Two feet good...

Along with a big brain, walking upright on two feet has often been taken to be a defining feature of the human line. In this week’s New Scientist I have a feature article on some recent ideas about why, and where, bipedality first arose. The ‘where’ question relates not to which part of the globe walking on two feet got going, but whether it was on the ground or in the trees.

What? Walking in the trees? It might sound counter-intuitive, but some researchers have recently been arguing for just this possibility, based on observations of the locomotor behaviour of orangutans. In the wild, orangutans not only move through the branches suspended by their hands, but occasionally ‘walk’ along branches while stabilising themselves by holding onto braches overhead. This ‘hand-assisted bipedalism’, the suggestion goes, could have been the precursor to bipedality in the human line.

It’s a controversial theory. Many other experts in human evolution argue that the fossil record clearly shows that the earliest humans show features of knuckle-walking ancestry. This, the counter-argument goes, points to a knuckle-walking ancestor of humans, chimps and gorillas: while the latter species retained this trait, the human line evolved a commitment to bipedalism as it increasingly abandoned life in, and among, the trees.

As is so often the case in debates about the course of human evolution, more fossils are needed. It would also be good if researchers could arrive at some sort of consensus about what the existing fossils tell us. I suspect that academic rivalries, and prior theoretical commitments, make this prospect unlikely in the short term. But keep your eyes open.

There is an idea even more provocative than ‘tree-walking’ that I was unable to cover in my New Scientist piece because of space constraints. Aaron Filler, a spinal expert at Harvard University with a fascination with human evolution, has recently proposed that the evolution of bipedality has a much older, and much simpler, origin than previous account allow.

By studying the spines of many living and extinct mammals, including apes, Filer claims to have documented a series of changes leading to the upright spine typical of humans. And some of these are astonishingly old. Filler argues that the lumbar vertebrae of Morotopithecus bishopi, an ancient ape that lived more than 20 million years ago (some 7 million years before the split between orangutans and the other great apes), shows tell-tale signs that its owner was an upright biped.

And for Filler, this has little to do with trees or savannahs. Rather, changes to the spine might have arisen by mutations in ‘homeotic’ genes that orchestrate developmental processes. Small changes to such genes can produce big changes by affecting entire developmental cascades. Filler speculates that an ancient mutation may have produced an individual in a single generation with a lumbar region causing an upright posture – the first bipedal ape. And so orangutan tree-walking is derivative, not innovative. “Bipedalism in the arboreal orangutans is a vestige of their ancestry and not so much a harbinger of the human locomotor style,” says Filler. (Filler has a website based on his book expounding this theory at www.uprightape.net. Filler also has a video describing various forms of primate locomotion online here).

While I’m at it, here’s a cool video of gibbons showing off their arboreal parkour antics (this really needs to be watched with sound, as the mixed in music (Welcome To The Jungle, by Guns'n'Roses) really adds to the film).

Scientific Happenings on the South Coast

Brighton, UK, is playing host to fourth annual science festival between 23 February and 2 March, and there is lots on offer for anyone living in the region and interested in a bit of brain food. You can browse the programme highlights here, and there are more detailed pages for the various events on the left-hand side of the page this links to.

You can catch Rita Carter on multiple personalities, Chris Frith on free will, Oliver Morton on how plants ‘eat the Sun’, Phillip Ball on nature’s patterns, Richard Fortey on life at the Natural History Museum and Marcus du Sautoy on the ubiquity and importance of symmetry, among many other talks and events. All in all, well worth checking out.

Evolution’s Engine

The ongoing wars over the teaching of evolution (particularly in the US) have elevated into public consciousness an unlikely topic: molecular microbiology. Modern day creationists, rebranding themselves as ‘Intelligent Design theorists’, have made sweeping, not to say unfounded, claims about the limits on the power of evolution on the basis of a tiny nanomachine called the bacterial flagellum.

This complex structure, made of about 40 interacting proteins, is essentially an outboard motor that powers bacteria through their watery environment. At the heart of the flagellum is a rotary motor that drives a long, whip-like tail, which propels the bacterium as it spins round. It is a magnificent work of molecular engineering (see below).

For ID theorists, it is more than just awe-inspiring in its complexity and elegance. To them, it speaks of intelligent design. For tactical reasons the nature of this designer is often left unspecified. Yet the context of these claims makes it clear that a notion of a creator, of the kind found in Judaeo-Christian cosmologies, is lurking behind the scenes.

In essence, ID is a resurrection of an idea with an old pedigree: the ‘argument from design’ that the apparent plan and purpose in nature call for divine explanation. The most famous incarnation of this argument was bequeathed to us by English philosopher William Paley in 1802. Paley suggested the following thought experiment. Imagine that, walking across a heath, you stumble upon a pocket watch, and ask yourself “How did this object come into existence?”. A mechanical watch is a complex, highly engineered device, whose interacting parts contribute to the overall purpose of accurately telling the time. It is clearly massively unlikely that the components of the watch achieved their specific forms through natural processes, and then just happened to come together by chance – and then work to serve a useful purpose. No, the existence of watches requires the existence of skilled watchmakers. And by analogy, the wonders of nature reflect the efforts of a thoughtful, intelligent, purposeful creator*.

Of course, for evolutionary biologists there is no cosmic engineer or molecular draftsman drawing up plans as part of some biological hobby. The cumulative power of descent with modification — Darwin’s theory of natural selection, in other words — is the ‘blind watchmaker’ of evolution. No cosmic designer needed, thank you. As such, evolutionary-minded microbiologists, geneticists and molecular biologists have felt the need to step up to the charge that the bacterial flagellum is ‘irreducibly complex’, unevolveable, and in need of an intelligent designer to explain how it can exist.

The topic — explaining functional biological complexity at the molecular level — is, of course, of much broader interest. From a purely academic angle, irrespective of the political campaigning of IDists (or IDiots, as some say), the bacterial flagellum is exactly the sort of system we should be looking at the test and refine ideas about the various mechanisms, and specific routes, by which biological complexity arises.

And this is just what scientists have been doing in recent years. In this week’s New Scientist, I have a feature on what has been found, and what remains unclear, in flagellar research. Scientists do not claim to have wrapped up the story on flagellum evolution. But what is more interesting is the way recent scientific debates about the flagellum highlight the intellectual bankruptcy of ID theory. If you took the ID case seriously, you’d say “OK, the flagellum is irreducibly complex and could not have evolved – done.” You might then move onto the next difficult issue in evolutionary biology, and say the same.

The scientists I spoke with, by contrast, have a rather different epistemological approach. Yes, the evolution of complex molecular machines poses difficult questions, but that’s what makes them interesting and rewarding to study. And it’s not that evolutionists just want to club together to shout, “Look, the flagellum evolved – job done!”. They want to get some real explanatory purchase on the problem.

This concern with actually working out the details inevitably throws up different ideas, which other scientists then critically evaluate. Analyses are criticised, hypotheses scrutinised and conclusions questioned. This is the sign of healthy science in action; it leads to real insights and refined understanding. In short, the evolutionary approach is a genuinely testable theory, and a viable research programme. Falling back on ID, on the other hand, reveals an intellectual lack of nerve. Where evolutionary biologists face up to the mysteries the universe presents, and are prepared to put in the hard work required to crack them, IDists give up on trying to reach any sort of understanding whatsoever.

*’But who created the creator?’, you should rightly ask. We may reasonably suppose that a creator of biological splendour would be as complex and apparently ‘planned and purposeful’ as the biological ‘creations’ we want to explain. If so, the existence of this creator also needs explaining. To side step this in issue reflects an outrageous double standard: that complexity and apparent purposefulness and design in one domain (nature) require explanation – so much so that might even feel compelled to infer a cosmic creator from them — but that in another (creator gods) such features are a given. It’s no better than when someone points out one of our own double standards, and we weakly try to justify the inconsistency between the standards we apply to others and those deployed in our own conduct by saying “But you see, in my case it was different….”

For more on the flagellum, see:
http://www.millerandlevine.com/km/evol/design2/article.html
http://www.pandasthumb.org/archives/2007/04/flagellum_evolu_1.html

Natural-Born Killers?

Lately I’ve been thinking about some of the darker facets of human nature, particularly the human capacity for killing each other. There’s enough going on around the world to justify sinking in to a reflective funk about this persistent and troubling behaviour, from rising gun crime on UK inner-city streets to Darfur Iraq and, more recently, Kenya. But I’ve had another reason for dwelling on the nature of the murderous mind: I have a feature article out this week in Nature on current trends in thinking about evolution, the brain, violence and murder.

