Field of Science

The inheritance of religion

An earlier post looked at the connection in the USA between religion and a high teen pregnancy rate. High fertility and religion often goes together, and whenever this topic comes up the immediate question is: will the religious inexorably 'out-breed' the nonreligious?

The answer to that rather depends on how religion (or lack of it) is transmitted through the generations. Luckily enough, there's just been a very nice study on this by Vern Bengston, Professor of Sociology at the University of Southern California.

Bengston and colleagues analysed data from the Longitudinal Study of Generations, which has been following over 3000 Californians for over 30 years. They now have over 4 generations in their database.

In 1971, the first year of the study, they surveyed three generations: grandparents (generation 1), parents (generation 2), and children (generation 3). In the paper, they also looked at data from 2000, by which time generation 2 had become grandparents, generation 3 had become parents, and a new generation, generation 4, had arrived on the scene (generation1 seem to have disappeared !).

Over that time, religious affiliation plummeted. In 1971, only 5% of generation 2 (parents) said they were unaffiliated. By 2000, 33% of this same generation were unaffiliated. In generation 4, the non-affiliated rate was 37%.

But what about religious beliefs? In each survey, they asked people how religoius they were (on a 1-4 scale), and also a number of questions related to how traditional/literal their religious views were.

The results are shown in the first figure. The symbols on the left represent the various generations in 1971, and on the right the generations in 2000. Lines connect generations that appear in both surveys.

On the whole, people who were surveyed both times haven't changed much. Mothers and fathers in 1971 are less religious in 2000, and daughters (but less so sons) are more religious.

But the major difference is generational. Grandparents in 2000 are less religious than grandparents in 1971. Parents now are less religious than parents then. And the new generation (generation 4) is least religious of all.

Now, they don't give any information on how many children the religious participants had compared with the non-religious, but it's probably safe to assume that they had more.

So, with each generation, the religious have more offspring. And yet their numbers decrease!

This paradox is, of course, easily explained. Although there is a small genetic component that predisposes to agnosticism and atheism, they are in fact social phenomena. Irreligion is not inherited. It's learned.

This can be seen most clearly with conservative religious beliefs. Twin studies consistently show that this is the component of religion with the largest genetic component. What's more, conservative Christians have the highest birth rates. Even so, conservative religious beliefs have collapsed with the passing of older generations.

Religion, even conservative religion, is not a gene to be inherited. It's a meme to be transmitted.

The study had another tidbit of information, and that's about how much influence grandparents have over their grandchildren's religiosity. The answer: not a lot.

What we're looking at in this graph is the correlation between the religion of the grandparents and that of the grandchildren, after adjusting for the religion of the parents. So this is the direct effect of grandparents, not the indirect effect (via their children and then on to their grandchildren).

In 2000, grandmothers had a little bit of influence over the religion of their granddaughters. That was particularly true for conservative religious beliefs.

But nobody listened to their grandfathers, and grandsons didn't pay much attention to their grandmothers.

What's surprising is how this has changed from 1971. I haven't done a graph for these data, but basically in 1971 grandparents influenced their grandchildren's church attendance, but less so their beliefs - and they had absolutely no effect over their conservative religious beliefs.

In other words the role of grandparents in transmitting religion has changed completely in the past 30 years - more evidence that the nature of religion in society is changing.

But there's a bigger message here, and that's the magnitude of the influence. Even when it comes to grandmothers and their granddaughter's religiousness, the strongest link, the effect is very weak.

And what this means is that the transmission of religion can be very rapid. The world of our grandparents is already ancient history - at least as far as attitudes and beliefs go.
Bengtson, V., Copen, C., Putney, N., & Silverstein, M. (2009). A Longitudinal Study of the Intergenerational Transmission of Religion International Sociology, 24 (3), 325-345 DOI: 10.1177/0268580909102911

Creative Commons License This article by Tom Rees was first published on Epiphenom. It is licensed under Creative Commons.

The doctors who hasten death

This Fridays' Guardian reports on a new survey which found that a third of doctors in the UK have taken treatment decisions they thought would hasten a patient's death.

The sorts of patients we're talking about here are those who are already near death. Doctors either give doses of pain killers that are high enough to risk causing death, or they withhold treatment that could prolong life.

