Believer Brains Different from Non-Believer Brains?

As mentioned in an earlier blog about my research interests, my general (research) focus relates to issues of mental health (schizophrenic symptoms in particular) and I hope to build my career in that area. A side-interest of mine relates to neuropsychological and neurophysiological effects of religion. I am by no means any kind of expert on the matter nor am I intimately familiar with the breadth of literature that already exists on the subject. I like to briefly explore this issue for my own understandings and sometimes comment on any new findings.

Considering that the neurosciences as a whole are facing a rather misguided onslaught from Creationists (not-so-cleverly disguised members of the Intelligent Design lobby), it is likely that religious issues are likely to be brought oftentimes to the table in more or less the same manner as evolution has been and is being made a meal for the irrational and bloodthirsty.

Now last night I saw an interesting article entitled: "Brain Differences Found Between Believers In God And Non-believers". Doesn't that sound sensational? On the face of it it sounds as if something major has been discovered when the actual fact is that brain differences exist in all of us. Glaringly obvious, it is the reason why we all are different people. The individual differences are what make us unique. It is also the reason why people who suffer traumatic brain injury in similar areas exhibit symptoms that are similar to each other, but also different. Severity of injury is also a factor of course, but everyone's neurological makeup is different and will thus respond differently. So if brain differences are found between religious and non-religious people, is it really that much of a big deal?

Generally I prefer to read the actual papers of these studies and not Internet news articles, because by analysing the methodology and results of experiments it is possible to see whether the conclusions properly interpret the data. You'd be surprised how often they don't, or at least fall into the "correlation implies causation" trap. But before I go on, here's the basic info:

Michael Inzlicht and his colleagues at the University of Toronto carried out two studies (Study 1 = 28 participants, Study 2 = 22 participants, Total n = 50) by enabling participants to complete a Stroop Task while being hooked up to an Electroencephalogram (EEG) machine in order to measure their brainwaves. The Stroop Task is a well-known and frequently used psychological measure to test reaction times. It usually consists of looking at a series of words flashed briefly on a computer screen; by pressing a button (say, 'Enter') and another (say, the space bar) you confirm or deny the colour of the word that is displayed as fast as possible. If RED is displayed, you would press 'Enter' to confirm it, and if BLUE was displayed, you would press the space bar to deny it. As you might expect, this can get quite confusing especially as the task moves quite fast so it is natural to expect errors to be made. In this way it is a good way to measure response times and then analysing the correctness or erroneousness therein in terms of the study's aims.

And as these participants were hooked up to the EEG machine, they were measuring something called the error-related negativity (ERN), which is a waveform that is generated by the anterior cingulate cortex (ACC) of the brain, which is an area usually associated with regulating emotional and cognitive responses. The main difference between the two studies was that in the first, the participants were previously tested for aspects of their personality such as the need for closure, behavioural inhibition and activation, self-esteem and religious zeal; the second tested a different group of participants using a single-item measure of belief in God, an IQ test, as well as a measurement (popularly known as the 'Big 5 Test') of five prominent aspects of personality. The experimental method in both studies was otherwise the same.

To cut a long story short, it turned out that the religious participants in both studies scored a lower spike in terms of getting incorrect answers.

In other words, Inzlicht and his colleagues interpreted their data as saying religious people tend to be less anxious and less prone to error than non-religious people ("religious conviction is associated with reduced neural responsivity to uncertainty and error").

Does this make sense to you? Correlation does not necessarily imply causation. There are a number of reasons why this result could have been obtained. For a start, the authors saw fit to explicitly mention that all the participants were right-handed, which might have affected their response times in pushing buttons. Might left-handed people have fared better? That's just a tiny reason, though, but I notice that the Neurocritic has done a wonderful job of analysing it this study and has related it to an earlier study by Amodio et al. (2007), that tested for brain differences in politically liberal and conservative people. He has noted a disagreement as to what exactly the ERN represents; is it an objective or emotional response to error? Remember, the ACC is involved in mediating both cognitive and emotional responses. And also, since EEG measurements are taken via electrodes attached to the scalp, how can we say for sure if the response really originates from the ACC?

And what if the people just happened to be of relaxed dispositions and generally nice chilled-out people? A total sample size of 50 doesn't fill me with the confidence to extrapolate these results to larger populations. Epiphenom, who has also commented on this Inzlicht study, made note of another study (Santesso & Segalowitz, 2009) assessing ERN responses in teenage boys which found them to be negatively associated with risk-taking behaviours. In other words, low ERN makes you less concerned with outcomes in general. It is also associated with low empathy and the low capacity to learn from mistakes.

This doesn't necessarily mean that low ERN measurements translates to religious people being really a heartless and thick bunch (opinions vary, I know); I know plenty who are kind, caring, sympathetic, loving, and all of that. But it does make me curious as to why this effect of less anxiety/stress is found amongst religious people. I know of studies that appear to support the other end of the spectrum, that religious people tend to be more stressed, more anxious, than non-religious people. Just as this Inzlicht study has it's shortcomings, other studies have theirs' too. And as every study analyses an issue from a specific angle it wouldn't be fair to make generalised and sweeping statements. What this all means is that there are a variety of reasons why both religious and non-religious groups of people experience anxiety and stress, such as genetics and life experiences.

A Twitter friend let me know of Neuralgourmet's report (originally reported in a 2002 New Scientist article) of a study conducted by a Dr. Peter Brugger of University Hospital, Zurich, in which he found that administering doses of L-DOPA to a group of believers and non-believers to increase their brain's dopamine levels resulted in more errors being made than normal on a task that required distinguishing between scrambled and actual facial images. Dopamine is a neurochemical that plays an important role in behaviour, cognition, motivation/reward, sleep, mood, attention, learning, and many other important functions. It cannot cross the blood-brain barrier by itself and cannot directly access the Central Nervous System (CNS), and so L-DOPA is a precursor that is administered to raise dopamine levels to cross that barrier. It is used, for example, in treating Parkinson's Disease. Brugger's research showed that non-believers were more able to distinguish between the two categories of images, but the dopamine levels of believers did not have an effect on their performance. He interpreted the results as suggestive of a connection between religious beliefs and dopamine levels. Given the widespread function of dopamine in the brain, I will leave it up to the reader to decide for themselves how relevant and far-reaching these findings are.

It would be tempting to speculate such things as believers having high levels of dopamine (thus prone to religious belief) and genetics studies may or may not confirm this. But when all extraneous factors are controlled for as far as possible, what this all means for us at the end of the day is that there are a variety of complex and intertwining factors that account for the presence of religion, whether it has an effect on the brain or vice-versa. Perhaps Inzlicht himself has provided an apt way of looking at the issue; in his paper he has brought Marx up to date and termed religion as the "Xanax of the people".

One thing in this study that piqued my interest was the use of the Religious Zeal Scale (McGregor et al., 2008). I didn't realise a scale to measure zeal had been developed! I imagine it should come in handy for some specific studies; some of the questions were: "‘I aspire to live and act according to my religious beliefs," "My religious beliefs are grounded in objective truth," and the wistful "I would support a war that defended my religious beliefs."

Harumph.

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Michael Inzlicht, Ian McGregor, Jacob B. Hirsh, Kyle Nash (2009). Neural Markers of Religious Conviction Psychological Science, 20 (3), 385-392 DOI: 10.1111/j.1467-9280.2009.02305.x