As a species we’re built to compete for resources (money, sexual partners, status, power and so on), and from time to time the friction caused by everyone rubbing up against each other ignites an emotional explosion leading to murder. And we very likely have an evolved coalitional psychology that binds ‘us’ against ‘them’ in conflicts with outgroups (be they defined along national, religious or ethnic lines); the sparks created by abrasive groups pushing against each can all too easily set off an all-encompassing conflagration that threatens to burn down whole societies (you can fill in your own historical or contemporary examples here).

It’s not all doom and gloom though. Human history, as revealed by palaeontologists, archaeologists, anthropologists and criminologists, has always been plagued by violence and murderous mayhem, both at the inter-personal, one-on-one level, and also in terms of the death tolls exacted by tribal warfare. Yet on timescales from millennia to decades, things seem to be getting better. A much smaller percentage of the populations of modern democracies meet their end through murder of any kind than has been the case for most of the past 5,000 years (see my Nature article, and Steven Pinker’s essay in The New Republic, for more on this).

On the shorter timescale of decades things also seem to be on the up. For instance, the number of armed conflicts around the world, and the number of people dying in genocidal purges, is also on the decline. The Human Security Brief 2006, published by the Human Security Centre at the University of British Columbia, has documented a number of encouraging trends (though there is still, obviously, much progress to be made):

“Notwithstanding the escalating violence in Iraq and the widening war in Darfur, the new data indicate that from the beginning of 2002 to the end of 2005, the number of armed conflicts being waged around the world shrank 15% from 66 to 56. By far the greatest decline was in sub-Saharan Africa….The steep post-Cold War decline in genocides and other mass slaughters of civilians has continued. In 2005 there was just one ongoing genocide—in Darfur. In 1989 there were 10…The number of military coups and attempted coups fell from 10 in 2004 to just 3 in 2005, continuing an uneven decline from the 1963 high point of 25.” (These positive developments are tempered somewhat, the report notes, by increased international terrorism, and greater targeting of civilians in campaigns of political violence.)

In my Nature article, I try to draw out both the causes of violence and murder, and the reasons why they might on the decline over the long term. These are clearly enormous topics, and one could write a big book – or an entire bookshelf – trying to answer these questions, and still leave something important unsaid. In a 4-page feature, space constraints and the need for a coherent arc through the piece mean something has to give. One topic that I wasn’t able to go into in as much detail as I would’ve liked is the possibility that evolution has sculpted the mind to kill. So I’ll explore that idea in a bit more detail here.

Evolved Killers
Most evolutionary see murder as a by-product of our evolved minds, not as a behaviour that natural selection has sculpted humans to engage in. The business of getting through, and getting ahead in, life invariably brings people into conflict with one another. A colleague’s promotion may come at the expense of our own advancement; a competitor in the sexual market may monopolise the attention and affections of those we desire to have as our own; or a rival in the race for power, status and wealth may stand in the way of our goals. The risk that competition over material resources and reputation (which often serves to enhance the attainment of desirable resources) will escalate into murderous violence is particularly acute among men, who in common with many animal species have both more to gain and lose in the in the evolutionary game of successfully reproducing — and therefore greater incentives to place bigger, and riskier, bets at life’s table (essentially, the variance in reproductive output is greater among men than women, so that some men do really badly and others really well, whereas most women cluster around a similar average success) .

On the by-product account, the majority of murders happen when the normal brakes on aggression (fear of retaliation, empathy, and behavioural inhibition) are weak or temporarily overwhelmed by the momentum of an aggressive impulse: after a couple of beers, two hot-heads in a bar start trading insults over pool game, start fighting, take it to the parking lot, and one gets hit, falls, and smashes his head on a curb stone and dies.

And this failure to apply brakes on our aggression can also pose a threat to our supposedly nearest and dearest. Evolutionary psychologists Martin Daly and Margo Wilson of McMaster University, Ontario, Canada, have argued that men frequently use aggression and violence to control and coerce women, which perhaps surprisingly puts them on the same page as many feminists thoroughly antagonistic to evolutionary explanations of relations between the sexes. Occasionally, Daly and Wilson suggest, physical attempts by men to threaten, intimidate and punish their spouses (perhaps to make them think twice before leaving them for another man) occasionally result in “tragic slips” that leave the women dead.

Against this mainstream evolutionary account of homicide as a by-product of psychological mechanisms designed to facilitate completion and control of other people, David Buss, of the University of Texas at Austin, and Joshua Duntley, of the Richard Stockton College of New Jersey in Pomona, have developed a much more ‘adaptationist’ argument [1-3]. According to their controversial homicide adaptation theory, natural selection has fashioned psychological mechanisms to produce homicidal behaviour in a wide range of contexts, and for a correspondingly diverse array of reasons.

Buss and Duntley are critical of approaches to violence that treat it as a singular phenomenon explicable by a single cause — a tendency toward competiveness and risk-taking, or a lack of emotional control and behavioural inhibition, say. The by-product account, contend Buss and Duntley, is too vague, too broad-brush, to be up to the task of explaining the myriad manifestations of murder. Instead, they argue that homicide – the killing of one person by another — covers a range of diverse behaviours, including infanticide, step-child killing, intrasexual rivalry homicides, mate killing, and warfare killing; and their homicide adaptation theory suggests that there is a cold, evolutionary logic to these diverse forms of murder.

Men, for instance, can eliminate a potential sexual rival, acquire his resources, gain access to his mate, ascend a status hierarchy, and send out a message about their readiness to use violence in defence their family and property through murder. Women can use killing to protect themselves against a violently overbearing spouse, or a threatening stalker, as well as eliminating potential mate-poaching females. Natural selection could even favour the killing of biological children in situations when, put in the cold calculus of evolutionary logic, the benefits to investing in the new child are outweighed by the costs, or unlikely to be realised (for instance, if times are tight and other kids are already on the scene, then investing in the newborn might be detrimental to the survival prospects of existing offspring; and if the baby is born deformed or otherwise unlikely to thrive, then further investment— and it is painful to write this — might be the biological equivalent of throwing good money after bad). As Duntley says, “Homicide can be such a beneficial solution to adaptive problems in certain, specific contexts that it would be surprising if selection had not fashioned mechanisms to produce lethal aggression.”

Given the impact and enormity of murder, it is little wonder it looms so large in literature, art and films. It also plays on our minds a worrying amount too, psychologists have found. Building on research by psychologists Doug Kenrick and Virgil Sheets into homicidal fantasies, Duntley and Buss have found that upwards of 90% of men, and more than 80% of women, have had a vivid fantasy about killing someone.

Of course, most people do not act on theses fantasies. And the fact that people fantasise about something does not prove that the act in the fantasy is part of our evolved psychology; many people (mostly teenagers and young men) have fantasised about playing video games, but nobody’s suggesting that gaming is part of human nature. (However, a fascination with pornography is also not something directly selected for over evolutionary time, and there is no evolutionary benefit today for a man to spend time alone with a magazine, or at his computer, rather than getting out and meeting real women; nevertheless, pornography is able to exploit the desire to see naked, sexualised human forms, and the mind has no defence against being tricked and aroused by 2-D images and not just 3-D people in the real world. So it is possible that the predilection so many men have for computer games is explicable by some similar ‘misfiring’ of evolved psychology in a modern context).

At the same time, homicidal fantasies, or ideation, can provide a window onto the murderous mind, just as sexual fantasies illuminate the sexual mind. It is not the existence of these fantasies per se, however, that impresses Buss and Duntley. Rather, it is the pattern of these fantasies. Buss, one of the pioneers of evolutionary psychological studies of human sexuality, draws an analogy with sexual fantasies. Romantic and sexual liaisons are enjoyable, so it is little surprise that fantasies about them preoccupy the minds of both men and women. What’s more interesting is the differences in the types of sexual fantasies that men and women engage in. According to Buss, these map onto the different sexual psychologies that men and women have evolved through eons of sexual selection.

The same holds for homicidal ideation. Not only do the sexes differ in the types of homicidal fantasies they typically entertain; these map onto the different situations in which killing would have been beneficial to men and women over evolutionary time, according to Buss and Duntley. So men frequently fantasise about killing other men who have dissed them or otherwise challenged their social standing (as well as men trying to steal their girl, or men who personally threaten them); women are often moved to homicidal thoughts by abusive boyfriends (although they too report thoughts of killing mate-poachers, a threat to both men and women).

