Enter your search terms Web www.flyfishingdevon.co.uk Submit search form

The Roots of Evolutionary Psychology Evolution and Theories of Behaviour: From Darwin to Evolutionary Psychology Author Paul Kenyon Charles Darwin Konrad Lorenz Niko Tinbergen James Watson E.O. Wilson Visit the SALMON Bookshop for recommended books on this topic

If you look at a school of fish, field of corn or flock of birds, you may be struck by the similarity between members of the same species. One sparrow is pretty much like any other sparrow and a randomly selected individual could be used to illustrate a type or species. This is the way most people viewed plants and animals until Darwin drew attention to subtle individual differences within species. This is most apparent in a species we are very familiar with - humans - we can easily distinguish between thousands of people we meet over a lifetime.

But the same is true of other animals. Farmers recognize individual cows and sheep in their care, and ornithologists are able to distinguish between birds by variation in their plumage. This picture shows how. Notice that each individual cow has a unique set of markings. Once it is pointed out this is obvious, but what is its significance? Variation extends beyond surface characteristics. Variation can be found throughout animal biology and behaviour. Darwin realized that variation was like 'grit in an oyster' - it provides opportunity for development and change.

Darwin's theory of evolution by natural selection

Darwin's theory of evolution involving natural selection based on variation led to a gradual abandonment of Greek typological (types) thinking which viewed species as static and unchanging.

This lecture does not discuss evidence that evolution has occurred (e.g. the fossil record, domestication etc.), but if you are interested here is a video of a lecture given by Paul Taylor ("Fossils: Extinction and Evolution") who works in the Natural History Museum in London. It is agreed by scientists that species that now exist originate from very simple forms of life that existed millions of years ago. There is no scientific evidence to dispute this claim. Darwin successfully demonstrated that evolution has occurred, and he gave us important insights into how evolution occurs. According to Darwin: organisms show variation in almost every aspect of their biology and behaviour variation is inherited - it is passed down from parents to offspring inherited variation affects survival and reproduction this mechanism is called natural selection Here is a lecture by Richard Dawkins on natural selection.

When Darwin published "The Origin of Species by Means of Natural Selection" in 1859 it was generally believed that offspring represented a 'blending' or mixing of characteristics possessed by their parents. Natural selection would not support the evolution of beneficial variations if parental characteristics were mixed in this way because variation would be halved in every generation.

We now know from Mendel's work published in 1865 that heredity is particulate - parents pass on particles or packages of information ( genes) to their offspring. For example,  children inherit the eye color of a single parent. Children of a brown-eyed father and blue-eyed mother do not end up with an intermediate eye color. Darwin was not aware of Mendel's discoveries and he was troubled by how variation could be inherited.

Mutation is an important source of genetic variation. Half the genes in our body come from our mother, half from our father. Mutation is an error that arises when genetic information is copied during the formation of sperm and eggs. Thus mutations may pass into the next generation. If the variation produced by the mutation enables the bearer to be more successful at surviving and reproducing, it will tend to spread through the population in succeeding generations.

View this PBS (2001) video 'A Mutation Story' which "...tells the story of a genetic mutation affecting the population of West Africa. Although helpful in preventing malaria, this mutation can also lead to sickle cell anemia. Sickle cell specialist Dr. Ronald Nagel stresses the genetic diversity required for the survival of a species."

Role of sexual selection

Darwin was struck by the fact that some animals seem to have characteristics that pose a serious threat to their survival. For example peacocks have elaborate plumage that would appear to make them conspicuous to predators and seriously hamper their ability to take flight. In a second book (The Descent of Man and Selection in Relation to Sex) published in 1871 Darwin suggested that such traits have reproductive advantages. Females may be more likely to mate with such males. Thus two mechanisms were thought to contribute to evolution: natural selection and sexual selection

Impact of Darwin's theory on social and political life

Darwin's ideas were - and continue to be - controversial because they can be applied to humans as well as other animals.

This story is told of two victorian ladies in conversation. One says: 'Have you heard that Mr Darwin says we are all descended from an ape?' The other replies: 'Oh, my dear - that surely cannot be true! . . . But, if it should be true, let us pray that at least it will not become generally known!'