Around 30% of the doctors surveyed said they had done this at some stage with the expectation that it would cause premature death. Another 7% said that they had done this with the intention of actually causing death. Here's an example, given in the paper, of withholding treatment with the intention of bringing about an early death:

A doctor working in a critical care unit reported on the care of a woman in her 60s who died in hospital of pneumonia, associated with breast cancer. A decision was made not to use artificial ventilation and various treatments, including oxygen,
renal replacements and cardiac inotropes (drugs that affect the strength of heart contractions) were withdrawn. Morphine was given, with a strong increase on the day of death, and a benzodiazepine.

The withholding and withdrawing of treatments were done with ‘the explicit intention’ of hastening the end of life, and the medications given were considered probable or certain to contribute to hastening the end of life. These actions were felt to have shortened life by less than 24 hours.

The reasons given for the withdrawal of therapies included the fact that the patient had pain, other symptoms, had no chance of improvement, that further treatment would have been futile and would have increased her suffering, and that the patient and relatives had asked for this. The decision was discussed with the patient and the discussion included the likely effect on length of life. Discussions with medical colleagues, nursing staff and relatives were also reported.

The patient had made a clear request for the end of her life to be hastened as had relatives and nursing staff. A GP, a specialist in pain relief, and a spiritual caregiver, as well as nurses and relatives had been involved in her care in the last month of life. The doctor had mixed views about euthanasia and physician assisted suicide, feeling that euthanasia in the presence of an incurable and painful illness ought to be allowed, but being opposed to physician-assisted suicide or euthanasia where no such illness was present.
Most of the doctors (65%) were neutral about religion, 21% were non-religious, and 14% were religious. I've plotted out the data: as you might expect, the non-religious were much more likely to have prescribed a treatment that they thought might hasten death.

Now, there's no more analysis than that. It wasn't a random sample of physicians - neurologists, palliative medicine and care of the elderly specialists were over sampled. And men were more likely than women to have hastened a patients' death (as well as, presumably, less religious). So we can't be sure that this is an effect caused by religion.

Still, it seems likely given the strong anti-euthanasia position taken by most religious authorities. And it meshes nicely with the fact that religious patients are more likely to request heroic (but futile) end-of-life treatments.

Of course, end-of-life care is a complicated, multi-dimensional problem. However, in my opinion and the opinion of most humanists, prolonging life to the bitter end, regardless of the consequences for patient and family, may not always be the best course.

Prof Seale, who did the survey, agrees. Here's what he concludes:

Doctors who said they were religious or who opposed the legalisation of assisted dying were less likely to report decisions where they expected or intended to hasten the end of life. This may be because sanctity of life is a more pressing concern for these doctors than quality of life and may be a cause for concern if this results in patients with similar needs and preferences receiving different treatment.

Seale C (2009). Hastening death in end-of-life care: A survey of doctors. Social science & medicine (1982) PMID: 19837498

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

The Malthusian time bomb

Here's a study that Razib over at Gene Expression picked up on last month. Basically, it's a very simple regression of religiosity versus teen births in US states.

Importantly, it's an ecological study. That means it's not looking necessarily at whether religious teens get pregnant more often. It's looking at whether states with a lot of religious people also have a disproportionate level of teen births.

At a policy level, that's the interaction that's actually more useful because it includes the unintended consequences (like reduced access to contraception, changed attitudes towards female roles, etc).

Anyway, the correlation is dramatic. States with a highest numbers of religious people have three times the teen birth rate.

What could be the cause of this? Well, there could be confounding factors. The researchers did adjust for differences in income and abortion rates between states, and that did not have much effect. Razib points out that religious states also have a high proportion of blacks. No doubt there are other systematic differences that could account for the relationship, at least in statistical terms.

But this correlation is very strong, and it does fit in with other evidence that religion can encourage high fertility. Conservative protestants not only have more children, they have them earlier. The social expectations for young women are different.

And it seems to be the beliefs themselves that are important, rather than social aspects of religion. The average level of religious service attendance was not a strong predictor of teen birth rate. The strongest predictor was beliefs - especially beliefs that scripture should be taken literally and that prayers are likely to be answered.

