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Evolutionary Psychology under attack
Author Paul Kenyon
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Topic overview

This topic covers some fairly demanding material. You may find it useful to do the three 'warm up exercises' before tackling the more advanced material. They are designed to show you that you already have a reasonably clear understanding of evolutionary psychology by this stage of the module.

Darwin's writings on evolution have spawned two fundamentally different types of controversy.

It is very important to appreciate and keep these two controversies separate in your mind. Most of this seminar focuses on the second type of controversy - the debate between scientists on the role of selection in the evolution of human behaviour

We begin with a series of videos showing that the theory that animal species evolve is controversial. I encourage you to view this material before attending the seminar because it illustrates just how sensitive this issue is, even today. If you don't have a high speed internet connection, borrow a pair of headphones and use a campus computer to view the videos.

I have included a section on work by contemporary historians and philosophers of science which seeks to unravel cultural influences on Darwin's work. This should help you appreciate current controversies over evolutionary theory as a paradigm for psychology.

The main thrust of this page is to consider contemporary attacks on evolutionary psychology by biologists and social scientists. I have chosen two examples to illustrate the intensity of feeling sparked by the claim that some aspects of human behaviour may be the result of natural selection:

I use Gould's 1997 article in the New York Review of Books :"Evolution: The Pleasure of Pluralism", to illustrate the raw intensity of the debate. This article provoked a savage response from Tooby and Cosmides - you can judge the merits of both sides of the argument for yourself. John Alcock's response to Gould's attack is somewhat more restrained and alludes to the four types of question that can be asked about a behaviour. These were laid out by Niko Tinbergen and I have used them as a 'framework-of-sanity' in this module.

If you want to delve deeper into this topic, Brown (2000) and Ruse (1999) provide informative, revealing and entertaining accounts of the passions that are aroused by recent attempts to explain aspects of human behaviour in terms of natural selection.

We then move on to consider a much more carefully judged - but boldly titled - critique of evolutionary psychology by Panksepp & Panksepp: "The seven sins of evolutionary psychology". I found plenty to think about in this article.

Finally at the end of the seminar we explore just how difficult it is to construct a good theory by constructing our own theory of the evolution of behaviour.


Warm-up exercises

These  'warm up exercises' are designed to show you that you already have a reasonably clear understanding of evolutionary psychology by this stage of the module.

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Klimt's 'Tree of Life'
Exercise# 1 Points to ponder

The Greek philosopher Aristotle viewed animals as positioned along an ascending linear scale (scala natura) with humans at the top of the scale. Nowadays all biologists reject this linear concept of species. It was firmly driven out of psychology by Hodos and Campbell in their 1969 paper "Scala naturae: Why there is no theory in comparative psychology." Nevertheless, I suspect there are still remnants of the scala natura in the popular imagination with a tendency to view humans as 'more-highly-evolved' in some way compared to the rest of the animal kingdom. Do you think remnants of this type of thinking may subtly influence attitudes to animal rights across species, race and social class?: In a  famous English comedy sketch,  a tall, upper-class John Cleese looked down on a mid-height, middle-class Ronnie Barker, and they both looked down on a small, lower-class Ronnie Corbett.

You might find it useful to listen to this radio programme chaired by Melvyn Bragg between Pinker, Richards and Gray in which they discuss if there is really such a thing as human nature.

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Michaelangelo's   David

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Exercise# 2 Questions to think about:
  • Are human beings animals?
  • Have modern humans evolved from chimpanzees?
    • Jane Goodall talks to the BBC about chimpanzees in this  video
    • the Scientific American Frontiers video (2001) "Chimps Observed" describes Goodall's work, gives very good reasons why you should abscond from university ASAP, and mentions the issues raised by scientific observations that may have direct implications for how we view our own species.
    • the Scientific American Frontiers video (2001) "Chimp Nations" discusses culture in chimps
    • Scientific American Frontiers video (1995) "Monkey See, Monkey Do"  discusses differences in imitation learning in primates and humans
    • Sir Neil Chalmers lectures on "Monkeys and Apes:Are they nearly human?"  in this Darwin Centre: Natural History Museum video (2003)
  • Do human beings represent the 'end-point' of evolution?
  • Has human behaviour evolved?
  • Will people in the future be more intelligent, attractive, longer-lived, less disease-prone etc?
  • Will authoritarian states evolve into democracies?
  • Will 'primitive tribes' evolve? What does the phrase 'primitive tribe' mean?
  • How do you react to the words of the famous hymn:

    "All things bright and beautiful,
    all creature great and small
    ,
    all things wise and wonderful,
    the Lord God made them all."

