Science Talk

Why People Believe What They Do

University of California, Berkeley, psychologist Tania Lombrozo talks about why people believe what they do, especially regarding evolution or creationism. Author Steve Miller discusses his new book The Complete Idiot's Guide to the Science of Everything. Plus, we'll test your knowledge of some recent science in the news. Web sites related to this episode include

Podcast Transcription

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Steve: Welcome to Science Talk, the weekly podcast of Scientific American, for the week of April 10th, 2009. I'm Steve Mirsky. This week on the podcast, writer Steve Miller talks about his new book: The Complete Idiot's Guide to the Science of Everything. We'll test your knowledge about some recent science in the news. And first up, cognitive psychologist Tania Lombrozo from the University of California, Berkeley. Lombrozo was a lecturer on the recent SciAm Bright Horizons Evolution cruise. You may recall the March 13th podcast featuring the interview with Jerry Coyne from the cruise. You may also recall the discussion last week of the Texas School Board's problems with evolution education. Lombrozo studies why people believe what they do—specifically about evolution or creationism. We spoke aboard the rocking ship, The Zuiderdam.

Steve: You're doing really interesting work. You've decoupled sort of, "Is evolution true?", you know, "What are problems with evolution?", from people's interpretations of whether or not they accept evolution. Regardless of evolution itself, we're just talking about the psychological profiles of how you come to either accept or not accept evolution. Some of that work is yours and some of it you're very well familiar with from other people; so let's talk about some of the basics and some of the surprises about the people who accept and don't accept evolution and their reasons for it.

Lombrozo: Sure. So I think one of the most surprising findings has to do with the relationship between understanding the basics of evolutionary theory and accepting it as our best account of the origins of human life. So most people, I think, [or] in particular scientists, tend to think that if people reject evolution and in particular evolution by natural selection, it's because they don't understand it very well; they don't really understand what the theory is telling us. But in fact, if you look at the data from psychology and education, what you find is either no correlation between accepting evolution and understanding it or very, very small correlation between those two factors, and I think that's surprising to a lot of people and in particular to educators and scientists.

Steve: Yeah, it was surprising to me when your data were presented. So what [does] that mean for, you know, education in the country? What should people be thinking about if they have a desire to have evolutionary theory be more accepted by more people?

Lombrozo: I think it has a couple of consequences. So, one of them is that any kind of educational intervention that increases people's understanding of evolutionary theory is not necessarily going to have a consequence to whether or not people accept evolution. I think that's surprising, but it also raises a lot of complicated ethical issues; whether or not it's even appropriate in the classroom for teachers to be trying to deliberately influence students' acceptance of evolution as opposed to whether or not they understand it. We normally think about the role of education as being one to communicate basic concepts, to communicate scientific theories, not to actually change whether or not people accept a particular theory that might conflict with their relative views. So I think it raises some complicated issues there.

Steve: So it may be justifiable to say, "Here's what we understand about evolution as a science. We don't care whether you accept it; we just want you to understand it."

Lombrozo: I think that's the way a lot of people think about education, and I think that's a way to sidestep some complicated ethical issues about whether or not it's appropriate to present ideas that could conflict with people's beliefs. On the other hand, people's policy making decisions, their medical decisions and a lot of other decisions might depend not only on whether or not they understand evolution, but on whether or not they accept it. So in some sense, I think the public has a lot at stake in whether or not people accept evolution; but I am not sure the best way to proceed given these kinds of findings about the dissociation between acceptance and belief.

Steve: You had data that broke down people by, sort of, religious background, educational background, economic background; and some of the surprising things there were, for example, somebody might be a fundamentalist Christian but categorize himself as a liberal and have a high education—let's say graduate school—and on average, their acceptance of evolution will be much higher than somebody who is not religious but is low income and only has a high school degree.