That's not to say that Protestantism necessarily leads to a high birth rate. New research shows that, in Switzerland at the turn of the 18th/19th century, it was Protestants who had low birth rates, and Catholics who had high birth rates. The author, Anne-Fran├žoise Praz (University of Geneva) explains that, in the Catholic canton she studied:

...the religious discourse supported the husband's rights to frequent sexual intercourse and encouraged him to trust Providence to bring up many children, thus sustaining high levels of fertility. The political repression of public discourse on sexuality defeated every attempt of contesting the husband's marital rights and the Catholic doctrine of procreation. Sexual taboos were particularly severe for women and their total ignorance of sexual matters weakened their bargaining power in fertility decisions.

There clear parallels here with conservative protestantism in the USA. Either Protestantism or Catholicism can cause problems - what matters is whether the religion is conservative (i.e. traditional) or not.

So what's all this got to do with a Malthusian time bomb? Well, population levels are determined not just by fertility rate (number of children per adult) but also by generation time.

Conservative religious groups not only have more children per adult, but they churn out the generations faster. The two effects combine to generate a population explosion (maladaptive, in the case of the modern world).

Strayhorn JM, & Strayhorn JC (2009). Religiosity and teen birth rate in the United States. Reproductive health, 6 PMID: 19761588

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

Now tweeting

As we all know, social media like twitter and Facebook are slowly eroding society as we know it and destroying our children's brains. Now I've brought the end of the world one step closer by setting up a twitter feed and facebook page for this blog!

If you are a twitter or a facebooker, this means that you can get notification of new posts by 'following' the twitter feed or becoming a facebook fan (OK so you already knew that!).

If you're neither of these things, you can still get alerts in all the usual ways, like:

Or, of course, you can pop back here from time to time!

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

When people stop believing in God... they go mental?

Probably the most famous thing that GK Chesterton never said was that:
When people stop believing in God, they don't believe in nothing - they believe in anything.
Even if he never did say those words, the quote clearly strikes a chord with a lot of people. The meme has legs.

But is it true? A lot of people these days are moving away from traditional religions into various kinds of 'New Age' beliefs. Are they really more delusional than the religious - and how do they compare to atheists, for that matter.

This new study comes from Queensland, Australia. They've been following a bunch of kids since they were born in the early 80s. They were 21 years old at the last assessment - which is where these data are from.

Basically, they just asked them two simple questions: "Do you believe in God?" (Yes/No/Unsure), and "Do you believe in a higher power?" (Yes/No/Unsure). This latter group they designated 'New Agers". They also asked them a standard battery of questions about delusional beliefs.

The good news for atheists is that they scored lower for delusional beliefs than either the religious or the New Agers.

The graph up top is not particularly easy to understand! So let me talk you through it. What it shows is the relative probability (compared to atheists) of agreeing with a delusional statement for the religious and the New Agers. The probabilities are more interesting than the raw data because they are adjusted for demographic differences between the two groups (including drug use).

There were 21 statements in the test - I've pulled out all the ones where the religious were significantly worse than the atheists, plus a few more that were interesting.

Overall, the New Agers were more delusional than the Religious. That was particularly true for belief in witchcraft and telepathy (not shown in the graph). But the New Agers were also more likely to think that people are not what they seem, that they are being persecuted, that electrical devices like computers can control their thoughts, and that their thoughts are 'echoed back'.

But the religious, while scoring lower overall than the New Agers (although still worse than the atheists) have their own delusions. It's probably not surprising, given the nature of their religious upbringing (an even mix of Catholics and Protestants, with a smattering of other religions), that they're more likely to believe in an imminent apocalypse and also that they are wretched sinners. Neither of these strike me as particularly healthy beliefs.

Bizarrely enough, however, they also are more likely to think that things in print and on TV have been written especially for them. And, although they score lower than the New Agers, they're more likely than atheists to think that their thoughts are echoed back to them.

What to make of all this? Well, this is yet another cross-sectional study, so causality is hard to pin down. Some of the differences in beliefs (apocalypse, sinning, telepathy, witches) might well be a result of the different teachings.

In other words, if you drop out of organised religion but are suitably delusional, then then you might well switch to a belief in witches or telepathy.

But there probably is also some self selection going on. Religion struggles to be mainstream. If you're too wacky, you may find it hard to fit in - and so end up as part of the 'New Age'. But if you're not wacky enough, you simply transition to atheism.

But what about the two delusions shared by the religious and New Agers? 'Thought echo' is a classic form of auditory hallucination in which you can hear your own thoughts being spoken back to you, either instantaneously or a moment or two later.

Perhaps this is linked to the delusion that make people think the TV announcer is talking specially to them? Perhaps they're hearing their own thoughts in some way? Is this a pointer to a fundamental motivator for religious beliefs?