Social Darwinism was championed by the British philosopher Herbert Spencer who coined the phrase 'survival of the fittest' which implies that only the ruthless will survive.

Boakes (1984) gives this summary of his views:

".. progress in society was to be achieved by a 'genuine liberalism' which maximized individual liberty and minimized interference from the State; vaccination, and care for the infirm or insane, only served to promote the regression of the human race; economic and social differences between races, sexes or classes were part of the natural order, a necessary part of evolution."

The British prime minister Margaret Thatcher seems to echo this philosophy when she declared that 'there is no such thing as society'

Spencer's views were particularly popular in America after the Civil War where industrialists interpreted fitness as the generation of wealth, and military campaigns against Sioux and Comanche Indians could be justified in terms of the survival of one group of people at the expense of another.

Boakes (1984) uses the term 'Psychological Darwinism' to describe the belief that there are significant psychological differences between groups of people due to differences in brain structure (neophrenology). Around the early years of the 20th Century British, German and American scientists who held similar views on the existence of racial types cited studies that measured human head shape and sizes as a way of differentiating between human races. These studies were conducted against a background of increasing opposition to immigration in the United states of America.

	This 1891 cartoon expresses the views of those opposed to immigration into the USA. The frock-coated politician is telling Uncle Sam that "If immigration was properly restricted you would no longer be troubled with anarchy, socialism, the Mafia, and such kindred evils!'" Captions on immigrants in the picture label them :Polish vagabond, Italian brigand, English convict, Russian anarchist, Irish pauper. Here is a larger version of this cartoon
Students of racial types used the Cephalic Index in which the breadth of the head above the ears is expressed in percentage of its length from forehead to back. Assuming that this length is 100, the width is expressed as a fraction of it. These photographs show three types of head from France. The cartoon contrasts the head shape of Florence Nightingale with a stereotyped (Irish?) immigrant Bridget McBruiser.   As head becomes proportionately broader, more fully rounded, cephalic index increases. Narrow heads were favoured for immigration purposes. This map of the Cephalic Index in eastern Europe shows narrow heads in Sweden, near Baltic, and broader heads in Bosnia, Serbia and White Russia.	Here is a larger version of this picture	Here is a larger version of this drawing
Map created by Madison Grant, Chairman, New York Zoological Society; Trustee, American Museum of Natural History, "The Passing of the Great Race, or The Racial Basis of European History," 1918, p. 220 ff.	This racial map shows: Nordics in pink, Alpines in green, Mediterranean's in yellow; and has crosses for Cro-Magnon area in Southwestern France. Here is a larger version of the map

But this view of race and the call to curtail immigration was abandoned in America in the 1920's after the anthropologist Boas showed that racial differences were not stable: Children born to immigrant mothers did not display the racial characteristics of their parents. This is the beginning of the idea that as environmental conditions improve, differences between people become minimal. Although young anthropologists and sociologists were persuaded by Boas' findings to abandon notions of inherited racial differences, older psychologists, particularly those in senior academic positions, were more reluctant.

At this time psychology was a a new subject struggling for recognition as a respectable scientific discipline. Psychological Darwinists played a prominent role in utilizing intelligence tests to aid recruitment to the American army which was engaged in fighting the First World War in Europe. This was obviously prestigious work for an emerging discipline which could have made a major contributions to the nation's welfare.

Things came to a head in the 1920's when some American psychologists (who were mostly WASPs - White Anglo Saxon Protestants) attempted to use the results of IQ tests to influence congress which was debating the introduction of legislation to restrict immigration from southern and eastern Europe. This attempt to use psychology to influence legislation was opposed by scientists who had suffered from racial discrimination on account of their 'non-Aryan' background. But the influence of Psychological Darwinism and eugenics persisted - and had horrific consequences - in Europe

Eugenics has its roots in the work of Darwin's cousin, Francis Galton who, in 1869, suggested that society should encourage breeding among its 'talented members' and discourage it in 'imbeciles' and 'idiots'. Darwin was convinced by his argument writing "You have made a convert of an opponent .... I have always maintained that, excepting fools, men did not differ much in intellect, only in zeal and hard work ..."