Lombrozo: Right, so one of the interesting things is that all of these factors seemed to be correlated to some extent with accepting evolution. So the factors you mentioned—being a fundamentalist or not, not surprisingly perhaps being a fundamentalist is associated with rejecting evolution and level of education; so actually the data that I looked at doesn't look at socioeconomic status directly, but it does look at level of education, which might correlate with that. And you do also find the differences you mentioned based on religious affiliation, and not just how religious someone is but in particular which denomination they associate with.

Steve: Is the acceptance or nonacceptance of evolution a marker for a constellation of other beliefs?

Lombrozo: It definitely does correlate with certain religious beliefs. So, for example, studies pretty reliably find a correlation between how religious someone is and whether or not they accept or reject evolution; in particular, a literal interpretation of Genesis is, [as] you might expect, something that's going to be problematic for accepting evolution. One thing that you don't find is a general propensity for people to have supernatural beliefs. So you might have thought that someone who rejects evolution in general might be more willing to accept supernatural ideas about everything, like the pyramids being created by supernatural forces or...

Steve: ...UFOs

Lombrozo: UFOs or astrology, for example, and you actually don't find a correlation between endorsing creationism or other kind of supernatural, counter human origins and those kinds of traditionally supernatural beliefs aren't associated with Christianity.

Steve: So what's the next kind of stage in this research?

Lombrozo: Well, I think there is[are] several next stages. I think one of the interesting questions, which we're only beginning to understand, is how beliefs about religion can coexist with scientific beliefs. So, in fact, quite a lot of people have no trouble reconciling a belief in evolution with whatever their particular religious beliefs are—and there's a little bit of evidence about how it is that people do this—but it would be interesting to have a greater appreciation for how that process occurs; and that might be research that could push it in the direction of a way of teaching evolution that might not be so problematic for people with different religious beliefs.

Steve: That's [a] really interesting point. So much of the research deals with, or so much of the controversy as well, deals with the extremes whereas the vast majority of people who hold religious views and who accept evolution just, sort of, never get considered because it's not a problem for them. So we really need to understand how they reconcile those things in their psychological lives.

Lombrozo: That's right, and in surveys or questionnaires that have allowed people to, in a more fine-grained way, indicate what their beliefs are, you do find that most people aren't at the extremes where they completely reject evolution 100 percent or completely accept it 100 percent without any kinds of other views about human origin. I think a very common position is something referred to as the theistic evolution; or people think that God is something like the first cause that got the process started and evolution is the mechanism by which God works, and so it would be interesting to have a better sense of what's going on cognitively in people's heads when they have that kind of a view.

Steve: And when we see the polling data that indicate that, for example, only 40 percent of Americans accept evolution, when you throw in the reconciliation that people make between religion and evolution, did the numbers go way up? When you throw in theistic evolution, what kind of numbers do you actually see then?

Lombrozo: Different questionnaires will find different numbers; you do typically find that if you give people that option you get what looks like a larger numbers of people accepting evolution. What gets a little bit tricky is that when you ask people whether or not they accept a position like theistic evolution, you don't quite know what it is that they are endorsing if they say they accept evolution. So you might have people who end up falling into that bucket who think that plants and animals evolved but that humans were created in their present world, for example. Another fairly common view is someone who will accept microevolution—the idea that a given species can change slightly over time—but not macroevolution, the idea that you might get one species from a different species. So you really have to be careful about what it is you are asking people to accept and making sure they understand what it is you're asking them to accept in order to even make assessments of what kinds of views people have.

Steve: And again we are not talking in any way right now about what is really known about evolution. We are, you know, as a science, we are just talking about people's ideas about evolution and their acceptance of whatever it is they think evolution is.

Lombrozo: That's right. One analogy that I find helpful in explaining this is something like the cognitive capacities underlying our ability to understand math. So you could talk about the psychology of our ability to understand math and how it is that we arrive at the belief that two plus two equals four, independently of whether or not two plus two in fact equals four. So I think it is worth saying, this doesn't in any way provide evidence for evolution but it also doesn't give us any evidence against creationism; this is really an independent enterprise.

Steve: Right, although two plus two is four, right?