Fans of Julian Jaynes' The Origin of Consciousness in the Breakdown of the Bicameral Mind will be intrigued! (Thanks to David Holmes for reminding recently me of Jaynes' remarkable book).


ResearchBlogging.orgAird, R., Scott, J., McGrath, J., Najman, J., & Al Mamun, A. (2009). Is the New Age phenomenon connected to delusion-like experiences? Analysis of survey data from Australia. Mental Health, Religion & Culture, 1-17 DOI: 10.1080/13674670903131843

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

The merry-go-round between uncertainty, error detection, and religion

This is a post about psychology, and about the how stress, anxiety and uncertainty might lead people to be more religious - and the consequence of that. What triggered it was a NY Times article featuring a recent study. Here's an excerpt:

Dr. Proulx and Dr. Heine described having 20 college students read an absurd short story based on “The Country Doctor,” by Franz Kafka. The doctor of the title has to make a house call on a boy with a terrible toothache. He makes the journey and finds that the boy has no teeth at all. The horses who have pulled his carriage begin to act up; the boy’s family becomes annoyed; then the doctor discovers the boy has teeth after all. And so on. The story is urgent, vivid and nonsensical — Kafkaesque.

After the story, the students studied a series of 45 strings of 6 to 9 letters, like “X, M, X, R, T, V.” They later took a test on the letter strings, choosing those they thought they had seen before from a list of 60 such strings. In fact the letters were related, in a very subtle way, with some more likely to appear before or after others.

The test is a standard measure of what researchers call implicit learning: knowledge gained without awareness. The students had no idea what patterns their brain was sensing or how well they were performing.

But perform they did. They chose about 30 percent more of the letter strings, and were almost twice as accurate in their choices, than a comparison group of 20 students who had read a different short story, a coherent one.

“The fact that the group who read the absurd story identified more letter strings suggests that they were more motivated to look for patterns than the others,” Dr. Heine said. “And the fact that they were more accurate means, we think, that they’re forming new patterns they wouldn’t be able to form otherwise.”

In other words, when you start to break down people's sense that they understand what's going on, they respond by turning up the 'gain' on pattern detection. Similar things have been seen in previous studies, except in these studies the gain detection is turned up so high that people see things that aren't there at all.

For example, people who are made to feel like they are not in control tend to see patterns that aren't there. And people who are made to feel lonely are more likely to anthropomorphize (i.e. see pets and even gadgets as friends).

The interesting thing is that the NY Times ties this study in with an earlier one by Michael Inzlicht, on how 'error-related negativity' (ERN) predicts academic performance. ERN describes a brain signal that's triggered when you make a mistake.

The idea is that the bigger the ERN signal, the bigger the distress you get from things that don't make sense. Inzlicht showed that people with a big ERN response have better academic performance. They learn better.

The implication is that creating uncertainty increases the ERN, and so improves your ability to detect patterns and learn from mistakes.

Now, what the NY Times didn't pick up on is that Inzlicht published another study earlier this year (I blogged it here). This study showed that religious people have a low ERN.

So uncertainty increases, and religion reduces, ERN. It looks like a feedback mechanism to keep levels of ERN under control by reducing the level of ambiguity and uncertainty in the world (by 'explaining away' mysteries) - at the cost (perhaps) of failing to pick up on real, but obscure patterns.


ResearchBlogging.orgProulx T, & Heine SJ (2009). Connections from Kafka: exposure to meaning threats improves implicit learning of an artificial grammar. Psychological science : a journal of the American Psychological Society / APS, 20 (9), 1125-31 PMID: 19656338

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

Religion and volunteering

The last post was on religion and work ethic. So to follow up here's another new paper on a similar topic: religion and volunteering.

Religious people do more voluntary work than non-religious people. According to a June 2009 Canadian report, the 15% people who go to Church every week make up 26% of the volunteer workforce.

It's difficult to figure out exactly why this should be. Is it spiritual beliefs? The evidence I put up in my previous post, linking religious beliefs to a small increase in work ethic, might make lead you to think so. Religious people get an extra reward from volunteering (they usually believe they'll get some kind of bonus from their God): that makes it more attractive.

But maybe it's cultural. Religious people tend to swim in a sea of 'volunteerism', so volunteering might simply be something that's expected of them by their peers. They also get more opportunities to volunteer, by virtue of being plugged into a ready-made volunteer network.