While most people do not act out their homicidal flights of fancy, sometimes they do. Murder does not always result from inflamed passions ignited in the heat of the moment. For example, many men who kill their wives (for cheating on them, say) plan and think through the act before committing it. For Buss and Duntley, this doesn’t make sense according to the standard line in evolutionary psychology that spousal murders typically result from tragic ‘slips’ in men’s attempts to use violence to coerce and control women. On top of this, argue Buss and Duntley, the patterns of homicidal ideation and fantasy correspond to the actual patterns of killings recorded in crime statistics.

For Buss and Duntley, this adds up to some compelling evidence in favour of homicide adaptation theory over by-product accounts. As I mention in the text of the Nature piece, other evolutionary psychologists remain to be convinced. Curiously, evolutionary psychologists are often portrayed as eager to propose evolved functions for all aspects of human behaviour, seeing adaptation and function everywhere they look. Yet the response to homicide adaptation theory shows this is anything but the case. Many think that there is no need to propose separate adaptations for homicide on top of adaptations for aggression as part of the system of competition – murder occurs as a by-product, not as a result of evolutionary design (D&B would counter that this account is woefully under-specified as an explanatory theory of the actual data on homicides).

Even those who remain sceptical about the claims of homicide adaptation theory don’t reject the possibilities of adaptations for murder in principle. As I quote Daly as saying, “I wouldn’t want hitch my wagon to the by-product argument, but I don’t think anyone, including Duntley and Buss, has figured out a good way to identify the hallmarks of homicidal adaptation”. There is also a debate about what counts as an adaptation for killing. Take the case of infanticide. In many species, including langur monkeys and lions, males frequently kill the infants in groups they have recently joined, which eliminates competitor’s offspring and brings females into oestrus so the invading male can have offspring of his own. Anthropological studies have shown that human mothers sometimes kill their own offspring in predictable situations — such as when the baby is deformed or unlikely to thrive, or when current circumstances are poor for raising a child.

It might be objected that in the case of human infanticide, the death of the child usually results from the mother simply walking away, rather than a lethal assault. Unlike in the case of lion infanticide (by males, in this case), the behaviour in human is not routine, and nor does it involve a specific infanticidal act, such as a deadly bite. And while there are likely to be psychological adaptations for assessing the current situation or the prospects for the kid, Martin Daly suggests that this doesn’t require anything that “deserves to be called an infanticidal adaptation – it is a de facto infanticidal act if you just walk away.” Duntley and Buss, for their part, think it’s a mistake to focus on whether death results from neglect or direct action. “We argue is that if there is evolved psychological design that reliably produces the outcome of a dead body, then that is design for homicide,” says Buss.

There are clearly theoretical, empirical and conceptual threads to the debate over whether humans have an evolved psychology to kill in certain contexts and situations. Some people accept the case of adaptations for infanticide; others for the coalitional psychology of war (see Nature article). Not many would go as far as Buss and Duntley in proposing such a wide range of homicidal adaptations. But that’s how science progresses: by people putting forward bold hypotheses, which the scientific community then discusses, evaluates and tests. If homicide adaptation theory can come up with better, more specific predictions, about who should be expected to murder and when — and it claims it does — then we will have to confront the unsettling possibility that we are, in part, evolved killers. On the flip side, this recognition may lead to a better understanding of what drives people to kill, and improved strategies for preventing the frequently senseless loss of life at murderous hands. And that can’t be a bad prospect.

Notes
1. Buss, D. M. The Murderer Next Door: Why The Mind Is Designed To Kill (Penguin, New York, 2005).

2. Duntley, J. D. Adaptations to dangers from humans. In The Handbook of Evolutionary Psychology (ed Buss, D. M.) p224–254 (Wiley, Hoboken, New Jersey, 2005).

3. Duntley, J. D. & Buss, D. M. The plausibility of adaptations for homicide. In The Innate Mind Volume 1: Structure and Contents (eds Carruthers, P., Laurence, S. & Stich, S.) p291–304 (Oxford Univ. Press, Oxford, 2005).

Pride and Preferences – Or How We Live With Our Decisions

No one likes to admit to having made a mistake. Just look at all the politicians and business people who, with a mess on their hands and owing the public or shareholders an explanation, have uttered the famously weak cop out “Mistakes were made” – a rhetorical device that political consultant William Schneider has suggested we call the "past exonerative” tense. While acknowledging an error, the passive voice of the past exonerative distances the speaker from any causal role in their execution.

Realising — and, worse still, publicly admitting — that we have made an error of judgement, a bad call, or acted in a way we are less than proud of is frequently a painful experience. Whether it’s our choice of job, which political party we voted in, the stereo we bought, or how we responded to the homeless guy panhandling at the ATM, most us like to think that we’re intelligent, competent decision-makers and, in general, morally worthy people. When we’re confronted with evidence to the contrary, we feel a mental strain and discomfort that psychologists call cognitive dissonance – two dissonant cognitions, such as “I’m a smart consumer” and “I’ve paid my hard-earned cash for this crappy stereo”, are in conflict, and something has to give. Typically, the preferred cognition is preserved and the other discarded (1).

Since the notion was first put forward some 50 years ago, psychologists have made cognitive dissonance one of the most-studied mental phenomena around. And one thing is abundantly clear from this research: humans are equipped with a variety of dissonance-reducing mechanisms that enable us to live with our decisions, our actions and, ultimately, ourselves.

The study of cognitive dissonance has thrown up some paradoxical results. For example, people tend to prefer an outcome if they endure more hardship, pain or suffering to achieve that end. In one study, participants were more satisfied with a fraternity they joined the harsher the initiation into the fraternity, all else being equal. From the behaviourist perspective dominant when the idea of cognitive dissonance was first mooted, this makes no sense: why should an outcome associated with pain or suffering be deemed more rewarding than one reached through a less unpleasant route?

Seen through the lens of dissonance reduction, however, it makes more sense. As an intelligent, sensible person, we wouldn’t go through a painful or humiliating experience if it wasn’t worth the outcome – in this case joining the fraternity. The dissonance produced by the two cognitions “I am not an idiot who would suffer pointlessly” and “I underwent a severe hazing to join this fraternity” is resolved by declaring the fraternity to be worth joining – and the harsher the hazing, the better the decision (2).

One of the ugliest sides to cognitive dissonance comes to light in the self-serving rhetoric we use to justify prejudices. It is depressingly common that persecuted individuals and groups are dehumanised and made to appear as animals — by being kept cramped and naked and filthy in concentration camps, for instance. The victimisers then respond with disgust at the debased and depraved creatures they have created: “Look at these revolting people! How justified I am in treating them as animals!”.

Yet for all the importance of cognitive dissonance, the precise mechanisms by which we deal with discordant thoughts and feelings, and the ultimate purpose these mechanisms serve, are not well understood. One way to approach these issues to look at the origins and evolutionary roots if dissonance reduction in human children and nonhuman primates. And in a recent study published in Psychological Science, Louisa Egan, Laurie Santos and Paul Bloom have taken just such a comparative, developmental tack to the problem of cognitive dissonance (3).

Egan and colleagues, based at Yale University in Connecticut, devised two tests, one for children, the other for capuchin monkeys, each designed to reveal the reduction of cognitive dissonance in action. The specific kind of cognitive dissonance the authors explored in this study arises when an individual, usually an adult in most studies to date, is forced to choose one item from a set of equally desirable items. Prior to choosing, you have no strong preference for any particular item. Yet being made to choose an item – being forced to create a preference – is discordant with your feelings about the decision you faced. And so after the event, this dissonance is reduced by updating your preferences to reflect the decision you actually made. In the future, the preference generated by the forced choice will stick if the dissonance-reduction machinery has done its job effectively (that is, your new preference is for the selected item, explaining satisfactorily to yourself why you chose it).

In the children’s test, each child had to rate the desirability of animal stickers, which kids seem quite keen on, using a scale of increasingly smiley faces (a few kids were eliminated because they had difficulty with the rating system). The researchers then selected sets of three stickers that a given child had rated as equally desirable, and randomly labelled them as A. B or C. A and B were then presented to the child, who was asked to pick one to take home. Then, the unchosen option was offered up against C: so if A was initially picked out of A and B, then B would subsequently be offered alongside C, and vice versa.