A trivial consequence of eugenics was the introduction of the first name Eugene. More seriously, in the USA some States had legislation to sterilize the 'feeble-minded'. Between 1907 and 1940, more than 35,000 involuntary sterilizations were carried out by the U.S. government on poor women, mostly in California (Platt 2002). In the words of one judge "three generations of imbeciles are enough" (Jones, 1993).

Similar views were expressed by the then British Home Secretary Winston Churchill who commented in 1910 that :

"The unnatural and increasingly rapid growth of the feeble-minded and insane classes, ..... constitutes a national and race danger which is impossible to exaggerate" (Jones, 1993)

In Germany the influential embryologist Ernst Haeckel laid the intellectual foundations for sterilization, genocide and antiabortion laws when he suggested that "The lower races are psychologically nearer to the animals than to civilized Europeans. We must, therefore, assign a totally different value to their lives."

Under the 1933 Law for the Prevention of Genetically Diseased Offspring, the Third Reich compulsorily sterilized about 400,000 victims, broadly categorized as "socially unfit by virtue of defective biology" (Platt 2002).

The title of Hitler's biography, Mein Kampf (My Struggle) echoes Spencer's phrase 'the struggle for existence' and he was clearly influenced by eugenic ides when he wrote that "Whoever is not bodily and spiritually healthy and worthy shall not have the right to pass on his suffering in the body of his children". But Hitler was not the sole architect of the horrors that descended on Europe between 1939 and '45. According to Jones (1993) "Half of those at the Wannesee Conference, which decided on the final solution of the Jewish problem, had doctorates, mainly in anthropology."

The eugenics movement in Nazi Germany believed it was possible to 'improve' the human gene pool and embarked on a program of genocide and sterilization and selective breeding - During WW2, there was the bizarre SS operation known as Lebensborn - a breeding program to produce 'racially pure' children. Although the popularity of eugenics waned in the USA in the 1920's, it persisted in Europe until the end of World War 2 when the full horrors of the concentration camps were exposed in newsreels across the world. But as late as 1988 the phrase "Idiots give birth to idiots" was used to justify restrictive marriage laws in China.

Although eugenics focussed on measuring physical attributes such as the size and shape of the head, it is clear that the racial characteristics targeted by eugenicists are behavioural, rather than purely physical. For example, the cartoon illustrating American objections to immigrants highlights behavioural (Polish vagabond, Italian brigand, English convict, Russian anarchist, Irish pauper), rather than physical characteristics.

Founding fathers of ethology and behaviourism

Konrad Lorenz Niko Tinbergen In 1972 Lorenz and Tinbergen received the Nobel Prize for their work.

After the second world war there were two broad approaches to the study of animal behaviour in Europe and America. The European school was founded in the 1930's by the Austrian Konrad Lorenz . He collaborated with the Dutch zoologist Niko Tinbergen to establish 'ethology' which he defined as the 'biological study of behaviour'. Tinbergen's book 'The Study of Instinct' remains the best introduction to the ethological approach to the study of animal behaviour. The American approach to animal behaviour has its roots in the work of J.B. Watson who in 1924 laid the foundation for an experimental approach to the study of behaviour in his book 'Behaviourism'. Watson was influenced by Pavlov's work on classical conditioning, and the English philosopher John Locke who believed that we are born as a blank slate "tabula rasa" on to which we write the associations we perceive in our environment. Watson's ideas were adopted by experimental psychologists who were particularly interested in studying learning under laboratory conditions. Perhaps the best known exponent of this approach in its purest form was Fred Skinner who believed that behaviour was shaped by reward. Essentially reward leads to the repetition of a behaviour.

Fred Skinner The rat's behaviour is 'shaped' by giving a pellet of food delivered via a button in Skinner's hand.

Characteristics of ethology and comparative psychology

Ethologists are concerned with: identifying and describing species-specific behaviours. These are behaviours that show little variability between members of the same species e.g. courtship displays in birds understanding the evolutionary pathway through which the genetic basis for the behaviour came about. Many ethologists capture their observations on videotape or audio tape. From their observations they make an ethogram: a description and documentation of the behavioural patterns under study, a behavioural inventory. The first ethologists were European scientists (e.g. Lorenz, Tinbergen) trained in zoology; studied the evolution of behaviour; in birds, fish and insects; used field experiments and made observations of animal behaviour under natural conditions; discovered species specific fixed action patterns elicited by sign stimuli acting through innate releasing mechanisms; used the term instinct to explain motivation

Behaviourists and comparative psychologists were: initially North American scientists, trained in psychology, rejected the notion of instinct interested in the flexibility of behaviour shown by individuals rather than the evolution of behaviour in species, and understanding the environmental requirements for the development of behaviour in the young; Studied how we learn new behaviours, using a restricted number of species, principally rats and pigeons, under laboratory conditions, using statistical methods and carefully controlled experimental variables, with the intention of discovering general laws of behaviour that could be applied to all species including humans.

Here is a summary of these very different approaches, interests and backgrounds:

Tension between ethology and psychology

It is perhaps not surprising that ethologists and behaviourists would eventually clash over their very different approaches to recording, analysing and interpreting behaviour. After all they were studying very different types of behaviour. For example, whilst ethologists were observing courtship displays in the field, psychologists were poring over cumulative records showing the impact of schedules of reinforcement on rates of bar-pressing in rats trained in Skinner boxes under carefully controlled laboratory conditions.

An extreme form of behaviourism - Radical Behaviourism held that:

• there was no such thing as a 'human nature'; we are born with the capacity to learn and all behaviour is the result of this capacity
• behaviour is a result of consequences (reinforcement) rather than 'instincts' that have been shaped by natural selection
• learning exhibits equipotentiality; learning occurs despite the responses, stimuli or reinforcers involved

One flash point between behaviourists and ethologists was interpretation of how behaviour develops.

According to Lorenz, species-specific behaviour develops without the animal experiencing the stimuli to which it responds, or without practice of the motor patterns that it performs.

Terms associated with this view that behaviour is the result of 'nature' include:

• instinctive behaviour
• innate behaviour
• inherited behaviour
• genetic bases of behaviour

The American John Watson is credited with emphasizing the role of nurture in development. His view that we are born as a blank slate "tabula rasa" is captured by his famous claim:

"give me a dozen healthy infants, well -formed, and my own specified world to bring them up in and I'll guarantee to take anyone at random and train them to become any type of specialist I might select - doctor, lawyer, artist, merchant-chief, and, yes, even beggar man and thief , regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors" (see Boakes, 1984, pp226).

Watson was trying to develop a psychology that could be utilized by "the educator, the physician, the jurist and the business man ... in a practical way"

Terms associated with the view that behaviour is the result of 'nurture' include:

• acquired behaviour
• learned behaviour

In his recent book "The Blank Slate: The Modern Denial of Human Nature", Steven Pinker (2002) points out the social impact of this type of thinking

"The Blank Slate has also served as a sacred scripture for political and ethical beliefs. According to the doctrine, any differences we see among races, ethnic groups, sexes, and individuals come not from differences in their innate constitution but from differences in their experiences. Change the experiences—by reforming parenting, education, the media, and social rewards— and you can change the person. Underachievement, poverty, and antisocial behavior can be ameliorated; indeed, it is irresponsible not to do so. "

Nowadays most psychologists accept that behaviour develops as an interaction between factors in an animal's environment, as well as biological predispositions. It is worthwhile examining some of the evidence that laid the foundation for this synthesis.

Maturation and practice of pecking by chicks
The development of pecking in newly hatched chicks is an example of the interaction between maturation (nature) and practice (nurture) in the development of a behaviour. Newly hatched chicks have an inherited tendency to peck at objects which contrast with their background, at first their aim is poor but it does improve. Cruze studied how this improvement occurs. He measured pecking accuracy by testing chicks individually in a small arena with a black floor onto which he scattered several grains of millet. Each chick was allowed 25 pecks; each peck was scored as a hit or miss.