In contrast, non-religious people might be excluded from volunteering because (especially in a religious society), many opportunities for volunteering come with a lot of religious baggage. That can be a turn-off for the non-religious.

The new study, by Bianca Suanet and colleagues at VU University in the Netherlands, is interesting because it takes a fresh angle on the problem (VU University, by the way, has its historical roots as a Christian university).

They looked at two samples of Dutch people, a set who were around 60 years old in 1992, and a set of people who turned 60 in around 2002. In other words, the second set of people was born 10 years later.

They found that 43% of people who were 60 in 1992 did voluntary work, but this had dropped to 37% of those who were 60 in 2002. A small drop, but statistically significant.

Next they looked at the factors that might explain the drop. Most had no effect: it didn't matter whether they were employed, had a father who was a church member, had a mother who did volunteer work, or had well educated parents.

What did matter is their own level of education - highly educated people were 2.7 times more likely to volunteer than people with low education levels. That might be, of course, because highly educated people tend to also have high levels of self-motivation. But presumably the psychological characteristics of the cohorts were the same, which suggests that it's a direct effect of education on volunteerism.

And the other factor that made a difference was religious involvement. People who had religious beliefs but didn't go to Church were not more likely to volunteer. But people who did go to Church were.

For religious non-Christians and Catholics, the effect was impressive - they were over 2.5 times more likely to volunteer than the non-religious. But for practising Calvinists, the effect was dramatic - they were 4.7 times more likely to volunteer.

Now, the actual effects of religion remain pretty small. Overall, they could explain only 16% of the variation among individuals. And religion is only a fraction of that (it's pretty hard to tell from the stats they present, but it probably explains about 5-10% of the variability). It's small, but it's there.

So in light of this, there's one other fascinating fact that comes out from the study. It turns out that, after controlling for all the other factors (including the increase in their education levels and the loss of religious belief), the more recent set of 'oldies' were actually more likely to be volunteers.

In other words, the decline in religion causes a negative hit on volunteering. That's made up for a bit by the increase in education. But there's something else going on that's increasing volunteering.

And that something may well be cultural. To me, it seems likely that Dutch society is reinventing itself as religion becomes increasingly marginalised. Whereas religion and volunteering were once intimately connected, now volunteering is something for non-believers as well (incidentally, this is reflected in the constitution of VU University itself, which transformed itself in the 1960s from a religious university to a secular, state funded one).

So a secular future may not mean a future without volunteers. And the good news from Canada is that this is probably the case.

Canada, like other Western nations, has seen plummeting religious participation (Statistics Canada). And volunteering went down from 191 hours per person in 1987 to 149 hours in 1997 (here's the 1997 report). But the last report shows an uptick, with volunteer rates climbing to 166 hours in 2007.

I think that the take-home from this is that religion probably does stimulate volunteering. But religion is not the only way to achieve this, and it's probably not the best, either.

Suanet, B., Broese van Groenou, M., & Braam, A. (2009). Changes in volunteering among young old in the Netherlands between 1992 and 2002: the impact of religion, age-norms, and intergenerational transmission European Journal of Ageing, 6 (3), 157-165 DOI: 10.1007/s10433-009-0119-7

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

The Protestant 'Work-Shy' Ethic?

At the start of the 20th Century, the sociologist Max Weber came up with a famous theory to explain why Northern Europe and North America were so prosperous: the Protestant Work Ethic.

Basically, the idea was that a unique feature of Protestant Christianity is its emphasis on work as a duty to God. While other religions asked people to do things that were laborious and time consuming, only Protestantism (so the theory went) channelled that religious duty into productive work.

It's important to take some time out here to understand what's meant by 'work ethic'. It certainly isn't simply productivity. The richest, most productive countries actually have the lowest work ethic.

And a lack of 'work ethic' doesn't mean you're lazy or driven only by financial reward. In fact, educated people have a lower 'work ethic' than uneducated people. Clearly educated people aren't lazy - they work hard to get their qualifications and don't get paid to do it.

So 'work ethic' is actually about working for no clear purpose - it's work for work's sake.

Well, in the 100 years since there's been a lot of debate and no clear conclusion about whether Weber was right. But, in theory, it seems plausible. According to economists, people only do work if they are going to get some kind of reward. If you can convince them them that their reward will be 'magical' (some kind of spiritual reward in this life or the next) then you won't have to pay them as much.

