What causes behaviour?

//What causes behaviour?

The age-old debate as to what causes human behaviour – nature vs nurture – shows little sign of running out of steam, despite having been emphatically resolved as far as science is concerned.  Although all knowledge is contingent and no scientist worthy of the name would ever say there are no facts established completely beyond doubt, the mountains of evidence that have piled up in favour of genetic causes for behaviour as opposed to environmental ones is solemnly impressive.

No one argues that genes are wholly responsible for how we behave or that the environment has no effect on how we turn out. There’s definitely some sort of interaction between the two. You will, however, find plenty of folk who point out that genetic forces cause both social and behavioural factors. There are many examples of the coevolution of genes and culture – animal husbandry leading to an increased capacity to digest cows’ milk for example – and, even on an individual level, our genes shape our environments. The taller you are, the more likely you are to be picked for a basketball team; the more basketball you play, the better you’re likely to be at basketball.

Contrary to much popular wishing thinking, shared environmental effects like parenting have (almost) no effect on adult’s behaviour, characteristics, values or beliefs.* The reason we are like our parents and siblings is because we share their genes. Identical twins raised apart will be more similar – often strikingly so – than non-identical twins raised together and no less similar than identical twins raised together. Moreover, adopted siblings raised together will be no more similar than random strangers. Free will, it would appear, is nothing but a convenient and persuasive fiction.

So does this mean children’s behaviour in schools is, largely, biologically determined? No. School culture and policies can obviously mediate these genetic forces – we all moderate our behaviour in light of external expectations and social norms. But what is does mean is that an individual’s behaviour will be, for the most part, unaffected by this experience when outside the school environment. It also suggests that attempts to teach ‘character’ in the belief that such lessons will endure into adulthood are likely to be a waste of time.

No doubt many readers will not want to accept this, and it may provide some comfort to know you are not alone. A recent piece of research carried out by Joseph Carroll and colleagues has revealed a startling intellectual divided amongst academics. He and his team conducted a survey of over 600 academics in an attempt to establish the extent to which evolutionary thinking has embedded itself in other disciplines. Unsurprisingly perhaps, it turns out that psychologists, economists, philosophers and political scientists believe more strongly in the genetic influences on behaviour, beliefs and culture, while sociologists, non-evolutionary anthropologists, women’s and gender studies scholars and all humanities scholars other than philosophers believe in that environmental influences are more likely to explain human behaviour. What’s particularly interesting is that the latter group also tend to mistrust the scientific method itself.

Now, of course, science cannot ever meaningfully comment on what values we should hold or how we ought to act, but there’s no better method for providing answers to empirical questions on such matters as cause and effect. What causes human behaviour is just this sort of question. It doesn’t matter what you value or what you’d like to be true, testing and experiment all point in the same direction. Doubting the ability of science to answer empirical questions is dangerous.

As Carroll et al point out,

If all the disciplines discussing these questions agreed on the validity of scientific evidence, some eventual consensus would seem more likely. The low regard in which science is held by disciplines that emphasize environmental causes suggests that there are no common criteria of epistemic validity by means of which the two groups—those who emphasize genetic causes and those who emphasize environmental causes, and especially cultural causes—could work toward a reasoned consensus. (p. 27)

If you dismiss the scientific method then there are no grounds for your beliefs to be questioned – you can, quite literally, believe what ever you like and when anyone pops up with troubling evidence you can simply stuff your fingers in your ears and refuse to listen.

This seems awfully familiar when surveying the landscape of education debate. On the one hand there are those who are interested in discussing and debating evidence and how children think and learn, and what might be the most practically effective ways of running school systems, and on the other hand are those who believe in the primacy of feelings and intuition. If evidence is contradicting by belief, belief wins and no amount of reason, logic or rational debate will ever convince them otherwise.

Although there are many questions in education to which science cannot help us answer (What is the purpose of education?) just as with the identification of causes for human behaviour, there are plenty of empirical questions. Here are a few:

  • Do children learn more effectively when allowed to work collaboratively on ‘real world’ projects or when taught directly by a knowledgable teacher?
  • Is bullying most likely to be reduced in schools when children negotiate their own rules and engage in restorative approaches, or when there is clear adult authority and proportionate consequences?
  • Are children most likely to learn when they receive individual written feedback on their work or when teachers provide interactive whole class feedback?
  • Are outcomes more likely to be improved in a school when teachers’ lessons are regularly graded on a four-point scale or when teachers work together to support each others’ professional development?