Experimental design:

The experiment involved nine independent groups of chicks:

• Tested after being kept in dark for 24 hours with no opportunity to practice
• Tested after being kept in dark for 48 hours with no opportunity to practice
• Kept in dark for 36 hours, given 12 hours in light to practice pecking, then tested when 48 hours old
• Tested after being kept in dark for 72 hours with no opportunity to practice
• Kept in dark for 60 hours, given 12 hours in light to practice pecking, then tested when 72 hours old
• Tested after being kept in dark for 96 hours with no opportunity to practice
• Kept in dark for 84 hours, given 12 hours in light to practice pecking, then tested when 96 hours old
• Tested after being kept in dark for 120 hours with no opportunity to practice
• Kept in dark for 108 hours, given 12 hours in light to practice pecking, then tested when 120 hours old
• (Chicks were hand fed whilst in the dark)

Results:

• As the chicks mature (age) there is a steady improvement in accuracy even though they have not had any opportunity to practice pecking.
• At any age, 12 hours of practice greatly improves accuracy.

Conclusion: pecking improves as a consequence of both maturation and practice.

Limits to behaviourism: Preparedness and taste aversion learning

Behaviourists such as Skinner gave the impression that it was possible to condition any response that an animal could perform. However, the idea that through the process of operant conditioning, any reinforcer should be equally effective in increasing the frequency of any response was soon in serious doubt.

For example, although it is fairly easy to train a rat to run in a wheel to avoid shock, it proved impossible to condition a rat to rear (stand upright) to avoid the aversive stimulus. Seligman argued that evolution had prepared animals to make certain associations more easily than others. Thus rats are 'prepared' to run, but not to stand on their back legs, to avoid or escape from an unpleasant stimulus (data redrawn from Bolles, 1973)

In a famous experiment Harlow raised infant rhesus monkeys in isolation from their mother. They were provided with two 'surrogate mothers'

• a bare, hard, wire monkey that provided no warmth or softness, but contained a bottle of food
• a soft terrycloth-covered wire monkey, but it had no food bottle

Harlow found that the infants spent most of their time clinging to the soft terrycloth-covered monkey even though it was not the source of food reinforcement.

Garcia and Koelling (1966) carried out an experiment on taste aversion learning involving 'bright noisy water' and illness induced by exposure to X-radiation. The training and testing conditions in their experiment are described in this table.

Training conditions		Testing conditions	Consequences	Association learned?
Rats trained to drink water from a spout that caused a flash of light and a click when the rat's tongue touched to spout - 'bright noisy water'	Made sick by X-radiation after drinking	Offered 'bright noisy water'	Drink normally
	Given electric shock after drinking	Offered 'bright noisy water'	Fail to drink
Rats trained to drink water sweetened with saccharine	Made sick by X-radiation after drinking	Offered water sweetened with saccharine	Fail to drink
	Given electric shock after drinking	Offered water sweetened with saccharine	Drink normally

The results show that rats did form an association between

• external cues ('bright noisy water') and shock
• a distinctive taste (saccharin) and illness

But, rats did not form an association between

• external cues ('bright noisy water') and illness
• a distinctive taste (saccharin) and shock

According to traditional behaviourists, all the groups of rats should have learned an association between drinking from the spout and the aversive consequences, and should not have drunk under the test conditions. Therefore, Garcia's results challenge the idea that any reinforcer is equally effective in increasing the frequency of any response

Problems with viewing behaviour as either nature or nurture

The Birth of Sociobiology and Evolutionary Psychology

Cosmides and Tooby describe several principles that guide an evolutionary psychology approach to any topic within psychology:

1. Modern skulls house a stone age mind." This is a catchy way of conveying the idea that human evolution occurred in a very different environment to the one in which we now live. Humans evolution is thought to have started 6-8 million years when we diverged from our primate ancestors. Evolutionary psychologists believe that natural selection designed our minds for life in an environment resembling the African savannah , in which our hunter-gatherer ancestors lived for thousands of years. For 99% of our evolutionary history we probably lived in hunter-gatherer societies. It is only about 10,000 years since humans first started growing their own food. The technical term used to refer to the environment in which we evolved is the Environment of Evolutionary Adaptedness EEA) . The EEA does not refer to some short period of time in our past. It refers to an array of factors that have influenced inclusive fitness during our evolution over the last 200,000 years. See Daly & Wilson (1999) for a very good discussion of this important distinction.
   The EEA may have involved (Badcock, 2000):
   food obtained via hunting / gathering /scavenging
   • nomadic or semi-nomadic existence
   • low population density
   • small kin-based groups
   • high infant mortality
   • low life expectancy
   • vulnerability to predators and disease

     Boaz and Almquist (1999) provide a detailed account of human evolution.