Lombrozo: That's right, that's right; I used that just to illustrate the point.

Steve: Right. From your research and the research of others you're familiar with, why is something like intelligent design attractive to people, other than a basic kind of religious viewpoint that says that humans are specially created; but why would this whole concept of creationism or intelligent design be something that is attractive to somebody to accept?

Lombrozo: That's a great question. There's actually an emerging literature suggesting that there might be some reasons why humans find particular kinds of explanations especially attractive. For example, the biologist Richard Dawkins writes that humans have purpose on the brain. We seemed to really like explanations that give us some kind of purpose or reason or underlying function for why it is something would have the properties that it has. And one of the things that is interesting about a creationist position, or intelligent design, is that it allows us to provide that kind of explanation for most things. So if you think about the way we explained many biological traits, [like] for example, why do owls have large eyes. It could be that they have large eyes just by chance or as a side effect of some other capacity, but those kinds of explanation seem much less satisfying than an explanation that gives us the function or purpose of having the large eyes; so, for example, that they are for seeing better in dim light, so that owls can catch their prey. And so even though you can give that kind of explanation, [what] you call sometimes a teleological or a teleonomic explanation in evolutionary biology, if you have a creationist or intelligent design sort of position, you're going to be able to explain all aspects of the biological world in that kind of purpose, ever-goal-directed way, and it seems like people find that much more satisfying. And there's a quite a lot of evidence for that now coming both from the preferences for explanations from young children but also from adults, also from Alzheimer's disease patients. So it's really quite a wide range of evidence suggesting that.

Steve: Talk about the Alzheimer's disease patients. Why are you working with Alzheimer's disease patients to look at something like this?

Lombrozo: Right, so let me tell you one bit of background that motivated the study with Alzheimer's disease patients. So there [is] some really interesting research being done by cognitive developmentalists looking at children's explanatory preferences. So what they've done is they've asked children—this is usually pre-school children—a why question and they give them two options for how to respond where only one of those options is what we called teleological, [this] kind of purposive explanation. So for example, you could say, "Why is there rain? Is there rain because water condenses in clouds, or is there rain because that way plants and animals can grow?" That second explanation might sound pretty peculiar to most Western adults, but what you find is that young children seem to overwhelmingly prefer that kind of explanation, suggesting that we might have a widespread preference for these kinds of explanations for the biological world. So that kind of finding has been pretty well documented although still are a little bit controversial like most findings in cognitive development, but it leaves open the question of what happens with adults. So one possibility is that adults also have the same underlying preference for purpos[ive] explanations, which just for whatever reason doesn't manifest as strongly as it does in young children, perhaps because we have a lot more science education. Another possibility is that we outgrow this preference. It could be something that you only see in young children, but then you stop seeing it in adults and beyond. The motivation for looking at Alzheimer's disease patients was that they have some of the characteristics of healthy adults, they have undergone normal cognitive development, they have undergone normal science education, and so on. On the other hand, because of their memory impairments, they may not be able to access the kinds of rich caus[al] beliefs that most adults consult when evaluating explanations. In that sense, they might be somewhat like the preschoolers who haven't yet acquired certain kinds of scientific beliefs. So looking at the Alzheimer's patients allows us to see whether or not you see that population falling back on this kind of preference for purposive explanations in the absence of the kinds of alternatives that most healthy adults have available, like the idea that rain results from water condensing in clouds. In fact, what you find is that if you do a task like the one I described with preschool children with the Alzheimer's disease patient's—so [if you] ask them, "Why is there rain? Is there rain because water condenses in clouds or is there rain so that plants and animals can grow?"—they will also prefer the teleological option much more often either than healthy young adults or their age matched controlled participants who are the same age as the Alzheimer's patients but don't show signs of Alzheimer's.

Steve: It's really interesting. And let's also point out—[I mean, you sort of mentioned it very briefly—that people who fully accept evolution may still have a teleological bent to their acceptance; they are extreme adaptationsts. So that when they are asked, you know, why does an elephant have a long trunk, it's always a reason as if the trunk evolved because there was a purpose that it had to get to eventually, which was to reach the food in the high tree and bring it down to the elephant's mouth. Maybe that's not such a great example. Let me think of another one. Well, you give me another one.

Lombrozo: Well, I was going to say it's definitely the case that a lot of people have misconceptions about natural selection, and one of their most common is to think about it as a goal-directed process; that the elephant is really trying to get a longer trunk to reach food or a giraffe is really trying to reach further food and that's going to result in a longer neck. What's interesting is...

Steve: That's the classical Lamarckian evolution.

Lombrozo: Right.

Steve: But even people who are natural selection evolutionists can still fall into the adaptationist trap.

Lombrozo: Right, so this actually corresponds to a famous debate in evolutionary biology between people like Dawkins on the one hand, who are sometimes labeled adaptationists and people like Steven Jay Gould and Richard Lewinton on the other hand, who really emphasize that there is a lot of evolutionary forces that work. Natural selection is only one of them; and so something can end up with a particular set of properties because it's the result of genetic drift or because it's the side effect of another kind of capacity. And so if you have this drive towards these kinds of purpos[ive or] teleological explanations, then even within evolutionary biology you're going to be drawn towards these very heavily selectionist, adaptationist kinds of explanations, like the example you gave or saying that owls have large eyes in order to see in dim light. The, kind of, extreme case of that is something that['s] sometimes invoked in the debate between people like adaptationists like Dawkins and anti-adaptationists is why we have noses—for holding up our glasses, right?

Steve: Right.

Lombrozo: So that's the case where we know that that's clearly not a good evolutionary explanation, but that kind of drive to find a function for everything is something that characterizes a lot of contemporary evolutionary biology. And there's an open debate about whether or not it's a good strategy for trying to end up with the best evolutionary accounts of current biological findings.

Steve: Right. So we have to be really careful when you analyze a trait in its current environment just to really see whether it evolved for a particular purpose or it's just some kind of an artifact of evolution.

Lombrozo: Exactly.

Steve: Interesting stuff, thanks very much.

Lombrozo: Thank you.

Steve: Steve Miller is a freelance science writer. I ran into him at the AAAS meeting in Chicago in February and we spoke briefly about his new book. Steve Miller, you have written The Complete Idiot's Guide To...

Miller: ... The Science of Everything.

Steve: Everything?

Miller: Well actually it's not everything in science, but it covers a broad range, and we're looking at questions from many different fields: physical, earth science, biology.

Steve: So who is this aimed at? Complete idiots apparently.

Miller: No, I think the complete idiot is the person that wrote it, but it's geared toward anyone that has an interest in science and wants to answer questions that may have been lurking about. The initial one, which shows up very frequently in books like this as why is the sky blue, while the other questions are why does popcorn pop? Why are some genetic diseases more common in men than women? [A] wide range of questions that I just found interesting and had a good time answering.

Steve: [Is] this kind of book you read from beginning to end or do you just pick it up and open it [at] random and see what jumps out at you?

Miller: No, actually it's the perfect book for reading on a train or sitting around when you have five minutes, because each question is self-contained; you just spend two or three minutes on it and set it down and hopefully go back to it again.

Steve: So let's throw our cards on the table here. It's the perfect bathroom book.

Miller: You've got it.

Steve: So what did you wind up, I mean, you allege you were a complete idiot when you went in, and you're obviously very educated coming out of this process of writing this book? Give me a couple of the things that you were absolutely flabbergasted to learn as you wrote the book.

Miller: That one is a question of, Why do flu epidemics seem to start in Asia all the time? They always seemed to talk about the Hong Kong flu or the China flu or different things, and as I looked into it, I found that there were a couple of reasons. One is that many flu viruses come from birds and get transmitted to people from other species; you get a change in the virus and suddenly it jumps to humans. And in many Asian cultures, people live closely with their domestic animals, including a lot of birds, ducks, chickens and such, and the other thing is just there are so many people in Asia and the concentration of people is so great that you tend to get spread of a disease very quickly once it starts, and the two things combined lead to the flu coming out of Asia.