We might not ever agree on the answers research throws up, but if we reject the validity of scientific evidence altogether, consensus will never be possible. As long as some dismiss the possibility that science can ever provide answers, we will always talk past each other.

*There are some obvious exceptions to this. Extreme neglect or abuse before the age of 5 will likely cause permanent developmental damage as will hitting someone in the head with a hammer at any age.



  1. chrismwparsons August 10, 2017 at 12:49 pm - Reply

    Is there some level of contradiction here?:

    “No one argues that genes are wholly responsible for how we behave or that the environment has no effect on how we turn out. There’s definitely some sort of interaction between the two.”

    “Contrary to much popular wishing thinking, shared environmental effects like parenting have no effect on adult’s behaviour, characteristics, values or beliefs.”

    Your second comment seems too strong to me.

    I know in the past you have emphasised the role of peer environmental influences over parental or indeed schooling ones in terms of behaviour (from The Nurture Assumption), but surely beliefs must have a massive correlation with what it is we are taught, and behaviours must have a significant correlation with the beliefs that we hold.

    Otherwise, you’re saying (for example) that the teaching of creationism in churches and schools has nothing to do with beliefs in it in adulthood, or that jihadi teachings and beliefs have nothing to do with the behaviour of people who bomb other people in its name – possibly knowingly giving their own lives in the process.

    In effect what you’re saying is that we need to erase from our language the notion of people being ‘brain-washed’ to believe certain things, and act in a certain way, and any twin studies of two arab children separated at birth – one being brought-up by ISIS and subsequently committing terrorist attacks on civilians – should find that a separated twin brought up by a secular western family will also go on to do similar things – perhaps for some western political cause. You would think then that Richard Dawkins, as an eminent geneticist, would portray opinions such as these very differently: http://freethoughtnation.com/richard-dawkins-islam-is-one-of-the-great-evils-of-the-world/ Shouldn’t he be saying that it’s not Islam, or any other belief system that perpetuates such actions, it’s genetics?

    • David Didau August 10, 2017 at 1:32 pm - Reply

      As to Dawkins and Islam, yes he should. Religious belief is highly heritable. While it’s true that cultural information (such as religion) will be passed on by parents, what we choose to believe and how we choose to act as adults is not determined by this process of enculturation. We may not ever question some of what our parents passed on as true, but whether we become a jihadi or not will be down to heritability plus peer influences which are, in large part, mediated by our genes.

      I would guess that susceptibility to ‘brainwashing’ is almost certainly highly heritably. Whilst you may never know without the environmental factor of someone trying to brainwash you, I would predict that some people cannot be brainwashed.

      The ‘assertion’ that parenting has no effect on adult behaviour is not mine. It is a widely accepted scientific consensus. If you want to disbelieve it, that’s fine, but there is a lot of evidence for you to explain away first. As a starting point I recommend reading The Blank Slate by Stephen Pinker.

      • chrismwparsons August 10, 2017 at 1:59 pm - Reply

        Thanks very much for the detail of you response David – I’ll certainly dive into the HBD resources. Would the following be about right then:
        1) Religious creeds are transmitted culturally, but the disposition towards religiosity is genetic.
        2) If the dominant cultural creed doesn’t endorse violence paths of action, would-be bombers will simply find alternative anti-social outlets for their violent tendencies…?

        • David Didau August 10, 2017 at 3:24 pm - Reply

          Yes, I think both of those points are broadly correct

  2. Elizabeth Nonweiler August 10, 2017 at 2:47 pm - Reply

    I am with chrismwparsons. I understand that genes have more effect on behaviour than environment, but I find some of your claims confusing. You wrote that “shared environmental effects like parenting have no effect on adult’s behaviour, characteristics, values or beliefs,” but obviously the religion or non-religion you are brought up with influences your behaviour and beliefs as an adult. The adopted child who never met her Hindu birth-parents or was aware of their religion and was brought up as a Christian, knowing no Hindus, is unlikely to worship as a Hindu. I know I have misunderstood what you wrote.