The idea behind this test is as follows. The three stickers in each triad tested were all rated as equally desirable by the child, so there was no preference for one over another. Then the child is made to choose between two stickers of previously equal desirability (A and B). This sets up dissonance between ordinarily selecting things with the greatest utility (the most preferred) and, in this case, making a choice without a preference - dissonance between “Ordinarily picking according to preferences” and “Picking without preferences in this case”. The tension is resolved by unconsciously updating the preference to match the choice actually made, which enhances the perceived value of the chosen sticker and derogates the value of the deselected sticker. So if A is picked first, B is, after the fact, deemed to be a worse choice, thus explaining and justifying the decision just made: “I picked sticker A because sticker B is rubbish”. No dissonance there. Then when B is offered against C (stickers that were previously seen as equals), C will seem relatively more attractive. So when Egan and colleagues saw this pattern of choice, they took this as evidence of cognitive dissonance, and its resolution, in operation.

A similar test was also devised for capuchin monkeys, using M&M sweets of different colours instead of stickers. In addition, because monkeys cannot follow instructions the way a human child can, a different way of measuring preferences had to be used: how quickly they retrieved an M&M of a given colour from a testing chamber. Although the details are more complicated the logic is the same, and after the preferences for 20 different colours of M&M had been established, the capuchins were similarly presented with triads of M&M colours.

Both human children and capuchins showed sign of cognitive dissonance and resolution, as revealed by the pattern of preferences for stickers and M&Ms, respectively: in both cases, there was a greater-than-chance preference for C over the unselected option from the A-or-B choice. This clearly suggests that the basic machinery underlying cognitive dissonance, and the tools for making it disappear, are evolutionary old, and emerge relatively early in development (at the least, they don’t require extensive experience in weighing up preferences and evaluating decisions).

But a perhaps more interesting are the questions these findings raise about the function of reducing cognitive dissonance - just what does it achieve? An early suggestion was that it was simply the response to two competing cognitions, which might lead to mental paralysis if not resolved. Later researchers proposed that mechanisms for reducing cognitive dissonance exist to preserve our self-image as intelligent, competent, morally upstanding people.

Capuchin monkeys do not have a capacity for language, and human children are generally assumed to be cognitively much less sophisticated than adult humans. Yet as Egan et al. point out, their results suggest that either cognitive-dissonance reduction is mechanistically simpler than recent work on the subject has suggested and is not neccesarily related to preserving a complex self-image. The alternative would be to ascribe this sort of self-conception to both capuchins and children.

I think, however, that there’s a third way between the options of whether cognitive-dissonance reduction is mechanistically simple or the protector of a complex self-image - it can be both. One of evolution’s favourite tricks is to take some trait that evolved for one purpose and sculpt it to new ends. This process of co-option or exaptation occurred in the evolution of feathers (initially evolved for thermoregulation, than later exploited for flight); exaptation also enabled a sense of distaste, which is widespread in animals, to evolve in humans into ‘core disgust’ (elicited by bodily products, rotting meat and so on), which seems to have been built on through subsequent biological and cultural evolution into the complex cognitive state of moral disgust (the feeling you get when you think about Hitler, or a child molester, for example (4)).

Something similar might have happened with cognitive dissonance and strategies for its reduction. Rather than choosing between accepting dissonance-reduction as a simple process or accepting a complex inner life of monkeys, and perhaps we should conclude that monkeys retain a 'simple' dissonance-reductionmechanism that evolved in the primate line. Humans, by contrast, built on this simple mechanism and linked it to other processes, including those regulating our sense of self. And just as children take time to develop a full-blown disgust reaction (which is a cognitively complex reaction), and even longer to feel moral disgust, so too might children, like monkeys, initially make use of simple dissonance -reduction strategies, only later constructing the complex forms of dissonance reduction and ego preservation that we see in adults.

Notes
1. See Mistakes Were Made (But Not By Me) by Elliot Aronson and Carol Tavris for an excellent overview of the literature on cognitive dissonance and the strategies and situations that call for the deployment of powerful dissonance-reducing strategies.

2. Cognitive dissonance and its subsequent resolution are not the only, or perhaps even the preferred, explanation for this behaviour. A similar phenomenon has been observed in pigeons: in one study, food that took more effort to obtain from a feeder was preferred over food associated with less effort. This result was explained by ‘relative hedonic contrast effects’ – that is, the difference between the feeling experienced trying to get the food and that of actually devouring the food. When feeders exert more effort to get a given food morsel, they experience a greater shift in their relative hedonic (pleasurable) status, so the same food seems better after a worse experience. The same good explain some or much of the findings on effort-justification in humans.

3. Egan, L. C., Santos, L. R. & Bloom, P. The origins of cognitive dissonance – evidence from children and monkeys. Psychological Science 18(11), 978–983 (2007).

4. Jones, D. The depths of disgust. Nature 447, 768–771 (2007).

PSOM Back To Life!

After a long hiatus, PSOM is set to get going again. It’s been about a year since I last posted, and I should perhaps explain why I’ve not been blogging. Last December I left my job as an editor at the Nature Publishing Group to take up freelance writing full-time. Since then I’ve been busy writing as many features as I can, and I’ve been lucky enough to have the opportunity to write on a wide range on great topics, from human evolution and Neanderthal genetics, to delusions in romantic love, the psychology of disgust, the biases and pitfalls inherent in decision-making, genetically engineering the immune system, and the causes of breast cancer. I have a few more pieces in press with various magazines, and I’ll post details as the articles become available.

Freelancing is a tough, and at times isolating, business, but if you have work it is greatly rewarding – you get paid to learn about important and interesting topics, speak to some of the best minds around, and then tell other people all about it (with the help of what have, in my experience, been excellent editors). At the same time, it’s not a route to riches and there’s a constant feeling that your efforts should be directed at earning an income – hence the ease of neglecting blogging. It’s time to return to this pursuit though, as it’s both gratifying and a good way of keeping on top of the research I’m interested in (though I can only cover a tiny amount of what grabs my attention – there are only so many hours in a day!).

Anyway, I’m kicking things off again with a piece on the origins of cognitive dissonance – one of the best-studied and most fascinating psychological phenomena of the past 50 years. Hope you enjoy.

See you here again soon I hope,

Dan.

Delusions of faith as a science - Henry Gee on Richard Dawkins

Henry Gee, a senior editor at Nature who has handled many of the most important papers on palaeontology over the past decade, has weighed in on Richard Dawkins’s latest polemic, The God Delusion, in an online column for Nature. I take issue with practically everything Gee says, but exploring the issues raised is a useful way of finding your feet in debates about religion, and the relation of religious thought to scientific thought. Gee’s piece is short and my response long because I think a number of confusions get run together in a very short space in Gee’s column, and it takes a while to unpack what I see as the errors. So here goes, taking it from the top (I suggest you read Gee’s column before going any further).

The column kicks of with a story of Dawkins’s boast of disabusing a young child of a belief in Santa using scientific reasoning. Gee suggests that for Dawkins to argue against the existence of Santa Claus, and to doubt his ability to speed round the world delivering gifts to all the good children in the world, on the basis of the current state of scientific knowledge is nonsensical. Gee writes:

Santa can do everything he claims provided he is a macroscopic quantum object. In this way he can be in as many places as he likes, provided that he remains extremely cold, and nobody is watching. Not only does this trounce Dawkins' objections, it also works better as a scientific hypothesis, because it accounts for more of the evidence: we now know why Santa is traditionally associated with cold places, and why he does his work while everyone is asleep.

It is hard to know what to make of this ‘rebuttal’. There are at least two readings of Gee here. One is that, strictly speaking, scientific knowledge does not refute the existence of Santa, because we can invoke some scientific ideas to render the Santa proposal plausible, even though the notion of Santa who consciously chooses who gets gifts and delivers them personally is hard to square with a macroscopic quantum object.

This response brings to mind religious apologists, recruited to defend positions of dogma that from time to time come under attack. The task of the apologist is often not to put forward a positive set of arguments to support the position they wish to defend, but merely to show that the position could, in some conceivable way, be possible. Gee does much the same. Santa, as traditionally conceived and presented to children, is a normal three-dimensional object (of not a normal man) who flies round the world in a reindeer-powered super-sledge dispensing his gifts. What we know about the world rules out such a possibility: it would take too long, Santa couldn’t carry all the gifts, and the reindeer would vaporise through heat friction at the speeds at which they would have to travel.