In modern economic terms, a Protestant would gain extra 'utility' from doing work, and so they would have additional motivation to work harder.

But even if the idea did hold in the past, does it still work in the modern world? And if it does, how does it work in practice? A new paper by Hans Geser has taken a look.

He scrutinized data from the Christians in the World Values Survey and found that, as far as work ethic goes, Protestantism probably isn't very much different from Catholicism and Orthodox Christianity.

But he did find some interesting relationships with religion in general. Basically, people with stronger religious faith have a stronger work ethic. But other factors of religion - whether people took Church teaching seriously, whether they went to Church, or whether they prayed - seemed to have little or no effect.

There was a surprise, however. Belief in an afterlife actually had a negative effect on work ethic.

The effect of religion was small. Overall, only around 5% of the variation between people in work ethic is explained by religion. But Geser's analysis suggests that it's not due to religious teachings. And the promise of a reward in heaven actually has a negative effect.

Which suggests that the reason religious people have a higher work ethic is that they expect to get a reward for it in this life, rather than the next.

One last thing. The effect of religion, which is small even in poor countries, disappears in rich countries. That's not because the effects at an individual level get less. What happens is that the 'national average' intensity of religious faith has a cultural effect - increasing the work ethic of believers and non-believers.

As countries get richer, their culture shifts from a religious to a secular one. And with that, the idea of working for the sake of work becomes marginalised. In rich countries, people work because they see a reason to do the work.

Hans Geser (2009). Work Values and Christian Religiosity: An Ambiguous Multidimensional Relationship Journal of Religion and Society, 11 (24)

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

Brain patterns of belief

Sam Harris, author of The End of Faith, has just published a second brain imaging study of religious belief.

Harris and his colleagues were interested in two questions. Firstly, how does the brain process ideas of 'belief' and 'disbelief' - and does it differ when you are talking about religious beliefs or other kinds of beliefs.

Secondly, which bits of the brain evaluate religious beliefs, and do they differ from the evaluation of non-religious beliefs.

It was the usual neuroimaging deal: take some committed believers, and some committed non-believers, and fire some questions at them while scanning them. Broadly speaking, you put the subjects in two different mental states, and then subtract one from the other.

The difference between the two is what shows up in the orange in the picture on the right. Those are the bits of the brain that are more active in one mental state relative to the other.

What they found was that different bits of the brain light up when you evaluate a statement that you believe to be true compared with one that you believe to be false. And it really doesn't matter whether you are a believer or a non-believer, or whether the statement is a religious one or a non-religious one.

What matters is whether you, personally, believe it to be true or false. In other words, there does seem to be anything special about religion here. A believer will evaluate a religious claim that "The God of the Bible is literally true" in the same way that non-believer will evaluate the statement "The biblical god is a myth". And they will both evaluate these in the same way as the statement "Santa Claus does not exist".

But where the study did find a difference was for religious claims in general (whether or not they were believed to be true). That's what the image at the top of this post shows. It's the parts of the brains that light up when processing a religious claim, compared with a non-religious claim.

So what does this prove? Well, part of the problem with these kinds of studies is that it doesn't show much. The brain's a complex, poorly understood organ, and each bit of the brain has been linked to several different functions.

With that caveat, Harris reckons that evaluation of religious statements seem to be linked to emotions of disgust and pain:

The contrast of religious stimuli minus nonreligious stimuli (see Fig. 2A, Table 3.) revealed greater signal in many regions, including the anterior insula and the ventral striatum. The anterior insula has been regularly linked to pain perception [34] and even to the perception of pain in others [35]. This region is also widely believed to mediate negatively valenced feelings like disgust [36], [37].

On the other hand, non-religious statements are linked to regions of the brain connected with memory and semantic evaluation:

The opposite contrast, nonreligious minus religious statements, produced greater signal in left hemisphere networks, including the hippocampus, the parahippocampal gyrus, middle temporal gyrus, temporal pole, and retrosplenial cortex (see Fig. 2B, Table 4). It is well known that the hippocampus and the parahippocampal gyrus are involved in memory retrieval [42]. The anterior temporal lobe is also engaged by semantic memory tasks [43]

If that's the case, then it would seem to support the idea that non-religious claims are decided by a logical evaluation, whereas religious claims are decided according to whether they disgust you or not.