    A separate point: You wrote, “Identical twins raised apart will be … no less similar than identical twins raised together.” I think it may be that identical twins raised apart will be MORE similar than those raised together. I say that for two reasons. First, I think I read some research that found evidence for that. Second, and this is anecdotal, I know some identical twins. When they lived together they deliberately chose to do some things differently. For example, at school they chose to study different A-levels and learn different musical instruments and they always dressed differently. As adults they moved to opposite sides of the world. When they came together on holiday, having not met for a long time, to everyone’s amazement they turned up for a picnic in very similar clothes, including straw hats.

    • Elizabeth Nonweiler August 10, 2017 at 2:50 pm - Reply

      I posted the last message before I saw David’s response, which answers my first paragraph.

    • David Didau August 10, 2017 at 3:27 pm - Reply

      1. I answered this point specifically in my reply to Chris.
      2. That’s just anecdote. If you can find a study suggesting twins raised apart are more similar I’d be very interested to read it.

  3. julietgreen August 10, 2017 at 4:04 pm - Reply

    Yes. It’s a non-debate that rattles on, much like the ‘climate change’ controversy. The only difficulty I have is that I’d like (and I know you’ve written about this) a better proxy for ‘learn more effectively’ than the ones we currently have. I’d prefer people to understand that there is no evidence that ‘collaborative work on real world projects’ leads to better learning, than to say that direct instruction from an expert does. The latter may well be true, but are the measures we use sufficient evidence of what we mean?

  4. Elizabeth Nonweiler August 10, 2017 at 6:00 pm - Reply

    In reply to David:

    Yes, you answered my first point satisfactorily. Thank you.

    I know my second point was anecdote and said so. I base my convictions on a mix of anecdote, my own experience, logic and the research I read that appears to be unbiased and scientific. If I find the parts of this mix are contradictory, I have to reconsider. It may be that the anecdotal or my own experience or my logic is misleading. On the other hand, it may be that the research is flawed.

    If I find the relevant research about twins I shall let you know.

    • David Didau August 10, 2017 at 6:20 pm - Reply

      It *may* be that the consensus of the life sciences is wrong, but it will take more than personal experience and conviction to contradict the huge weight of evidence. Thanks 🙂

  5. Elizabeth Nonweiler August 10, 2017 at 6:36 pm - Reply

    I agree. Where there is overwhelming scientific research evidence, that outweighs all the rest.

    • David Didau August 10, 2017 at 6:43 pm - Reply

      Which is very much the case in this instance.

      • chrismwparsons August 10, 2017 at 7:19 pm - Reply

        Interestingly, the logic of your position suggests that if Elizabeth (or anybody else) was behaviourally predisposed to weight her personal intuition/experience more heavily than the words of researchers, then nothing you say here to her would make any difference in convincing her of the truth of your argument… 😀

  6. geoffjames42 August 10, 2017 at 10:10 pm - Reply

    Just ideological. Not accurate. I’m a biologist. You’re obviously not. Read about epigenetics and then have another go.

    • David Didau August 11, 2017 at 7:33 am - Reply

      I’ve read a lot about epigenetics. What specifically do you consider to be inaccurate?

  7. @davowillz August 10, 2017 at 10:24 pm - Reply

    I can’t see the sense on this one David. Are you just trying to be provocative? I can’t really believe that you think free will is a fiction. Especially as earlier you suggested earlier that our behaviour is a result of genetics and environment. Also adopted children are often told they seem to take after their adopted father or mother by those who don’t know they are adopted. I don’t think science is as certain as you suggest about nature nurture argument.

    • David Didau August 11, 2017 at 7:33 am - Reply

      I can’t really believe anyone with even the slightest modicum of scientific literacy *does* believe in free will. Science is never certain (as the post makes clear) but your beliefs notwithstanding, this is the consensus of the life sciences.

      Obviously, your response is – probably – not something you can control 🙂

  8. […] I think that David Didau’s last post contained a number of grave […]

  9. Tim Conroy-Stocker August 11, 2017 at 2:48 am - Reply

    Some interesting ideas here but I think you are quite reductionist in your explanations of behaviour. I think the best a psychologist can ever say is that we have some ideas about what may influence behaviours of children in school. As a teacher and an educational psychologist I believe my best tool is an open mind with an awareness of the huge range of theory and evidence about what motivates and impacts on children’s learning and behaviour.