So what does it show to say, “Well, if Santa is a macroscopic quantum object, it all makes sense”? Not much. There’s no reason to suppose that there is an entity answering to the name of Santa, and therefore no reason to posit either a normal or quantum object that we can identify as Santa. And indeed, it’s not clear that the idea of a quantum mechanical explanation of Santa even makes sense; it might not be a scientific alternative at all, and in any case it is an extremely desperate and unconvincing proposal (think apologists again!). Furthermore, the macroscopic quantum object idea hardly makes better scientific sense of the gift-receiving phenomenon that we have to explain, for we know that parents put the presents under the tree for their kids. There is no reason to believe that Santa exists — there’s not even a need to suggest he exists! — and the current state of knowledge suggests that the object we normally call Santa — fat jolly man with a big white beard and a bright red suit — could not do what he is charged with doing. If a child believes that Santa exists, and he doesn’t believe that parents supply presents each year, then the child could be challenged by appealing to scientific facts (not that I’d recommend this — I’m not defending Dawkins’s debunking per se, but merely the intellectual justification for it). No wonder the lampoon isn’t cited in The God Delusion.

The other reading might go like this: scientific evidence and reasoning are not relevant to the child’s belief in Santa, and so Dawkins’s approach is as ridiculous as Gee’s idea, which on this reading is Gee being deliberately silly. In one sense, this is right: kids don’t believe in Santa on the basis of reasoned reflection – they believe in him because it’s one of the more benign cultural myths we pass on to our kids. But this doesn’t mean that scientific evidence is irrelevant to either the child’s reflection on a belief in Santa as the child grows up, or our assessment of the reasonableness (in the epistemological sense) of the child’s belief. The evidence offered up by science argues against the existence of Santa, and nothing argues for it – as the parents who supply the presents will readily tell you. So if this reading is correct, it has no import at all, other than to say “Kid’s don’t reason their way to a belief in Santa”. We know this; the question is whether a belief in Santa would be supported by the evidence.

Gee goes on to say “My intention was to show that Dawkins' use of science to question the existence of Santa is nonsense. The reason is that science and belief are two quite different things, and a child's conviction that Santa exists lies firmly in the latter camp.” Of course belief and science are different things. I can believe all sorts of things that may be true or false – there is cheese in the fridge, wasps sting, pixies live at the bottom of my garden – but they are not science. However, that doesn’t mean there is no connection between belief and science. If I believe that there is cheese in the fridge, there’s an easy way to find out: open to door and take a look (of course, if it’s quantum cheese it’s location may be everywhere and nowhere until its wave function collapses and gives it a definite location; I’m talking about standard cheddar here). This is a scientific approach to addressing whether my belief in the cheese in the fridge is on the money – scientific in the sense that the hypothesis ‘there is cheese in the fridge’ is held up to an empirical test that will be answered by the facts of the world. So scientific investigation can provide ground for believing things and not believing things, and those beliefs that are supported by empirical investigations of the world might be called scientific beliefs.

Again, we have to ask what Gee means and intends to convey when he says “The reason is that science and belief are two quite different things, and a child's conviction that Santa exists lies firmly in the latter camp”. Here my reading of the statement. There is a body of hard-won knowledge, theories and hypotheses that we call science, and the notion of Santa doesn’t have a place within its walls. Nonetheless, some children still believe in this entity. Which makes me ask: so what? People believe in all sorts of things that are rightly not part of the corpus of scientific knowledge because they do not, in fact, exist (pixies, for one). The fact that the Santa idea is not scientifically supported or even defensible is a reason not to believe in Santa, even as a child (perhaps a precocious one). Children cannot be expected to realise this, particularly when they’re probably designed to be credulous with respect to the claims of their parents. To get back to the issue, the fact that a child can believe in Santa, and that this belief is not in the domain of science (and for good reasons!), doesn’t tell us a thing about the validity of the child’s belief (validity in the epistemological sense – you’re entitled to believe the moon is made of cheese if you wish, no matter how wrong you are). Of course, the point about Santa is an analogy, but what’s the point of all this? To demonstrate that some people believe some things that aren’t supported by science? Quick, stop the press!

All this leads Gee to “contest [Dawkins’s] central assumption, that the existence of God (or, if you like, Santa) is a hypothesis that can be tested scientifically.” This idea seems to be the most troubling one to people who adhere to religious beliefs. I think there’s a simple reason why: to accept that the claims made by the various religions are hypotheses, whether they are intended to be so or not, opens up the possibility of their disproval, and religious belief is almost designed to be irrefutable (not because the case for religious beliefs is watertight – it’s designed to be irrefutable in principle). Now, I’m not religious, but what am I supposed to make of the claim that people have souls, or that God underwrites moral law, or that we go to heaven or hell (or whatever your preferred destination is) after death? Are they not claims – factual claims – about the way the world is? They’re not metaphors, are they? They’re not allegories, or merely the expression of hopes and desires, are they? No, the claim that humans have souls seems to me to be a scientific claim on a par with the existence of the ether through which light travels or the phlogiston theory of combustion. Both had currency for a while, and then were displaced by improved scientific explanations. As far as the soul goes, there is nothing in the findings of modern science that suggest we need to invoke the notion, and no good reasons offered by anyone else that we do, in fact, have souls.

More broadly, the claim that there exists a God or gods who created the universe and set it in a motion is surely about the way things once were, and why they are the way they are now. If modern cosmology offers a narrative of the universe that conflicts with religious accounts, we can’t seal off the latter in a protective space and say, “Oh, actually, the claims religions provide are not supposed to be empirical claims about the universe”. If they aren’t, what on earth are they? Dawkins suggests that if the universe was created by a benevolent entity with certain characteristics and interests, then we should expect it to look one way; if it is instead the result of the operation of blind, indifferent physical laws, then we would expect it to look significantly different. Looking at the world as it actually is therefore relevant to adjudicating between the competing visions. (Of course, the existence of terrible suffering, childhood cancer, natural disasters and so on, which seem prima facie cases of facts of the world that point in the opposite direction to a divine and beneficent creator, can always be explained away by clever rhetoric in the style of Gee’s Santa theory – but when what you say about the way the world is can be made compatible with any future state of the world, you’ve offered a pretty empty explanation.)

I’ve dealt with the first four paragraphs of Gee’s piece – phew! Let’s move on. Gee’s next gambit is this:

The whole point about faith is that it should not be subject to scientific investigation or attempts of proof.

Now we’re getting to the heart of the matter. Strangely, however, Gee follows this with:

Douglas Adams (Dawkins' late friend and author of The Hitchhiker's Guide to the Galaxy) said, in the voice of God: "I refuse to prove that I exist, for proof denies faith, and without faith I am nothing." Given Dawkins' frequent quotation from Adams, it is odd that this most apposite of statements does not appear in The God Delusion.

Of course, with reasons and evidence in hand you don’t need faith (although it seems to me that the lack of reasons or evidence for God is the basis for insisting that belief in this entity should be based on faith!) The idea that beliefs based on faith are, according to the dictates of the faith system of which the beliefs are a part of, supposed to be immune from criticism, of either the rational or evidential kind, is not a point that is lost on Dawkins (he doesn’t need to quote Adams on this point, which in any case seems to contain an element of ridicule: what sort of a being demands that people believe in its existence, but refuses to provide any reason and instead insists that people take a blind leap of the mind and just say, “OK, I believe”; if I were that sort of God I’d have no respect for the people that did believe in me for no good reason). This protectionist notion of faith is one of the central issues that drives people like Dawkins and myself up the wall.

This is why. We all have beliefs about an almost limitless number of things. Some of these beliefs, such as the belief that the ground beneath our feet will remain solid, that the sun will rise tomorrow, and that an object falling towards us will continue until it hits us without intervention, operate beneath consciousness and are almost never questioned (at least the latter two seem to be part of our innate knowledge of physics). We also have beliefs that are more prominent in conscious reflection. These might include the belief that smoking causes cancer, that human activity is causing the planet to heat up, or that organisms evolved. In all these cases, people agree that your conclusions about the issue at hand should be based on reason and evidence – surely Gee wouldn’t publish a paper on evolutionary biology that offered mere assertions.
Then there is another set of beliefs that relate to the existence of supernatural entities such as ghosts, fairies, the power of crystal healing, and the various Gods of the world’s major (and minor) religions (I suspect that being lumped in this category will upset some people, but stick with me for a moment). These are claims that certain things exist and exert a causal influence on the world. In that sense, they are claims to be assessed like any other claim (such that protons exist, or that gravity curves space-time)*.