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Exercise# 3 Test your wits with the experts!

In 2002 the BBC broadcast a series of programmes entitled Human Instinct. The last programme was followed by a studio debate that you can review online. The debate was chaired by Joan Bakewell with contributions from Winston, Dunbar and Pembrey who are clearly 'thinking on their feet' in response to viewers question on the influence of 'nature and nurture' on human behaviour.

Imagine that you are a TV researcher sitting in the control room with audio contact between you and each of the studio experts. Your job is to 'feed' comments and suggestions to these experts as they respond to viewers questions. How could you help our experts by drawing on your knowledge of:

  • 'preparedness';
  • the influence of 'culture' on taste preferences;
  • fear and the amygdala;
  • the development of behaviour;
  • gender differences and  sexual selection;
  • long and short-term mating strategies;
  • self-sacrifice and altruism (a clue for the Vietnam story may be contained in the phrase 'brothers in arms');
  • the passions raised by 'biological/genetic/nature' views of human behaviour;
  • the conflict between religious and evolutionary/biological views of human nature;
  • the nature of proof in the early and later stages of development of scientific theory;

There are some good examples in this programme of the difficulties experts can get into when trying to explain to a lay audience 'single case behaviour-of-unknowable origin' questions which often take the form "Why does my cat/dog/granny ...". In addition some questions refer to very complex issues that are very difficult to answer in the 'quick-fire' style needed to create an interesting TV debate.

Could you detect any issues that provoked tensions / grandstanding between the panelists? One way to spot this is to imagine what the other panelists might be thinking when one of them is responding to a question.

You can also watch Professor Robert Winston answer viewers questions before the series "Human Instinct" was broadcast on Breakfast TV  on 22 October, 2002


Darwin's theory of evolution in a nutshell

  • Reading Malthus' "An Essay on the Principle of Population", Darwin was struck by the fact that all organisms produce considerably more offspring than are needed to replace the parents. For example, a pair of spawning salmon are estimated to produce 5,000 fertilized eggs, if all these eggs developed into adult salmon our rivers would be choked with salmon. Clearly there is massive mortality between egg and adult organism.
  • Despite this tendency to a progressive increase in numbers, the numbers of a given species remains more or less constant
  • From these two factors it follows that there is a 'struggle for existence' - some offspring survive, others perish
  • Offspring are not 'carbon-copies' of their parents; there is widespread heritable variation
  • Darwin suggested the novel idea that the fittest tend to survive, the unfit perish
  • Consequently this leads to adaptive improvement over the generations - evolution
Frequently Asked Questions (FAQ):

The battle between creationism and evolution

If you were educated in a British school you are probably not aware that nowadays the teaching of evolution is very controversial in some some American states.  Here is a set of videos that show that evolution was born in controversy, and continues to arouse strong feelings.  
  • Begin by reviewing the PBS video Darwin: Reluctant Rebel in which "James Moore explains that Darwin developed his theory of evolution by natural selection at a time when creationism dominated the public thinking. In this clip, Darwin is seen arguing for his theory with creationist thinkers, including the H.M.S. Beagle's Captain FitzRoy, his colleagues, and even with his own wife Emma. Philosopher Daniel Dennett explains that humans naturally want to believe that there is some purpose to the universe, and prefer to think of themselves as "special," rather than just another species in the animal kingdom. "
  • View the PBS video "Courtroom Controversy" which is available online in order to get an insight into the long running battle between creationism ("the religious doctrine that all living things on Earth were created separately, in more or less their present form, by a supernatural creator, as stated in the Bible") and evolutionary theory in America. What is at stake is the right to teach evolutionary theory and creationism in American schools.
  • View the PBS video "Ken Ham: Biblical Literalist" which is available online and gives a very clear insight into creationist teaching in a religious context.
  • View the PBS video "Teaching Evolution Case Studies: Dealing with Controversy" which is available online and shows how teachers have dealt with the controversy surrounding teaching evolution in American schools in the last decade.
  • Although teaching children that plants and animals evolved has not generated widespread controversy in British schools, Emmanuel College, Gateshead, was recently in the news for teaching creationism to its pupils along with evolution. This was the subject of a BBC radio programme
  • Do you think children should be taught evolution in British schools?