    In actuality what seems to matter the most in terms of how successfuly things work out for teachers and students are their own perceptions/ beliefs or constructions about what is going on for them and their teaching/ learning.

    So interesting research, but a bit simplistic in ignoring Humanistic/ Posititive psychology and Personal construct approaches, among others. Not sure if I would last long as an Ed psych if I advised teachers of children with special educational needs ‘There’s not much you can do, the behaviour’s all genetically caused anyway…….’

    • David Didau August 11, 2017 at 7:37 am - Reply

      Ignoring humanist/positive psychology is the most respectable intellectual position I can imagine taking. I’m sure you wouldn’t last long taking the view you describe – it would be obviously untrue – as the post makes clear, there’s a lot schools can do to mediate children’s behaviour. In the same way, if you were short sighted you could be prescribed glasses.

      • Tim Conroy-Stocker August 11, 2017 at 9:00 am - Reply

        12 years and counting so far, with a further 12 years as a teacher before that… I would give you about 6 months…

        • David Didau August 11, 2017 at 9:06 am - Reply

          Always time to learn Tim. Ignorance is not inevitable 🙂

          • Tim Conroy-Stocker August 14, 2017 at 1:45 am

            Agreed…but it sometimes seems that way 😉

          • David Didau August 14, 2017 at 10:31 am

            I’m keeping my fingers crossed for you

      • teachwell August 11, 2017 at 9:06 am - Reply

        But if schools can mediate behaviour then why can’t parents? My confusion here comes from why certain environments impact on behaviour and mediate while others don’t.

        • David Didau August 11, 2017 at 10:47 am - Reply

          Parents can. It just doesn’t last any longer than schools’ effects. Parents have a huge degree of influence on children *while they are children*. As they become increasingly independent, these effects wash out.

          • Harry Anderson August 16, 2017 at 8:59 pm

            Are parents then replaced by partners, peers, colleagues, general ‘groupthink’?

          • David Didau August 17, 2017 at 7:41 am

            To some extent, yes, although ‘replaced’ is probably the wrong word. Parents only seem to exert influence over children whilst in the family home – when they are with friends any inconvenient values/beleifs are dropped in favour of the peer group consensus. As adults this just accelerates.

  10. […] What causes behaviour? (The Learning Spy) Although there are many questions in education to which science cannot help us answer (What is the purpose of education?) just as with the identification of causes for human behaviour, there are plenty of empirical questions. […]

  11. […] an aside in a recent blog, I made the statement that, “shared environmental effects like parenting have no effect on […]

  12. Anna August 12, 2017 at 12:50 am - Reply

    If society, our parents and our peers have no significant impact on our beliefs as adults, does that mean we’re predisposed (as a species) to think that men and women or certain races are not equal etc? If so, we should stop striving for equality, shouldn’t we, as it’s a waste of time.

    • David Didau August 12, 2017 at 7:52 am - Reply

      Society & peers *do* have significant impact on our behaviour. It’s just parenting that doesn’t.

  13. Jen J August 14, 2017 at 1:51 pm - Reply

    here’s what a thoughtful, careful philosopher who’s spent his life looking into this question by closely reading and talking to scientists who work on it has to say. roughly, even in very simple organisms whose behavior and development can be precisely tracked, almost nothing about behavior is heritable. for human beings the question is essentially a nonstarter. http://newbooksnetwork.com/kenneth-schaffner-behaving-whats-genetic-whats-not-and-why-should-we-care-oxford-up-2016/

  14. […] efforts to move heaven and earth to deny the reality of inconvenient empirical data. As I explained here, all this results in identity politics, post-modernism and the denial of scientific […]

  15. […] bafflingly wrongheaded to ignore in favour of believing what we prefer to be true. As I reported here, there seems to be a correlation between the tendency to down play the role of heritability in […]

  16. […] when assessing performance in our classroom. Video here. Article here. Blog from David Didau here. Behaviourism vs cognitivism article […]

  17. […] when assessing performance in our classroom. Video here. Article here. Blog from David Didau here. Behaviourism vs cognitivism article […]

Constructive feedback is always appreciated

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: