May 31 2012

Richard Leakey, Evolution and Motivated Reasoning

Richard Leakey, son of Mary and Louis Leakey, is a deservedly famous paleoanthropologist who has contributed significantly to our understanding of human evolution. In a recent interview he expressed his confidence that skepticism over evolutionary theory will fade away over the next 15-30 years. He is quoted as saying:

“If you get to the stage where you can persuade people on the evidence, that it’s solid, that we are all African, that color is superficial, that stages of development of culture are all interactive,” Leakey says, “then I think we have a chance of a world that will respond better to global challenges.”

While I hope this is true, I am not as optimistic. I think the primary problem with his argument is the premise that you can get to the stage, “where you can persuade people on the evidence.”  In my opinion the evidence indicates that for many people, you cannot persuade them on the evidence. Unfortunately, human psychology simply does not work that way.

I agree with his premise that the evidence for evolution as a fact is overwhelming. In fact, I think we are already there. We do not need to wait 15-30 years for the evidence to be solid and convincing. There is a confluence of evidence from genetics, paleontology, anatomy, and developmental biology that has only one scientific explanation – common ancestry and organic evolution. We’re still working out the details, but the big picture is crystal clear.

Leakey says:

“You can lay out all the fossils that have been collected and establish lineages that even a fool could work up. So the question is why, how does this happen? It’s not covered by Genesis. There’s no explanation for this change going back 500 million years in any book I’ve read from the lips of any God.”

He seems to be agreeing with my position – the fossils are already so compelling that “even a fool” can see the obvious connection. So why, then, are there so many people who doubt evolution?

The key variable seems to be how tightly held a belief is. For those ideas and claims about which we do not have any serious emotional investment, we can behave rationally and follow the evidence wherever it leads. For those ideas in which we have an emotional stake, however, humans seem to have an unlimited capacity for what is called “motivated reasoning.” We are really good at finding reasons to dismiss ideas or evidence we don’t like, and for accepting notions we prefer, no matter how absurd and contradicted by evidence they may be.

Psychologist Kunda wrote in 1990 about motivated reasoning:

It is proposed that motivation may affect reasoning through reliance on a biased set of cognitive processes–that is, strategies for accessing, constructing, and evaluating beliefs. The motivation to be accurate enhances use of those beliefs and strategies that are considered most appropriate, whereas the motivation to arrive at particular conclusions enhances use of those that are considered most likely to yield the desired conclusion. There is considerable evidence that people are more likely to arrive at conclusions that they want to arrive at, but their ability to do so is constrained by their ability to construct seemingly reasonable justifications for these conclusions. These ideas can account for a wide variety of research concerned with motivated reasoning.

Since then research has reinforced the notion of motivated reasoning. A recent study, for example, concludes:

Three cognitive mechanisms are identified: a prior belief effect, confirmation bias, and disconfirmation bias.

We tend to hold onto a belief we already have, and we tend to seek out and accept confirming evidence while finding reasons to dismiss contrary evidence. Further, in a study by Nyhan and Reifler subjects who were given correct information that contradicted a tightly held political belief actually strengthened their original belief, in a so called “backfire effect.” Being subjected to information that contradicts their desired belief seemed to activate their motivated reasoning and cause them to dig in their heels even harder.

Anyone who has dealt with creationists should be familiar with the degree of motivated reasoning involved. Examples are legion. I was just sent a news item (an almost daily occurrence) reporting about a man from Georgia called Bob Staples who believes that evolution should not be taught in public schools. In a letter to the state board science committee he wrote:

“Presenting evolution as fact should be a concern to all Georgians. That evolution is not a fact of science and shouldn’t be taught.”  ”To teach it as a fact is lying to people.”

He also claims:

“The crime rate, child abuse, divorce. All of these things rose from a period following the implementation of teaching Darwinian Theory.”

That last bit is classic confirmation bias. Crime rate has risen and fallen over the last century. In any case, these are complex social phenomena and it is ludicrous to assign cause and effect to a single factor, especially one that would have such an indirect effect such as the teaching of evolution (besides, I thought it was rock and roll that was the cause of all modern social ills). We could just as easily point to many of the positive social trends, like decreased discrimination, and credit the teaching of evolution.

If simply providing more and more evidence for the fact of evolution is not going to change the minds of people like Staples, then what will? I wish I knew. There doesn’t seem to be any magic formula. My guess, and a major motivation for my skeptical activism, is that giving people critical thinking skills can only help. We need to shift our motivation away from any one particular conclusion and toward being logically valid and correct on the facts. If people are more motivated to be rational than to be correct on any one point, they should be more likely to engage in effective (rather than motivated) reasoning.