Steve: So the environmental conditions are really a good incubator [for] this process of creating new and potentially more-potent flu viruses.

Miller: That's right. It's the perfect environment for a new pathogen to start and get from one place to another very quickly.

Steve: Give me another one. What else did you find out as you were—and how did you pick what topics to cover in the science of everything? I mean, obviously, that book could have been as big as you wanted it to be.

Miller: Well actually that was a big part of the process of writing it, is deciding the questions, because there are thousands and I can only [fit] about 200 or [a] little more; but these are all the questions that I find interesting.

Steve: So do you have room in there for any, for example, quantum mechanics in the book?

Miller: Yes, in addition to the answers to the questions, there are several chapters on what is science, what's a theory, what's new in science, and that's where quantum mechanics fits in, where are we going with it?

Steve: New aspects of quantum mechanics, because quantum mechanics itself is 100 years old.

Miller: Right, this is really not intended as a textbook, it's just a fun book to read.

Steve: Is this aimed at any particular age group or is it anybody over, say eight-years-old, who is interested.

Miller: Essentially anybody from middle school on. It's probably a little bit in-depth for elementary school students but once you get to middle school, you should be able to read it and find it fascinating, and I hope that it's very fascinating for adults as well.

Steve: And hopefully it's the Complete Idiot's Guide to the Science of Everything, Volume I.

Miller: That's fine...

Steve: Now it's time to play TOTALL....... Y BOGUS. Here are four science stories; only three are true. See if you know which story is TOTALL....... Y BOGUS.

Story number 1: Some people drive over baseball bats to try to enhance them.

Story number 2: Studies show that professional golfers have more slow-twitch muscle fibers than nongolfers.

Story number 3: Agricultural scientists have determined that salmonella only evolved the ability to infect the interior of a hen's egg within the last 40 years.

And story number 4: Male chimps who offered meat meals to females doubled their long-term chances of mating with those females.

Time's up.

Story number 1 is true. In the brave new world of nonwooden bats, some people go to extremes to try to improve the bat's performance. So called doubled-walled composite bats give you a spring effect, so driving over the bat or hitting it with something else may further separate layers and increase the trampoline effect; or you could learn to hit the curveball.

Story number 4 is true. Male chimps who gave females meat dinners did indeed double their long-term chances of mating. For more, check out the April 8th edition of the daily SciAm podcast, 60-Second Science.

And story number 3 is true. Using whole-genome mutational mapping, agricultural researchers found that two salmonella strains hybridized about 36 years ago, and the hybrid result gained the ability to move from the hen's reproductive organs to the interior of the egg. The hope is that studying the infectivity may help scientists figure out ways to reduce it. They should also consider evolutionary principles in the entire factory-farm situation of thousands of animals in close quarters, so as to be able to avoid such problems in the first place. In a related story, the CDC announced on April 9th that food safety has stopped improving and that salmonella is fighting efforts to control it better than any other food-borne illness.

All of which means that story number 2, about great golfers having more slow twitch muscle fibers is TOTALL....... Y BOGUS. But what is true is that they probably have more gray matter in their brains, according to our buddies at Live Gray matter, which is densely packed nerve cells, is related to muscle control, so the pro-golfers probably develop the gray matter through thousands of hours of practice rather than having it to begin with. Remember, as you watch the Master's this weekend: You drive for show, but you [put for dough].

Well, that's it for this edition of Scientific American's Science Talk. Check out for the latest science news, and our In-Depth Report on the science of our food. For Science Talk, I'm Steve Mirsky. Thanks for clicking on us.

University of California, Berkeley, psychologist Tania Lombrozo talks about why people believe what they do, especially regarding evolution or creationism. Author Steve Miller discusses his new book The Complete Idiot's Guide to the Science of Everything. Plus, we'll test your knowledge of some recent science in the news. Web sites related to this episode include

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