 

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Is Darwin's theory free of 'cultural values'?

In recent years a 'Darwin industry' has developed involving historians attempting to understand, unravel, and interpret the cultural influences on Darwin, and Darwin's influence on culture. There is very clear coverage of the cultural context, impact and scientific merits of Darwin's theory in:

  • Bowler (2000) "Charles Darwin: The Man and his Influence", University of Cambridge, Cambridge, Chapter 1 "The Problem of Interpretation".
  • Patterson (1999). Evolution, 2nd Edition, Cornell University Press, New York. Chapter 14 "Proof and disproof; science and politics".
  • Ruse (1999). "Mystery of Mysteries: Is Evolution a Social Construct?". Harvard University Press, Cambridge, Mass. Chapter 3 "Charles Darwin"

When Darwin published his theory of evolution in 1859 it generated less controversy than we are sometimes led to believe. On the contrary, it was generally welcomed. Darwin's theory did not come as a 'bolt out of the blue' to an unsuspecting audience. In fact, Darwin was not alone in proposing a theory of evolution. There were already several accounts of evolution, but they were fundamentally different to Darwin's.

darwin-mirror-monkey.jpg (68611 bytes) Pre-Darwinian theories postulated that evolution was the progressive unfolding of a purposeful plan involving a linear trend of increasingly complex species that culminated in the appearance of humans i.e. the natural world was considered to be a scala natura. These were evolutionary theories - in the sense that they rejected the picture of creation presented in the Book of Genesis - but they allowed space for God to operate as the master planner of a gradually improving world. But careful reading of Darwin's theory shows that it does not admit a purposive plan, and does not imply that humans occupy the highest rung on an evolutionary ladder. Instead it suggests that the mechanism underlying evolution involves random variation between individual members of a species being fed into a filtering mechanism composed of environmental pressures.

Evolutionary theories were welcomed by some in the mid nineteenth century; they offered a progressive way forward for a society dominated by church and aristocracy. But they were treated with suspicion by others because they threatened to abolish the special place of Man in the natural world, and disrupt a relatively stable social structure that had seen fundamental political upheavals in nearby France. Perhaps Darwin's theory of evolution was better adapted than others to survive in the scientific and social environment that existed in England nearly 150 years ago.

Bowler suggests that in 1859 readers interpreted the main message of the Origin of Species in line with the cultural beliefs of their times:

  • They paid little attention to Darwin's theory that evolution relied on natural selection as the mechanism for change, and focussed instead on an evolution powered by Lamarkism, orthogenesis or a divine plan.
  • They held to the mistaken belief that evolution produced progress along a preordained path as a result of "the struggle for existence" and the "survival of the fittest", to attain the 'highest point' of evolution - mankind.

Darwin may have colluded with this misinterpretation to facilitate popular acceptance of his theory. Ruse (1999) argues that Darwin believed in social progress and this is increasingly evident in later revisions of the Origin of Species. For example, in the third edition published in 1861 he wrote that "natural selection clearly leads towards highness" (see Ruse 1999, p69-70).

Furthermore, Darwin seems influenced by the values of his social class, upbringing and circle of acquaintances. Ruse points out that in Darwin's book on human evolution - The Descent of Man - published in 1871, "Darwin brought in all of the cultural values of his sex, race and class. Not only do we learn that men are string and brave and brainy, whereas women are kind and gentle and sensitive; that whites are intelligent and hardworking whereas blacks are stupid and lazy; but that, on the whole, capitalism is no bad thing."