Now, of course, Gee and other religionists will object at this point and say, “No, you’re definitely not supposed to evaluate my claim about God like you do other things – it’s a matter of faith!”. At which point I ask: how on earth do decide in advance what areas of knowledge you should to fence off under the protective veil of faith? And isn’t it odd that religious traditions say, “Believe this, but don’t question it”. Does it not sound like a scam to get people to believe things that are palpably not true? Can you imagine if you went to a used-car salesman and he said, “This car goes like a dream – but I’m afraid you can’t take it out for a test run, or examine the motor. Take my claim on faith, and please don’t question my claim with demands for evidence”. You’d run a mile.

Gee perhaps thinks that having beliefs based on faith is some sort of virtue, but from my perspective it’s about the most serious intellectual vice one could have. It raises so many problems it makes your head spin. What should I have faith in? The God of Judaism, the God of Christianity, the God of Islam? Thor? Poseidon? The tooth fairy? How does faith even get going (obviously from a developmental perspective it’s something usually drummed into kids). As an adult, if three people come to me with different claims about supernatural entities, each telling me to have faith in their claims, and each touting the virtues of faith, how could I possibly decide what to believe, except by thinking “Oooh, that sounds nice”? Fair enough if that’s how you choose what to believe in, but you must recognise that you are therefore communicating to everyone else that there is absolutely no reason to listen to you when you claim that your belief is true. (Of course, most people don’t go around telling everyone else what they think is true, and what other people should therefore believe, but intellectual integrity means that if someone says “I believe X” they are saying “I believe X to be true”, and should be willing to defend that position – or else they should just say, “I believe X but I don’t claim it’s true – I just think it sounds good”, but no one does this).

We’re not done yet. The idea that religious belief, being based on faith, is immune to rational or evidentiary criticism has an important corollary that religious folk should take note of. Making this claim is, in effect, removing yourself from the realm of reasoned and reasonable discourse. If I meet someone who says “I believe X, and this belief is based on faith, and I will not subject this belief to logical, rational and empirical scrutiny”, then there is absolutely nothing left for me to say in reply to continue the conversation about the belief. The person has just shut the door to a rational conversation – worse still, they’ve cut themselves free from the tether of rationality and are floating free in their own realm of faith-based beliefs. Of course people are entitled to do this, but they must recognise that it is an absolute dead-end to further conversation. Which is why it is almost impossible to seriously engage in debate with anyone who has faith-based beliefs about those beliefs (unless of course you agree with them already).

This has been long and perhaps a bit pedantic, but the issues really matter, and so I can cope with being accused of over-nitpicking.

*Gee makes what I see as a superfluous distinction between ‘believing’ and ‘subscribing’ when he says “I ‘believe’ in God, but also ‘subscribe’ to evolution”. I’m in no way suggesting that philosophical debates about the nature of beliefs and knowledge, and what constitutes either state, are easy or settled, but if we uncontroversially take ‘belief’, as used in it’s everyday context, to mean “accept a proposition as being true” then why the distinction? In cases about the empirical world, we all, Gee included, have a number of beliefs: that fire is hot, the ground solid, and what is in our fridge (and sometimes we’re right, and sometimes we’re proved wrong, in both everyday life and science). So on this reading, Gee ‘believes’ in evolution along with a bunch of other stuff. He also believes in God. So why not just say that? Is saying ‘subscribe to evolution’ supposed to denote a more provisional acceptance of this claim than of the existence of a God, which Gee ‘believes’ in? I don’t know.

Dawkins the Dogmatist?

After reading Richard Dawkins’s new book, The God Delusion, Andrew Brown asks “who would have thought him capable of writing one this bad?” Are Dawkins’s ideas as daft as Brown suggests?

People are, quite obviously, driven to all sorts of acts for all sorts of reasons. People kill people for monetary gain, to eliminate competing sources of power, to exact revenge, and even to advance political causes that the killers think are just (this encompasses not just individuals but also governments that wage ‘just wars’ that will inevitably lead to the deaths of many people).

Brown’s review throws up the usual range of questions about the relationship of religion, and atheism, to behaviour, and the causal power of religion (or atheism) to induce people to acts of suicide and murder. Religion isn’t a necessary ingredient for these actions – but does that mean it’s irrelevant? And what about the role of atheism in motivating murderous behaviour? If religion is such a potent force in driving human behaviour, isn’t atheism just the same?

Brown writes:

Dawkins is inexhaustibly outraged by the fact that religious opinions lead people to terrible crimes. But what, if there is no God, is so peculiarly shocking about these opinions being specifically religious? The answer he supplies is simple: that when religious people do evil things, they are acting on the promptings of their faith but when atheists do so, it's nothing to do with their atheism. He devotes pages to a discussion of whether Hitler was a Catholic, concluding that "Stalin was an atheist and Hitler probably wasn't, but even if he was… the bottom line is very simple. Individual atheists may do evil things but they don't do evil things in the name of atheism."

Yet under Stalin almost the entire Orthodox priesthood was exterminated simply for being priests, as were the clergy of other religions and hundreds of thousands of Baptists.

Dawkins is suggesting that the motivation for certain ‘evil’ acts (not a word I like, but I think it’s clear that Dawkins means act that most of his readers would consider morally unacceptable) is sometimes religious belief, but that atheism does not have similar effects. Of course, this doesn’t mean that atheists don’t act immorally – presumably, according to Dawkins, when they do act in such a way it is not motivated by their atheistic commitments, nor is carried out in the name, or to advance the cause, of atheism. Brown responds with the line about Stalin killing the priests and the clergy. But what does this fact alone demonstrate? That an atheist committed mass murder – which tells us what? I’m no expert on Stalin’s reign, and so I don’t know what motivated his actions, but is Brown suggesting that his atheism per se was a decisive or contributing factor? It would seem so, when he writes “The claim that Stalin's atheism had nothing to do with his actions may be the most disingenuous in the book”. But what does Brown base the conclusion about the role of atheism in Stalin’s stunning inhumanity on apart from a correlation? If there is evidence that it atheism was a driving force, where is the evidence?

And there seems to be a bit of a double standard here. Brown seems irritated at Dawkins’s suggestion that religion can lead to terrible behaviour, but then tries to counter it with by showing that atheism can lead to bad behaviour. If it’s too simple to blame religion for bad behaviour, as Dawkins supposedly does, it should also be too simple to blame atheism, as Brown implies.

Brown also takes issue with the suggestion that religious fundamentalism is a causal factor in producing terrorist bombers:

[T]he definitive scientific study of suicide bombers, Dying to Win, has just been published by Robert Pape, a Chicago professor who has a database containing every known suicide attack since 1980. This shows, as clearly as evidence can, that religious zealotry is not on its own sufficient to produce suicide bombers; in fact, it's not even necessary: the practice was widely used by Marxist guerrillas in Sri Lanka.

Whenever people want to illustrate the lack of efficacy of religion in producing suicide bombers, they always cite the Tamil Tigers, who are inspired by a Marxism rather than an explicit religious agenda (indeed, may Tamils might be atheists). Again, we have to ask what this shows. Imagine that someone wrote a book on the dangers of smoking, and reviewers pointed out that not all smokers get cancer, and that non-smokers also get cancer. Would we say “See, smoking isn’t dangerous after all”. Of course not. The fact that smoking is neither necessary nor sufficient for getting cancer isn’t the point. Smoking can still be an important cause of cancer – even the most important cause of cancer (I’m not saying it is) – even if people get cancer for other reasons. And so when people tried to get smoking banned in public places, or taxes increased to put people off smoking, we wouldn’t be entitled to say “But look, there are some other know causes of cancer, so leave smoking alone!”. It would still be appropriate to single smoking out, critically discuss it, and definitely withdraw government support for it (if there were, say, smoking academies).

As I said at the outset, people are motivated to action by all sorts of things, such as political, social and economic inequalities, and the clash of cultures and values (although this is easy to overplay, and can be become something of a self-fulfilling prophecy). In the absence of any commitments to a supernatural being or, alternatively, fully naturalistic worldview, people will continue to rape, pillage, murder, wage war and carry out genocides. Similarly, if everyone stops smoking, some people will still get cancer. The question is whether religion is a causal factor in organised acts of terrorism and other condemnable actions, such as the killing of abortion doctors (and also whether atheism has similar effects) – which is like asking whether smoking causes cancer, regardless of whether other things do too.