And a last little titbit. There was also a difference in how quickly the subjects evaluated the statements. The quickest response times were for the non-believers when evaluating religious claims they agreed with (i.e. "The biblical god is a myth"). In general, it's quicker to evaluate a 'true' statement than a false one. Could it be that 'Religion is false' is more true for nonbelievers that 'Religion is true' is for believers?

Harris S, Kaplan JT, Curiel A, Bookheimer SY, Iacoboni M, & Cohen MS (2009). The neural correlates of religious and nonreligious belief. PloS one, 4 (10) PMID: 19794914

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.

How to spot them in the wild: visual characteristics of religious v nonreligious

There was a study in the New Scientist earlier this year linking what people look like with their personality (I blogged it a few weeks ago). It turned out that it was possible to spot the religious women in the sample from their faces alone.

Now interpreting this was a little tricky, because the non-religious 'typical face' was smiling, and the religious one wasn't. Which suggests that, in the UK at least, you can spot religious people because they don't smile.

But here's a new study, from the US this time, that gives a radically different slant. Laura Naumann (UCB) and colleagues got a group of students and took whole-body (clothed!) photographs, first unposed and then after asking hem to stand in a standard pose.

They also assessed personality by asking the subjects to rate their own personality and also asking them to nominate three friends to rate them. This is the 'gold standard' of personality assessment – because often your friends are a better judge of your personality than you are.

The also asked them whether they were religious, and their political orientation.

Then they asked a second group of students to assess the subjects personality based on photos alone. Basically, individuals are pretty poor at judging personality. In the standardized pose, they were just about able to pick up on extraversion. In the unstandardized pose, there was a hint towards being able to spot the religious.

Things got better when the researchers took a 'wisdom of crowds' approach. This uses a kind of democratic approach, averaging the individual estimates to see what the consensus opinion is. The crowd was able to pick out a religious person just over 60% of the time (you'd expect 50% by chance alone). It was a little bit easier to spot them in the unposed photos, but not much (62% vs 64% - small, but statistically significant).

So, it seems that there is something about how the religious people looked that enabled the raters to pick them out. So the question is, what was that?

Well, the researchers marked all the photos according to several criteria, and rated these against personality. On average, the religious people were more likely to be energetic, relaxed and, importantly, smiling.

Yes, that's right, in this sample of US students, you can pick out the religious because they're smiling. In the UK sample (of New Scientist readers) they were less likely to be smiling.

What's happening here? It could be an age effect, or it could be the different social status of religion in the USA and the UK. To be part of the mainstream in the USA means to be religious, whereas the opposite applies in the UK (for most people in the UK, religion is unimportant, even if they aren't exactly atheists).

In the US, unlike the UK, being non-religious is linked to social exclusion.

It's interesting to compare the characteristics of religious people in the sample with popular people. They're pretty similar. You can see from the graph that, like religious people, people with high self-esteem or who are likeable are more likely to smile and to look energetic and relaxed.

Unlike popular people, though, religious people aren't more likely to look healthy, ordinary, or stand with their arms behind their backs. I'm not too sure what to make of these differences!

Here's another interesting nugget from the study. The first graph show the actual, objective characteristics that are linked to religion and other traits. But their data also let them assess the extent to which their raters used these characteristics as cues.

In other words they could compare what their observers thought characterized religious people, with what actually did. The results are shown in the second graph.

The first thing to note is that the 'What people think' bar tends to be longer than the 'Actual' bar. What this means is that people think it's easier to spot religious people than it actually is.

The other interesting thing is the discrepancies. The raters thought they could pick out the religious people by picking those who were healthy, ordinary and, most especially neat. But in fact the religious people weren't really any of these things.

The curious thing is that the raters didn't expect religious people to look relaxed. Whereas, in fact, looking relaxed was a key attribute of the religious.

So there you have it. They expected religious people to be neat, but in fact they were relaxed! Why should this be? I suspect it's simply because the raters didn't realise that, in their community, religious people are simply the popular people.

Naumann LP, Vazire S, Rentfrow PJ, & Gosling SD (2009). Personality Judgments Based on Physical Appearance. Personality and social psychology bulletin PMID: 19762717

Creative Commons LicenseThis work by Tom Rees is licensed under a Creative Commons Attribution-Share Alike 2.0 UK: England & Wales License.