with subjects being more likely to believe in ESP if told that most people do. Overall, the scientific community opinion on ESP did not affect the subjects’ level of belief, a depressing hint that science doesn’t have as much influence on the acceptance or rejection of an idea as the popularity of the idea does. However, there was a statistically significant effect of scientific consensus on subject’s belief when ESP was described as not commonly accepted. In this condition, people were more likely to accept ESP as real if scientists rejected it, and more likely to reject ESP if scientists accepted it as possible.

These are not particularly strong findings easily applicable to popular tendencies towards accepting or rejecting the scientific view on implausible propositions, and I don’t mean to make too much of them. However, my personal biases are affected by my own experiences, as everyone’s biases are. I am confronted with depressing regularity by the attitude that what everyone believes cannot be wrong regardless of the soundness of the scientific evidence against it. Personal experience and faith seem in most of us to be far stronger influences on belief than scientific evidence, and even the hint that scientific rejection of an idea may be seen as a reason to believe in that idea worries me.

CAM proponents frequently dismiss scientific evidence with ad hominem reasoning, claiming that the ideological biases or financial interests of those promoting science-based medicine make their conclusions untrustworthy. It is almost automatic for those with unconventional beliefs to assume any evidence provided by commercial researchers (such as those in the pharmaceutical or pet food industries) is worthless at best, if not intentionally deceptive. Could we actually get to the point where the same suspicion was widely applied to science in general, and where scientists were assumed to have ideological or more venal biases that invalidated their conclusions on any idea that claimed itself to be outside the purview of science and more properly in the realm of faith and personal experience? Am I wasting my time trying to convince people that intuitive and traditional ways of knowing the truth about health and disease are inferior to scientific ways? Am I actually promoting the very therapies I criticize because mistrust of science and scientists may incline people to decide in favor of those propositions science argues against?

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