We need to also give them the cognitive skills to reason effectively. This involved educating the public about logic, scientific methodology, and so-called metacognition – thinking about thinking.

There is no point in arguing with a creationist who is stuck is a creationist world view, who is engaged in motivated reasoning, and who does not have the intellectual tools to analyze their own logical fallacies and cognitive biases. If you teach them critical thinking, however, they might at some point turn their critical thinking skills to their own evolution denial. I have seen it happen.

 

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18 responses so far

18 Responses to “Richard Leakey, Evolution and Motivated Reasoning”

  1. bluedevilRAon 31 May 2012 at 9:26 am

    I agree that it is nearly impossible to change someone’s mind that has a deeply rooted belief such as creationists and antivaxxers. However, I wonder if Leakey meant that if the evidence continues to mount then there will be some fence sitters, shruggies, etc that join the side of science as the anti-science folk fade into obscurity. In the last hundred years or so we have seen animal rights, environmental rights, women’s rights and civil rights all gain significant traction despite very entrenched positions. How were beliefs and ideas changed in those situations?

  2. Steven Novellaon 31 May 2012 at 9:38 am

    I agree that the creationist position can be marginalized, even if we can never eradicate it. That may be a generous interpretation of what he said.

  3. daedalus2uon 31 May 2012 at 10:15 am

    When I saw Leakey’s statement I though he was being naive too. Maybe he was thinking of this quote from Planck.

    “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it.” – M. Planck

    The new beliefs that bluedevil mentions didn’t arise because of new data.

    Belief in Genesis didn’t arise because of any data. Those beliefs occurred because someone made them up and told them as if they were true and people believed them because it ingratiated them with the people who were in power who were telling the stories.

    If we can produce a disconnect between believing stories that someone tells and acquisition of power and authority, then maybe there will be a way to move society to more science and reasoning based.

  4. bluedevilRAon 31 May 2012 at 10:37 am

    I also think 15-30 years is a bit generous on his part. I can only hope it takes that little time, but I sincerely doubt it. It is going to take many great science educators to serve as catalysts by bringing the evidence for evolution to the public. I know many people that lack strong science backgrounds and are completely unaware of hominin fossils other than Lucy. This is a serious barrier to the acceptance of evolution. That being said, there are clearly many people like Wendy Wright who are lost causes. The “backfire effect” study is very interesting and I think it applies to people like her. So I guess the real question is how many people that have doubts about evolution are hardline creationists and how many are just following what someone else has told them without really thinking.

  5. Bronze Dogon 31 May 2012 at 3:22 pm

    On making the next generation grow up with the ideas, I suppose one way to do it would be to spread the use of genetic algorithms or generally make them more visible. If the theory of evolution, working through genetic algorithms, produces readily visible results for “mundane” purposes and kids are made aware of the process, they’d probably be more inclined to believe it.

  6. SARAon 31 May 2012 at 4:45 pm

    I agree with Steve! The key is to teach critical thinking skills. I think we should be making it a serious, pervasive and ongoing part of education from kindergarten through graduation. We are so upset that people don’t know basic facts when they get interviewed on the street. I think we should be more upset that people are at a complete loss as to how to think logically.

    There is some value to debunking bad thinking as skeptics do. But the hard fight is going to be in raising a generation of kids that think instead of believe. We need to be actively campaigning to change school curriculums. To promote more critical thinking reality shows, to make thinking an issue in the first place.

    I try very hard not have a belief. I define belief as an idea that I have become emotionally entrenched in. I try to keep myself to ideas that I want to learn more about. Its hard to do. For example the skeptical community has several ideas that could easily become entrenched, making me lose that critical edge. But just because an idea is good, doesn’t mean it shouldn’t be open to change upon evidence coming in.

    If we change the cultural norm to thinking critically a whole lot of issues will cease to be problematic. For example politicians would have to present a real platform with plans that have evidence for working. Imagine who would run then.

  7. Michaelon 31 May 2012 at 5:44 pm

    Great post!

    I’ve recently been having arguments with a few friends of mine who I was surprised to find out they didn’t believe in evolution, so this post was relevant to me as well.

    I took my first philosophy critical thinking class as a “general education” paper in my first year of uni (Now I’m on my second) and I loved it. It made me wonder something; why isn’t critical thinking introduced as a major subject in early education? If throughout high school we had been taught Maths, Science, English WITH Critical thinking as compulsory subjects, then maybe we would be surrounded by a smarter world which doesn’t feel that an ‘argument’ is an aggressive conflict. I’m from New Zealand – so maybe its different around the world and in the States, but I would say that critical thinking should really be a subject that’s put on a pedestal.