Darwin was highly respected during his lifetime - both before and after publication of the Origin of Species - and this is reflected in his resting place: He was buried next to that other national scientific hero, Sir Isaac Newton, in Westminster Abbey in 1882. And his fame lives on: In 2002 Darwin was voted fourth in a poll of the most important Britons of all time in a national survey organized by the BBC. He was beaten by Churchill, Brunel and Princess Diana.

But you are now faced with a problem. Should you criticize Darwin's theory because it was tainted by cultural factors from an earlier period of our history? Or do you accept that Darwin, like all of us, is a product of our time and culture, but nevertheless he had an important insight into a reality that exists independently of time and culture?

Reading Ruse (1999) Chapter 1 "Karl Popper and Thomas Kuhn: Two Theories of Science" may help resolve this dilemma. The power of Ruse's (1999) evaluation of Darwin's influence comes from his analysis of:

  • the epistemic values of Darwin's theory together with a
  • consideration of non-epistemic factors surrounding evolutionary theory

Epistemic values or "scientific values" are a set of characteristics of a scientific theory that reveals a reality that - we assume - exists outside ourselves, and exists independently from us (i.e.' truth'). Ruse draws on work by McMullin to draw up a list of epistemic characteristics or "scientific values" which include:

  • predictive accuracy - the ability to forecast what we have not yet observed
  • internal coherence - the various parts of the theory should not contradict each other
  • external consistency - the theory should not contradict other accepted theories, or 'laws of nature'
  • unifying power - the theory should bring together and explain previously disparate areas of knowledge
  • fertility - the theory should generate novel hypotheses
  • falsifiability - it should be possible to construct hypotheses that could lead to the rejection of the theory - this is an especially important scientific value
  • simplicity and elegance - this is a value judgement i.e. it is a subjective judgement made by scientists. Consequently simplicity is a desired characteristic rather than a defining characteristic of a scientific theory.

Non-epistemic or "cultural values" factors refer to

  • factors in our culture that persuade us to construct a theory of reality based on our cultural experiences
  • the feedback-influence of scientific theories on our culture
Here is an example of  theory construction and the scientific method applied to a current problem.

Examination of the Darwin's life and times shows the influence of non-epistemic cultural values on the genesis of his theory, and particularly its development by his disciples. Furthermore, the epistemic qualities of evolutionary theory has had a powerful feedback effect on cultural values in the last century. For example, the use of metaphor such as Dawkin's 'selfish genes', and value-laden phrases such as 'survival of the fittest' (which was adopted by Darwin from Herbert Spencer), and "the struggle for existence" have entered the popular imagination.

When it was first published, Darwin's theory was not as epistemically strong as it is now. Ruse provides a convincing case that Darwin's theory contained several epistemic weaknesses:

  • The theory made few short-term predictions that could be objectively measured to enable falsifiability
  • Contemporary estimates of the earth's age did not allow enough time for evolution to have occurred
  • Darwin found it difficult to account for the evolution of sterile insects
  • Darwin did not provide a convincing explanation of how characteristics were passed from generation to generation
  • But Darwin's theory triumphed in its ability to unify information from separate areas of biology
  • And. We now know that the earth is older than first suspected. Mendel's work provided the 'missing' mechanism for heredity.

Evolutionary theory now forms the paradigm for the biological sciences. A paradigm is a body of theory, results, methods, and set of acceptable questions that are embraced by the vast majority of people working in a particular discipline. It is a generally accepted way of doing science (see Ruse 1999, p19). You may be wondering what paradigm binds together all psychologists. I can't give you the answer.

I started my undergraduate studies in Zoology, Physiology and Botany so was immersed in the evolutionary paradigm from a tender age. But then I switched to psychology where a favorite student-discussion question used to be "Is psychology a science". I used to thoroughly enjoy arguing with friends that 'psychology is a pre-paradigmatic junk yard full of cognitive scrap metal'. Read about Thomas Kuhn's views on scientific paradigms in Ruse Chapter 1 if you want to continue this time-honored student drinking game.

