This article originally appeared in The Skeptic, Volume 15, Issue 4, from 2002.
I have always had great difficulty in understanding why so many otherwise rational and reasonable people have beliefs in aspects of the paranormal. Even more difficult for me is understanding the fact that some of my fellow scientists are also capable of embracing zany paranormal beliefs ranging from faith healing through astrology and clairvoyance to close encounters of the third kind. They maintain these beliefs despite their years of training in the scientific method and their professional activity in which (one hopes) they draw logical conclusions from the results of well-designed experiments.
I feel equally perplexed when I discover that scientists whom I admire have strong (and in my view irrational) religious beliefs. I can perhaps make an exception for believers in ‘God the Utterly Indifferent’ but otherwise, the incorporation of firm beliefs extracted from ancient scriptures into the same brain that handles quantum mechanics or molecular biology surpasses my ability to understand human behaviour.
Or perhaps I should say “did surpass my ability to understand human behaviour” as some recent research has shed some light on the differences between believers and sceptics and indicates that a tendency towards scepticism may just be a question of brain chemistry – sceptics (and believers) may be born rather than made.
Neurologist Peter Brugger and his colleagues at the University Hospital in Zurich carried out experiments on 20 self-confessed sceptics and 20 believers in which they asked the participants to distinguish between real faces and scrambled-up ones as the images fleetingly appeared on a screen. A second experiment involved distinguishing between real words and nonsense words which also briefly appeared in front of them.
The participants then took the drug L-dopa which is normally used in the treatment of Parkinson’s disease and works by increasing levels of dopamine in the brain. Under the influence of the drug, both sceptics and believers became less accurate in their identification of real words and faces but, intriguingly, the sceptics became more likely to interpret scrambled words or faces as the real thing.
Brugger concludes from this that “dopamine seems to help people see patterns”, and suggests that paranormal beliefs are associated with high levels of dopamine in the brain. By increasing dopamine levels in sceptics they become more likely to believe in irrational things. For the believers, though, the drug did not significantly increase their pattern-making tendencies, perhaps indicating that there is a plateau effect such that, above a certain concentration, additional dopamine has no further effect.
Dopamine is an important neurotransmitter which, when present in normal quantities, facilitates important brain functions; however, imbalanced dopamine activity may result in brain dysfunction. For more than 30 years the effect of dopamine has been an important area of medical research and, in particular, scientists have studied the connections between dopamine levels and two major illnesses of the central nervous system: schizophrenia and Parkinson’s disease. Somewhat more recently, research has also indicated that dopamine neurotransmission plays a role in drug and alcohol abuse. Knowledge gleaned from this research may lead to new treatments in which dopaminergic drugs are used to affect a variety of behaviours.
I find all of this is slightly disturbing for a number of reasons. For instance, does the research imply that sceptics have abnormally low levels of dopamine and that scepticism is, therefore, some kind of brain dysfunction? Or is it that believers have abnormally high levels of dopamine and it is they whose brains are dysfunctional (to me a much more acceptable hypothesis!).
On perhaps a more serious note, if scepticism is associated with lower than ‘normal’ levels of dopamine neurotransmission (and I’m not sure that one can draw this conclusion from the research findings), does this mean that sceptics may have a greater tendency towards diseases of the central nervous system than believers? Or for that matter, are sceptics more likely to suffer from problems with drug and alcohol dependency?
I seem to remember, from some time ago, a study that indicated that church-goers (in the US I think) had, in general, better health and better life-expectancies than non-church-goers but I don’t think the study contained information on the type of ailments likely to be suffered by both groups. Could this also be linked to dopamine levels, I wonder?
So the next time that you are cornered in a pub by someone who has regular conversations with aliens or who wants to discuss his latest design for a perpetual motion, antigravity machine I suggest that rather than take it with a pinch of salt, you try a pinch of L-dopa.