    Thanks again Steven Novella, I really enjoy this part of the web.

  8. Lee Bowmanon 01 Jun 2012 at 6:50 am

    There is no point in arguing with a creationist who is stuck is a creationist world view, who is engaged in motivated reasoning, and who does not have the intellectual tools to analyze their own logical fallacies and cognitive biases.

    Agreed. Those of that ilk, in particular YECs who insist upon encroaching established science with false determinations, based on their preconceptions. But those who are open to teleological possibilities, but based on supportive data only, are well within the scope of objective scientific perusal. And to assume a BFF conflation of the two [Barbara Forrest Façade] are simply employing politics to further their own a priori agenda.

    If you teach them critical thinking, however, they might at some point turn their critical thinking skills to their own evolution denial. I have seen it happen.

    Or, they may simply modify their view of life in a way that no longer holds to dated creationist precepts. But regarding those who may go with a total rejection of a purposeful realm, and a [in-part] designed biosphere in toto, I would add a note of caution. If truly objective [critical] thinking is on the table, neither hard theism nor hard atheism need be. Neither embody truly ‘rational thought.’

    I’ve been called a Creationist, but there is no one I’ve come across who is more of a skeptic than me, having flunked American History twice due to disagreements with the biased and Chauvinistic text, and both Profs. Ed Downey and Dick Joranko [Royal Oak Dondero HS, 1957]. I sided with the Brits, the French and the Indians on more than one occasion, but based on the facts, rather than a self-serving agenda, which was viewed as un-patriotic. I currently hold to a liberal ID view, but based only on observable data, and on some experiments I did in the 60′s. And my conclusions are subject to change with renewed data.

    That said, and as I believe that commenter Sara stated, critical thinking is the key to objective science. The cultural [and purported anti-science] wars in progress benefit no one, and in particular degrade rather than defend science. I side with a skeptical position in regard to aspects of science not readily empirically testable, and there are many such areas of various ancillary views [consciousness as an agency/ entity, not just an effect].

    And by ‘testable’, I’m referring to objective and unbiased analyses of test results, which are sometimes skewed by a priori [firmly in-place] premises. It’s fine to make and hold to predictions, but not to embed them in the foundational theories they only seek to reinforce.

    I agree with [Leakey's] premise that the evidence for evolution as a fact is overwhelming.

    Me Too!

    In fact, I think we are already there. We do not need to wait 15-30 years for the evidence to be solid and convincing. There is a confluence of evidence from genetics, paleontology, anatomy, and developmental biology that has only one scientific explanation – common ancestry and organic evolution. We’re still working out the details, but the big picture is crystal clear.

    The term ‘overwhelming’ does indeed refer to the data; but not in regard to unalterable conclusions. So yes, let us work to encourage unbiased and objective perusal of science, but with a de-emphasis on established premises, however widely accepted.

  9. Kawarthajonon 01 Jun 2012 at 2:30 pm

    I was waiting for Steve to write about this story – it seemed right up his alley.

    I think the opposite of what Dr. Leakey predicts will occur – science education is dropping off in many parts of the world, especially in the US. There has been a constant battle to sow “doubt” about evolution as a theory, much like there has been for global warming. Sowing this doubt is the most effective way of undermining the general public’s support for scientists and science in general. When the general public does not support science, populist politicians get elected on anti-science, pro-religion platforms and they begin to develop public policy that is bad for science education. With fewer people getting good science education, less people support scientists and science in general and more populist politicians get elected…. and there goes the cycle. So, it is not the scientific theory of evolution that is having problems, it is the populist view of evolution that is problematic.

  10. PhysiPhileon 01 Jun 2012 at 3:22 pm

    Can someone tell me what critical thinking really means?

    I hear those words thrown around a lot around these parts – it seems that most of y’all think it has something to do with the elucidation of facts via scientific methodology. However, if I were with friends who do unconventional warfare (special forces) they would define critical thinking as the strategy employed to kill the most people with the fewest bullets in the shortest time.

    Seems like everyone wants critical thinking…including skeptical enemies

  11. NewRonon 01 Jun 2012 at 8:55 pm

    At last after thousands of years of civilization we have arrived at that point in mankind’s history where the truth has become accessible. Our scientific and materialist methodology is sound, there can be no question that at last we can forge ahead to banish superstition, new age drivel and, most importantly, their progenitor – religion. And we are acquiring the means to accomplish our goal of establishing critical thinking and disestablishing the illusion based belief systems that have caused so much suffering in our past.