Additional reading:

  • Kohn (2002) review of "Charles Darwin: the power of place" by Janet Browne in The Independent newspaper, 16 November 2002, available online 
  • Marr (2002) Darwin: Andrew Marr's Greatest Briton broadcast by BBC TV. Video clip and web page supporting  the programme

Here is an example of  theory construction and the scientific method applied to a current problem.


In order to gain a deeper understanding of contemporary evolutionary theory you might find it useful to read parts of Colby (1996) "Introduction to Evolutionary Biology" in The Talk.Origins Archive which is available online. You might like to consider the following points which are covered in the first nine pages of the article:

Read the section "The Development of Evolutionary Theory" in Colby (1996) and consider the following points:

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Lamark

  • Compare and contrast Darwin and Lamark's view of evolution. Lamark's ideas on evolution found favor in Russia under Stalin in the 1930s and '40s because they meshed neatly with Marxism and promised the birth of better citizens through parental striving to meet the soviet ideal. According to the geneticist Lysenko the ability to withstand harsh environments would be inherited from parent stock that had been exposed to these conditions. (See Gaglioti (1996) The fate of Soviet genetics).
  • Why is the idea of 'blending inheritance' wrong, and impossible to reconcile with evolution via natural selection?
  • Colby (1996) states that "Mendel mailed his paper to Darwin, but Darwin never opened it". I don't know if this is true but Mendel does not appear in Darwin's biography written by Desmond and Moore (1991), and according to Boakes (1984) , Mendel's work on the inheritance of the characteristics of peas was lost until 1900.
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Stalin

Read the section "Scientific Standing of Evolution and its Critics" in Colby (1996). Do you agree with Colby's dismissal of scientific creationism?


To what extent has human behaviour evolved?

Darwin was very restrained when he wrote the Origin of Species. It is only in the final pages of the book - after he had presented the theory of evolution of plants and animals by natural selection - that he made his views on the evolution of human behaviour clear: He wrote:

"In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation."In other words Darwin believed that human behaviour was subject to natural and sexual selection. It also suggests that Darwin was particularly interested in humans and the evolution of human behaviour.

victorian-women.jpg (3326 bytes)leighton-painting.jpg (3165 bytes)Reading about Darwin, I get the impression that these underlying interests were suppressed due to the political and social climate in which he lived ( e.g. Abrams (2001) "Ideals of womanhood in Victorian Britain"available online)


Point to ponder

View  this video (authors@MIT 2002) in which Steven Pinker discusses his book "The Blank Slate: The Modern Denial of Human Nature".

Do you think contemporary psychology is based on the foundation anticipated by Darwin in 1859?

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Pinker

And it's not only in 19th century England that Darwin's thoughts are considered shocking. As we shall see the application of this view by evolutionary psychologists is not very popular with some contemporary biologists and psychologists. Read the Pinker vs. Rose debate which is available online and consider the following points.
  • What is the main message in Pinker's book "How the Mind Works"?
  • Are Pinker and Rose creationists?
  • Do Pinker and Rose believe that the ways things are is the way things should be?
  • Do Pinker and Rose believe that our behaviour is a product of nature or nurture?
  • What do Pinker and Rose believe is the function of an individual's life?
  • Do Pinker and Rose believe that behaviour is controlled by a soul?
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Rose

Read the reactions by Pinker and Rose to each other's presentation ( see The Pinker vs. Rose debate, Part 1 page 5) and consider the following points:

You may find it useful to read Curry's response ( which is available online ) to the Roses' attack on evolutionary psychology in their book "Alas, Poor Darwin" published in 2000.

Curry (2003) discusses


The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme

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Stephen Jay Gould obituary

Obtain a copy of Gould and Lewontin (1979). "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme." Proceedings of the Royal Society of London, Series B, Vol. 205, No 1161, pp. 581-598, available online

This is a complex paper written by biologists for biologists, and may not be easily understood by scientists without a first / higher degree in biology. We will concentrate on those parts of the paper that formed the basis for Gould's attack on evolutionary psychology.

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Richard Lewontin

What do the terms 'spandrel' and 'Panglossian paradigm' in the paper's title mean?