This is not just about whether certain beliefs and actions are present together. I think we have to pay some attention to explicit reasons people give for their actions (though I appreciate this is far from the whole story – we’re often blind to the non-conscious psychological processes that mould our behaviour). When soon-to-be suicide bombers record their farewell messages, they usually cite a complex of factors that have driven them to this point. Often top of the agenda is a sense of social, political and cultural injustice. Their actions are designed to make a point on behalf of a particular group of people (today most usually a religiously defined community: Muslims). But there is also an undeniable religious component to their actions, which is evidenced by the very language in which their justifications are couched. Pro-lifers that kill doctors in abortion clinics are not shy in citing their faith, and the moral commitments it entails, is support of their deeds. Can we really dismiss as a motivating factor what the people whose behaviour we’re trying to understand actually tell us? Why would we want to?

As the Tamil Tigers show, you don’t need religion to be a suicide bomber. The psychology of human coalitions is complex and can clearly be affected by a number of inputs, from favourite football team to familial, ethnic, national or religious affiliation. Ingroup/outgroup hostilities can be bred by all kinds of symbolic badges, behaviours and beliefs. But this simply does not mean that religion should not be discussed as an important cause of strife and conflict. If religion was not such an important causal factor in suicide bombers, why were none of the 9/11 or 7/7 bombers non-religious? Why does religion feature prominently in the video messages the bombers recorded? Why, when a play is put on in Birmingham, do Sikhs in particular, and not the local community generally, stage threatening protests? Why, when the Pope quotes a 14th century writer, do Muslims burn effigies, make calls for capital punishment for those who insult their prophet, and turn up with placards saying “Jesus is a slave to Allah” and “Islam will conquer Rome”? In contrast, why don’t atheists turn up every time there’s a religious speech with banners saying “Behead believers!”? When have you heard of a group of people getting together and killing another group, and then saying “We did this because they believe in a God and we don’t”? If religion isn’t an important factor in motivating suicide bombers, why aren’t atheists, many of whom agree with the political complaints of many of the bomber, equally represented among the bombers?

The capacity for humans to commit the most atrocious acts on the fellow humans is strong enough without the moral support of a religious framework. Of course conflict in the world wouldn’t disappear if religions evaporated. No would cancer if people stopped smoking. But that doesn’t mean religion, or smoking, isn’t harmful. Why is it, then, that people are so eager to try to get religion off the hook, and not criticise its potentially dreadful effects? Even if Brown is right to say that a thorough-going atheism is unnatural to humans, that doesn’t equate to support for maintaining religions, or the funding of religious schools by the government.

Dawkins might oversimplify the link between religion and murder and immorality (I haven’t read the book, so I’ll suspend judgement), but in response his critics tend to go too far in trying exculpate religion for its negative consequences. The reality is more complex than perhaps either suppose.

Tenacious Neanderthals

Neanderthals, our closest relatives in the fossil record, might have survived for longer, and co-habited with modern humans more extensively, than previous studies have proposed, suggests a paper recently published online by Nature.

This year marks the sesquicentennial of the discovery of the fossilised remains of an individual that would become the prototypical, or type, specimen of a new species of human, Homo neanderthalensis. In 1856, lime quarry workers in the Neander Valley in western Germany recovered a number of fossils, including fragments of the cranium, of a human skeleton that was initially thought to be a diseased modern human. Later, as similar remains were found in other parts of Europe, the Neanderthals, as they were named in honour of their place of discovery, became accepted as a distinct, and extinct, type of human.

Neanderthal bones or their associated technology (including hand axes fashioned out flint) have since been found across Europe and into western Asia. Fossil remains bearing at least some of the distinctive features of Neanderthals are seen in bones 600,000 years old, although the full range of Neanderthal features don’t come together into the ‘classic’ Neanderthal form (such as the type specimen found in the Neander Valley) until about 100,000-200,000 years ago. The ancestors of Neanderthals (and of modern humans), H. heidelbergensis, lived in Africa, and about 600,000 years expanded into Europe and western Asia. This can be inferred from the trail of artefacts that they left across the newly inhabited continent. Stone tools, such as hand axes, first appear in archaeological sites around 1.7 million years ago in Africa, but then 500,000 years ago are seen all over the place in large areas of Europe. These technology-wielding people in Europe subsequently evolved into the Neanderthals (the stone tools used by the Neanderthals are called ‘Mousterian’ after the Le Moustier site in France).

The early humans that remained in Africa after the diaspora that led to the colonisation of Europe and the emergence of the Neanderthals later ventured out of Africa themselves, and into the Neanderthals’ range, sometime around 40,000-60,000 years ago. Anatomically modern humans had evolved in Africa roughly 160,000 years ago, but these later pioneers were also recognisably behaviourally modern, and the artefacts they made suggest a more complex culture and sophistication than either previous humans or Neanderthals. In fact, the presence of modern humans, or Cro-Magnons, in Europe is often inferred from the sorts of artefacts that are found in archaeological digs (and the same goes for the Neanderthals – it’s not just about bones). By about 45,000 years ago, modern humans lived in Europe and Asia.

Then something dramatic happened. Sometime within the past 35,000 years, after a good evolutionary innings, the Neanderthals stepped out of the evolutionary game, and modern humans went on, at least temporarily, to become masters of the sport of global dominance. Why the Neanderthals failed where the Cro-Magnons succeeded is a matter of intense debate. Potential explanations include a genocide by the Cro-Magnons against the Neanderthals, hostile climate, and the cultural superiority of the Cro-Magnons that gave them an edge in competition for resources and habitats. The notion that climate was the decisive blow to the Neanderthals has been re-asserted recently, but a problem with this idea is that Neanderthals seemed to have coped pretty well with climatic conditions that varied widely over a geologically rapid time frame (as quick as 1,000 years), and which could rapidly change glacial regions in to much warmer environments. Neanderthals managed with the challenges of climate for perhaps 30,000 years, so why did they stop coping after modern humans turned up?

One important issue to look at in exploring these explanations is whether Neanderthals and modern humans co-habited, and what the effects were of living together. The Neanderthals certainly disappeared after modern humans arrived on the scene, but how long was the overlap? A long period suggest that the modern humans didn’t suddenly wipe the Neanderthals through mass murderer, and could suggest that another factor did them in.

Like practically every question in human palaeoanthropology, this is a vexatious issue. Depending on which dates you rely on, and which sites you look at, the speed at which Neanderthals died out ranges from just 2,000 years in some places to 10,000 in others. These estimates are derived from the age of the earliest modern human remains (bone or artefact) and the latest Neanderthal in a similar location – both of which have potentially significant error bars. This makes the discovery of Neanderthal remains that are younger than previous finds very interesting, because it suggests that the Neanderthals persisted for longer and therefore died out more slowly – and so perhaps modern humans weren’t such a potent force after all (although you could perhaps draw the same conclusion about climate, and assume that any Neanderthals that survived later coped with the climate until modern humans came along).

Writing in Nature Clive Finlayson and colleagues report just such remains – of Mousterian artefacts, if not bones, in Gorham’s Cave in Gibraltar that they claim are at most 28,000 years old, and perhaps as young as 24,000 years. As the authors admit, this only allows a reasonable inference that Neanderthals inhabited the cave. But if this assumption is correct, and the dates accurate (which is contentious), then these findings push the date of the most recent Neanderthals a couple of thousand years nearer the present. The authors interpret this as evidence that Cro-Magnons were not such a potent evolutionary poison to the Neanderthals.

It is not clear, however, how significant these dates are, even if accurate. Perhaps modern humans weren’t in this outpost of southern Europe at the time, and the Neanderthals were surviving there just as they had done elsewhere in Europe, against the slings and arrows of outrageous climate change (perhaps Gibraltatr was a more hospitable locale, and that’s why they went there), until modern humans arrived and spoiled the party. Even if the general pattern of modern human contact with Neanderthals was rapid extinction of the latter, it seems reasonable to suppose that some areas would remained free of modern humans for longer than others, and that the dynamics of elimination of Neanderthals would have differed from region to region and across time. And so this find, remarkable as it is, seems to be compatible with the general idea that the evolutionary death knell for the Neanderthals was sounded by modern humans.

Future work will have to resolve the dating issues (John Hawks has a detailed discussion of some of the technical aspects of the find here), and assess the validity of the conclusions tentatively drawn from this study. But the contents of Gorham’s Cave are likely to provide another chapter in the increasingly long and complex book of human evolution.

For another good article on Neanderthals, this time their genome, see here.