    We see our way clearly ahead of us. Neuroscience is slowly but surely giving us the means to alter people’s brain states – chemical and mechanical interventions will become the norm to establish the norm, our norm that we know with all of the certainty of critical thinking to be the true ‘way humans should be’ norm. It cannot be beyond our capabilities to eventually develop a pill that will chemically adjust the brain to accord with this norm that will of course be based on proper DSM standards.

    In tandem with this great enterprise we will build machines that will operate on a purely rational basis. We may even be able to make these machines sentient. At the very least they will provide us with a template upon which to model our new society.

    Evolution has brought us to this glorious point in our history – we cannot afford to let the opportunity slip by us.

  12. SARAon 01 Jun 2012 at 9:42 pm

    PhysiPhile.
    I think Wikipedia has a decent review of it. I summarize it for friends as using evidence and careful logic to evaluate ideas. Humans are hard wired to make assumptions and we often take that ability too far and come to false conclusions. It important to recognize that and stick to evidence whenever possible.

  13. PhysiPhileon 02 Jun 2012 at 2:41 am

    At last after thousands of years of civilization we have arrived at that point in mankind’s history where the truth has become accessible.

    Pssshh..arrived? No way! What do you mean by truth? You act like there is “a truth” to the universe. What makes you so sure? Yeah, there’s definitely a consistency to the universe. We invent ideas then test them against observation – if they fit we see if they can predict something more then we have a better understanding but you make it seem as though we running full speed towards some truth. Truth is, there could be just a shit load of perspectives and no absolute truth. Much of science thus far has delt with a linear type of reductionism but [opinion] most of the good things in life [/opinion] is not amendable to such analysis. We occupy such a small slice of time that I am skeptical of anyone who claims that we are at some critical point of scientific inquiry or realization.

    “We see our way clearly ahead of us.”

    Bullshit

    “chemical and mechanical interventions will become the norm to establish the norm, our norm that we know with all of the certainty of critical thinking to be the true ‘way humans should be’ norm.”

    And what is this “norm” shit? You almost sound like a hardcore religious person when you talk is some terms like that. Evolution doesn’t give a shit about norms…it wants variability to select phenotypes that increase bio mass.

    “In tandem with this great enterprise we will build machines that will operate on a purely rational basis.”

    Uhhh hows is that different than any computer? What’s hard is the nonrational human part.

  14. BillyJoe7on 02 Jun 2012 at 4:12 am

    Steven Novella: “If simply providing more and more evidence for the fact of evolution is not going to change the minds of people like Staples, then what will?”

    The elephant in the room: RELIGION.

    Forget facts.
    Forget critical thinking.
    Religion trumps both.

    It will take the marginalisation of religion for the populace to accept evolution.

    And it is already happening.
    There is a graph somewhere showing religious belief and acceptance of evolution is countries around the world. The least religious are also the most accepting of evolution. The USA comes second only to Turkey in relgious belief and rejection of evolution.

  15. BillyJoe7on 02 Jun 2012 at 4:26 am

    daedalus: ““A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it.” – M. Planck”

    The battleground is therefore the children of religious parents.
    The stradegy is to loosen the grip of the parent’s religion on their children.
    The rest will be child’s play.

    Well, it worked for me anyway.

  16. NewRonon 02 Jun 2012 at 5:10 am

    We should emblazon above the gate into our brave new world, “Critical Thinking Will Set You Free”.

  17. NewRonon 02 Jun 2012 at 5:15 am

    All memory of Max Planck will be obliterated in our brave new world. His thoughts might contaminate our youth. How dare he assert:

    ‘All matter originates and exists only by virtue of a force… We must assume behind this force the existence of a conscious and intelligent Mind. This Mind is the matrix of all matter.’

  18. daedalus2uon 02 Jun 2012 at 10:55 am

    SARA, your definition is close, but rather than being based on “evidence” it should be based on data, or facts. Testimony about something can be considered “evidence”, but that testimony may be false.

    It is a subtle point, but using “evidence” as the standard allows one to differentially weigh that evidence based on subjective criteria. That is all that the YECs are doing, they are weighing the “evidence” and awarding enormous weight to handed down traditional stories of illiterate bronze age nomadic shepherds.

    It is a fact that certain traditional stories of illiterate bronze age nomadic shepherds assert things about the creation of the Earth and about reality. Many of those stories are not consistent with other data and facts that are easy to observe and measure today. The stories and the present data are both “evidence”, but the data that can be measured and remeasured today has higher reliability than stories of uncertain origins.

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