Spandrel (or pendentive) is the triangular area between two curved arches in buildings. These areas are often used to house elaborate paintings or carvings which are precisely designed to fit into the available space. It is obvious that these decorations have been placed within spandrels to cover an otherwise bare section of the buildings. No one would argue that the building was constructed with curved arches in order to leave spandrels that could be decorated. The spandrel arises because of an architectural constraint. The spandrel is a consequence of the way the building was constructed. A spandrel provides a blank area for an artist to exercise their imagination. Here are examples of that exercise of imagination: image 1; image 2

Gould and Lewontin argue that features of an animal's body and behaviour may have developed for the same reason as spandrels. These spandrel-features are consequences of true adaptations of the animal's body and behaviour which truly evolved under the pressures of natural and sexual selection.

Panglossianism refers to the search for an adaptive reason for every aspect of an animal's behaviour. Panglossianism ignores the possibility that some features of body and behaviour may be spandrels. Gould and Lewontin detected traces of Panglossianism in evolutionary psychology. Panglossianism is named after Dr Pangloss, an eternal optimist in Voltaire's book Candide. He believed that everything was for the best, in the best of all possible worlds. Panglossian explanations are simply the exercise of creative imagination over careful experimental investigation, for example our noses evolved to support spectacles as we grow older; earlobes evolved to support earrings, or benzodiazepine receptors evolved in the brain so that anti-anxiety drugs such as Librium and Valium would have somewhere to attach to. voltaire-wedgwood.jpg (3124 bytes)

Voltaire

In the paper find Section 5. "A Partial Typology of Alternatives to the Adaptationist Programme": Go to the last paragraph of Subsection 3 "The decoupling of selection and adaptation", and read the paragraph beginning "Adaptation" - the good fit of organisms to their environment - ..."
This paragraph contains the essence of Gould and Lewontin's criticism of Sociobiology (the forerunner of evolutionary psychology. Look up 'adaptation' in the glossary of this page.

Read the abstract at the start of Gould and Lewontin's paper and consider the following points:

Feel free to read the rest of Gould and Lewontin's paper. Do not be put off if there are unfamiliar biological terms. Remember that the paper is directed at biologists who use the adaptationist programme to guide their research in areas you will not have encountered before, and do not relate directly to evolutionary psychology (e.g. tyrannosaurus legs). Here are some highlights:

Here is a little story I tell myself to explain genetic drift and Gould and Lewontin's critique of the adaptationist programme:

Two rats with short corkscrew tails met, fell in love, and decided to elope. They boarded a cruise liner and disembarked onto an uninhabited island where they wed and prospered. After that, ships seldom visited the island which was overrun with rats.
Several years later two adaptationists visited and pondered .... Eventually they stopped an inhabitant and - pointing to his tail - asked "What's it for?".
"Nothing, great-grandfather and great-grandmother were born this way and there seems no good reason to abandon tradition" came the reply.
Missing the point, the scientists stayed and the island is now populated by men with long beards and women in blue stockings who wander about pointing at this and that asking, "What's it for?".
Recently, a professor of evolutionary psychology at the island's university ordered several cases of fine wine - he has an idea !

Well, it makes sense to me ...

Read Section 6 "Another, and Unfairly Maligned, Approach to Evolution" in Gould and Lewontin.


If you have persisted with this set of readings you should now be in a good position to appreciate the sometimes vicious exchanges between Gould and a number of leading evolutionary psychologists.

You should have sufficient background knowledge to appreciate Gould (1997) "Evolution: The Pleasure of Pluralism", New York Review of Books, June 26, 1997 which is available online. As you work through the article you could retain the following issues in mind:


Read Tooby and Cosmides (1997). Letter to the Editor of New York Review of Books on Stephen Jay Gould's "Darwinian Fundamentalism" (June 12, 1997) and "Evolution: The Pleasure of Pluralism", (June 26, 1997) available online


Read Alcock (2000). "Misbehavior: How Stephen Jay Gould is wrong about evolution. Boston review, April/May 2000 (available online)  for a response to Gould and Lewontin's attack on the adaptationist programme by an evolutionary psychologist / sociobiologist.