Soap For The Soul

The notion of spiritual and moral purification through rituals of physical cleansing such as baptism might be based on more than mere metaphor, suggests new research published in a recent issue of Science.

Religious traditions are rich with elaborate ceremonial rituals that the faithful undertake with deep symbolic reverence. Many of these rituals involve cleaning the body as part of the process of washing away moral stains on the soul. Perhaps the most obvious example in mostly Christian societies is the practice of baptism (which also forms part of the religious traditions of Sikhism and Mandaeanism).

If the ritual of baptism was just a metaphor for the remission and washing away of the sins of the soul, it wouldn’t much matter how the cleansing was achieved. But the different forms of baptism carry different symbolic messages: some baptism ceremonies merely demand that water be sprinkled onto the baptee’s head from above (representing the gift of remission from God above), whereas others go for full submission to denote the death and burial of Christ and his subsequent rise from the dead as the Holy Spirit.

At a theological level, the point of a baptism is not to give the recipient a good wash, nor is intended merely as a metaphor for washing away sins: it represents some of the core values and cherished beliefs of the religious community in which the ceremony takes place. But might there be deeper reasons why such cleansing rituals are so widespread at all? Could it be that actually getting cleaner during these acts of worship actually makes the recipient feel literally morally cleaner, and that’s why the idea of cleansing rituals so popular? The new study, by Chen-Bo Zhong and Katie Liljenquist, provide some tantalising results that we really do behave as if soap and water can wash away a moral transgression (without even bringing God into the picture).

How might this work? Well, a lot hinges on the role and function of the universal human emotion disgust. Disgust is a strange emotion in that it can be aroused by a both physical objects (rotting carcases, bodily fluids and waste products and so on) and also people’s behaviour (rape, paedophilia and so on), unlike, say, anger: it doesn’t make sense it be angered by a rock, even if you stub your toe on it (though I admit I’ve shouted at a fair few number of inanimate objects). Psychologists have suggested that disgust originally evolved as protective gateway to the mouth: a mechanism to prevent the ingestion of dangerous foodstuffs (people around the world produce the same sort of facial expression as part of the disgust response). Later, the domain of disgust enlarged to include the social and moral domains, such that moral disgust became a defence against contamination and corruption of the soul. This connection is partially revealed by the habit of using many of the same terms for physical states that elicit disgust (dirtiness) for those that arouse condemnation (dirty behaviour) as well.

In fact, experiencing physical disgust produces bodily responses, such as facial expressions, similar to those caused by considering an immoral act. Even overlapping parts of the brain are activated by the two types of disgust reaction. So if similar brain areas and psychological states are activated by moral transgressions and physical dirtiness, then perhaps the intensity of the former could be reduced by acts that reduce the latter.

Zhong and Liljenquist call the phenomenon of trying to reduce the negative feelings associated with threats to moral purity the ‘Macbeth effect’. Striving to secure the throne for her husband, Lady Macbeth kills King Duncan, and tries to frame his servants for the murder. Racked with guilt, a somnambulant Lady Macbeth attempts to wash imaginary stains off of her hands, crying “Out, damned spot! Out, I say!” – wash away the blood, and the guilt will cleaned away too. The results of Zhong and Liljenquist’s study raise the potentially unsettlingly possibility that Lady Macbeth might have had more success in easing her conscience than we would ordinarily credit.

In the first experiment, Zhong and Liljenquist explored whether a threat to our moral self-image prompts a desire for physical cleansing. Participants were asked to dredge up an instance from their biographies in which they had either acted ethically or badly, and to describe the experiences associated with those recollections. They were then presented with a world puzzle of six word fragments presented like a partially completed game of Hang Man. Three of the fragments could be filled in to produce a word related to cleaning (W_ _ H, SH_ _ER, and S_ _P can be completed as wash, shower and soap, as well as wish, shaker and step). Participants who recalled an unethical deed from their past were more likely to complete these three fragments to form the cleansing-related words.

Previous studies have shown that subtle priming of a topic, below the threshold of awareness of consciousness, can make other words, concepts and behaviour related to the prime more likely to surface by increasing the accessibility of these concepts and behaviour. The increased accessibility of cleansing-related words, primed by a threat to moral self-image, suggests that the protective Macbeth effect really does exist.

The second experiments further probed the Macbeth effect: does this increased accessibility to concepts related to cleanliness actually relate to an increased desire to clean oneself? (It’s possible that the effect of word recall would be unrelated to any actual behaviour.) After being instructed to hand-copy a short written story, in the first person, that depicted either ethical or immoral behaviour, participants had to rate a series of supermarket goods. Some of the items, such as shower soap, toothpaste and cleaning products, were related to cleansing, whereas others, including Post-It notes, fruit juice and batteries, were not. In line with the proposed Macbeth effect, copying out the unethical theory had the effect of making cleansing products more appealing.

But again, expressed preferences are one thing, actual behaviour another. So Zhong and Liljenquist looked at whether, after being put through the set up in the first experiment, participants would prefer as a free gift a cleaning-type product (antiseptic wipe), over something with no cleaning connotations at all (a pencil, which had previously been shown to be an equally attractive choice in a control condition). Overall, those that had recalled some of their unethical behaviour preferred the antiseptic wipe, which again points to the operation of the Macbeth effect.

But this isn’t the end of the story. If the Macbeth effect exists, it’s likely to have some function, one that is fairly obvious: to protect our moral self-image, often a crucial guide to navigating our social and moral worlds. Other research has suggested that we strive to restore our moral identity after ethical transgressions, spurred on by the emotional consequences produced by reflecting on our actions. Sometimes this takes the form of making up for a bad deed with a compensatory good one. There is also evidence that merely contemplating a threat to some cherished value produces a desire to act so as to reassert that value.

If moral threats and damage to our moral self-image can be deflected and thwarted in ways that either reaffirm our values or restore on moral selves, perhaps they can be averted and fixed by more symbolic means that exploit the overlap between the domains of physical and moral disgust. So a key question is whether the bodily cleansing induced by threats to our conception of our moral selves actually has the proposed effect of reducing the magnitude of the threat, and its unpleasant consequences. Zhong and Liljenquist capped off their study by addressing this central issue.

In the final experiment, participants were again asked to recall a bad deed from their past. Half then washed their hands with an antiseptic wipe while the others didn’t, and all were asked to fill out a form surveying their current emotional state. Finally, they were asked whether they would donate their time, free of charge, to take part in another study for a desperate graduate student.

The negative feelings aroused by contemplating behaviour which the participants were not proud of would presumably have led to a desire (conscious or not) to make amends by doing something that expresses the moral commitments they would prefer to see in their self-image, or to otherwise erase the stain of moral impurity through an act of cleansing. In this set up, the cleansing option was forced on half the study subjects, which had the effect of reducing feelings of the negative moral emotions of disgust, regret, guilt, shame, embarrassment and anger (non-moral emotions were unaffected). Mere hand washing also reduced the likelihood of offering help to the student in dire straits – if you’ve cleaned your conscience, there’s no defect in the moral self-image to fix.

The implications of the Macbeth effect, and this demonstration of its power to influence moral behaviour, is potentially alarming, and leads to a counter-intuitive thought. If is often supposed that observance of religious practices and rituals forms a core component of an ethically grounded life. But these results plausibly point to an entirely different conclusion. If threats to the moral self-image of individual religious adherents can be countered through cleansing rituals rather than actually amending the moral offence, and if such rituals make compensatory moral behaviour after an ethical blunder less likely, then a religious life could, all else being equal, make the devout less moral! This is another empirical question, and it is likely that other factors will feed into the overt moral behaviour we observe.

In any case, physical cleansing, even if intended as a symbolic offering of commitment, seems a rather cheap and easy route to moral rectitude. But at least it might help make sense of how many ostensibly morally upstanding and devout followers of various religions can also be capable of living with themselves and a range of moral misdemeanours and sinful behaviours, sexual and financial*. And the celebrity pages are replete with cases of decadent, immoral stars who have renounced their wayward pasts, and been born into the glory of God’s kingdom through the miracle of baptism, all beneficiaries of the Macbeth effect. Perhaps for the faithful cleanliness really is next to Godliness.

*Of course, the religious aren’t alone in such self-serving attempts to restore moral integrity with a quick fix. We can all imagine the ruthless, atheistic businessman who rips of poor nations left, right and centre and then makes a seemingly large but to him insignificant donation to charity (tax deductible, of course) to assuage his guilt, which might not even be consciously acknowledged.