Here are some points for you to consider:

Alcock accuses Gould of favoring 'proximate explanations' over explanations based adaptive or reproductive value of behaviour. Does Tinbergen's explanation of the four ways that the question "Why ?" can be posed provide a way out of this controversy?
You are probably familiar with the fact that the clitoris and glans penis develop from the same tissue under the influence of hormones. Is it worth exploring an adaptive function for female orgasm?

Can you point to any advances in understanding human behaviour that have been made by evolutionary psychologists utilizing the adaptationist programme?


Acquire a copy of  Buss et al. (1998). "Adaptations, exaptations, and spandrels", local copy available here. This is an extremely well written and useful paper. I found it helped to read pages 533-539 even though it reviews material we have encountered already. Alternativly, you may want to begin at the section "Exaptations and Spandrels" on page 539

If you want to delve deeper into this topic, Brown (2000), Ruse (1999) and Morris (2001) provide informative, revealing and entertaining accounts of the passions that are aroused by recent attempts to explain aspects of human behaviour in terms of natural selection.


"The seven sins of evolutionary psychology"

Read Panksepp & Panksepp (2000). "The seven sins of evolutionary psychology". Evolution and Cognition, vol. 6 no 2, 108-131 which is available online.

This is an important paper because it goes beyond the type of criticism of evolutionary psychology you have come across already. For example, some commentators argue that evolutionary psychology relies on 'Just so' stories. The Panksepps put forward the potentially more fruitful criticism that evolutionary psychology tends to be 'anthropocentric' and ignores research carried out on other mammals.

As you read the paper consider the following issues:


Evaluation of evolutionary psychology as a theory of human behaviour

You have now been exposed to a considerable body of discussion, comment and argument about the strengths and weaknesses of evolutionary psychology as a paradigm for psychology. Now may be a good time to step back from all the detail and ask a simple question:

Do Cosmides and Tooby provide a evolutionary psychology a good theory of human behaviour?

You have already seen that Ruse (1999) distinguishes between two characteristics of a theory:

  • the epistemic or 'scientific values' values of a  theory
  • the non-epistemic or 'cultural values' of a theory

Epistemic values or "scientific values" are a set of characteristics of a theory that reveals a reality that - we assume - exists outside ourselves, and exists independently from us (i.e.' truth'). Ruse draws on work by McMullin to draw up a list of epistemic characteristics or "scientific values" which include:

  • predictive accuracy - the ability to forecast what we have not yet observed
  • internal coherence - the various parts of the theory should not contradict each other
  • external consistency - the theory should not contradict other accepted theories, or 'laws of nature'
  • unifying power - the theory should bring together and explain previously disparate areas of knowledge
  • fertility - the theory should generate novel hypotheses
  • falsifiability - it should be possible to construct hypotheses that could lead to the rejection of the theory - this is an especially important scientific value
  • simplicity and elegance - this is a value judgement i.e. it is a subjective judgement made by scientists. Consequently simplicity is a desired characteristic rather than a defining characteristic of a scientific theory.

How do you think evolutionary psychology measures up against these criteria? Non-epistemic or "cultural values" factors refer to

  • factors in our culture that persuade us to construct a theory of reality based on our cultural experiences
  • the feedback-influence of scientific theories on our culture

Do you think cultural values have helped shape evolutionary psychology?Do you think evolutionary psychology will shape culture?Do you think there are any similarities between the genesis and early development of Darwin's evolutionary theory and evolutionary psychology?


The Theory of Evolutionary Psychobiology

This section gives an insight into just how hard it is to construct an evolutionary theory of behaviour. Lets try to construct a novel theory by returning to the basic ideas used by Darwin in his theory of evolution:

mandelbrot-set.jpg (3016 bytes)Our theory - let's call it evolutionary psychobiology to distinguish it from evolutionary psychology - suggests that the principles that govern the evolution, development and expression of different behavioural modules are identical to the principles that govern the evolution, development and expression of different species.

Let us for the sake of argument make two assumptions:

What we know about species What we theorize about behavioural modules
british-bird-stamps.jpg (17390 bytes)Species have a physical reality which enables them to be distinguished from each other. dopamine-pathways.jpg (9275 bytes)Behavioural modules have a physical reality involving cells and neurotransmitter systems within the brain, but at present are most easily distinguished from each other in terms of their behavioural 'output' e.g eating and fighting are the products of discrete behavioural modules. However, modules can impart a 'quality' to behaviour e.g. ritualization (BBC, 2003, Ritual).
Several discrete species make up an ecosystem Several discrete behavioural modules make up a brain and nervous system.
Similar but discrete ecosystems contain the same species e.g. it is reasonable to assume that a 10 acre field one mile east of my village contains the same biodiversity as a 10 acre field one mile west. Similar but discrete individuals contain the same behavioural modules e.g it is reasonable to assume that you and I eat, drink, sleep and occasionally make love.
Individual members of a species show variation as a result of the continuous influence of genetic, environmental and random factors. An individual's behavioural modules vary as the result of the influence of genetic, environmental and random factors on the continuous development of each behavioural module.
Species evolve through natural and sexual selection. Behavioural modules evolve through natural and sexual selection
Species can evolve independently of other species Behavioural modules can evolve independently of other behavioural modules
Species can co-evolve with other species Behavioural modules can co-evolve with other behavioural modules
Species are discrete, but can interact with each other e.g. sharks and cleaner fish are discreet species but they interact Behavioural modules are discrete, but can interact with each other e.g. eating depends on eye-hand co-ordination.
The functioning of a particular species may be dependant on the normal functioning of other species e.g. a decline in prey may lead to a decline in predators The functioning of a particular behavioural module may be dependant on the normal functioning of other co-dependent behavioural modules e.g fear may lead to a decline in sexual motivation
We can control the impact of a particular species within an ecosystem e.g. pest control. We can potentially control the influence of behavioural modules through psychological and/or physical intervention.
Serious depletion of a species within an ecosystem has unpredictable effects and may destabilize it. Serious disruption of a behavioural module may have unpredictable effects that interfere with the overall functioning of the individual e.g the impact of Parkinson's disease.

How good is this theory if we judge it against Ruse's epistemic and non-epistemic values. I am not convinced that our theory is fertile or falsifiable in its present form. But this may be a good thing because we can address these issues in the seminar.

The theory of evolutionary psychobiology is clearly fundamentally different to the SSSM (standard social science model) and it also differs from Cosmides and Tooby's evolutionary psychology. Here is a 'straw man' comparison of evolutionary psychology and evolutionary psychobiology to get the debate started.

Consider each area of interest/ type of evidence. If you can find examples / omissions / counterexamples to contradict my prejudices, bring them along to the seminar.

Area of interest / type of evidence Evolutionary psychology Evolutionary psychobiology
cognition principle focus of research 'one amongst many' rather than 'first amongst equals'
motivation secondary interest considered on an equal footing with cognition and emotion
emotion secondary interest considered on an equal footing with cognition and motivation
animal models not utilized very important as evolutionary psychobiology does not distinguish between humans and other animals
computer models of the brain utilized not utilized at present but may prove useful
modularity cognitive behaviours are modular all behaviours are modular.
role of neurochemical systems not considered major importance:
  • neurochemistry & neuroanatomy of reward
  • neurochemistry & neuroendocrinology of fear/anxiety , depression, aggression
role of ontogeny not considered very important, maturation and maturational experiences contribute to the development of behavioural modules and promote individual differences between animals
sex differences important important
individual differences not considered (? to avoid controversy over e.g. IQ?) important, they provide a window onto the influence of genetic, environmental and random factors on the continuous development of behavioural modules.
human 'universals' important important; their variability is acknowledged
random factors not considered very important, random factors contribute to the development of behavioural modules and thus individual differences between animals
Environment of Evolutionary Adaptation (EEA) important acknowledges that behaviour evolved in an environment, but the environment extends much further back in time than the point at which humans emerged.

 


Glossary



References and online resources


Supplementary reading

Copyright Dr. C.A.P. Kenyon 1994-2006