     

   ---

2. The human brain consists of neural circuits designed by natural selection to solve problems that our ancestors faced during our evolutionary history. Our mind consists of a collection of adaptations. Each individual adaptation has evolved to meet challenges in the environment, challenges faced in our EEA.

   ---

3. Most of what goes on in the mind is unconscious . Most problems that we think are easy to solve are in fact very difficult to solve and require complicated neural circuitry. Consider vision, vision appears easy - open your eyes and you see the world - but this apparent simplicity hides a complex evolved system that we have not been able to reproduce artificially.

   ---

4. Different neural circuits are specialized for solving different adaptive problems. An adaptation is
   

   "a characteristic that has arisen through and been shaped by natural and or sexual selection. It regularly develops in members of the same species because it helped to solve problems of survival and reproduction in the evolutionary ancestry of the organism. Consequently it can be expected to have a genetic basis ensuring that the adaptation is passed through the generations." (Williams, 1966)

   
   Evolutionary psychology views the mind as consisting of specialized modules that have evolved with the purpose of coping with adaptive problems. In contrast, psychologists have tended to view the mind as consisting of general purpose circuits involved in many different behaviours e.g. learning, intelligence, memory, reasoning, decision-making. You can see this approach reflected in the way your degree programme is broken down into modules covering these topics.

   ---

The overarching concern of evolutionary psychology is to identify factors that maximize reproductive success .

Evolutionary psychologists are particularly interested in psychological mechanisms that:

• are universal i.e. do not vary greatly between individuals
• are closely related to reproductive success : e.g.
  • attracting a mate
  • choosing a mate
  • raising offspring
  • kin recognition
  • maintaining relationships
  • acquiring status
  • cheater-detection
  • maintaining group cohesion

Eibl-Eibesfeldt took these pictures of a Himba woman from Namibia (SW-Africa). She shows a rapid brow raising (between the second and third still images) which coincides with raising her eyelids. Because all the cultures he examined showed this behaviour, Eibl-Eibesfeldt concluded that it was a human 'universal' or Fixed Action Pattern. How do you think this behaviour is related to reproductive success?

The debate between the Standard Social Science Model (SSSM) and Evolutionary Psychology (EP)

According to some evolutionary psychologists (e.g. Cosmides and Tooby) the Standard Social Science Model (SSSM) is the prevailing orthodoxy in anthropology, sociology, and has dominated psychology since the 1920's.The SSSM is under challenge from Evolutionary Psychology (EP) which has mounted a critique of contemporary psychology because it has largely ignored the role of evolution in shaping human behaviour.

Problems for Evolutionary Psychology (EP)

Some behaviours do not appear to be adaptive:

• homosexuality
• schizophrenia
• obesity caused by excessive intake of fats and sugars

EP has been criticized for its methodology which is very similar to that used by Darwin. Darwin argued that no single experiment or observation would prove natural selection. He gathered a wide variety of different types of evidence and argued that they could all be explained by natural selection. In other words various pieces of evidence converged to support natural selection.

A similar approach is used by EP which relies on data from the following sources (see Buss (1999):

• archaeology
• data from hunter-gatherer societies
• systematic observation of human behaviour
• self-reports
• public records e.g. marriages, divorces, wills
• human artefacts e.g. plays, music, magazines, newspapers, TV programmes

Just like Darwin they argue that data from these multiple sources converge to support the concepts developed by evolutionary psychology

Get-outs for Evolutionary Psychology

• interaction with a particular environmental feature during development may be critical for the normal development of an adaptation. Schizophrenia and autism may the consequence of a missing or abnormal environmental feature during development.
• interaction with a particular environmental feature may be critical for the normal expression of an adaptation in adulthood. For example in their important work on homicide, Daly and Wilson argued that infanticide by stepparents is not an adaptation, but instead it is a failure of normal parental care which is elicited by offspring.
• every feature does not require an adaptive explanation. Features may be by-products of an adaptive feature e.g. the belly button is a by-product of an adaptive feature - the placenta.
• modern obesity caused by preference for calorie-rich foods which was adaptive in the EEA

Evolutionary psychology is not ...

• ... a basis for formulating one's personal approach to moral and ethical issues thrown up by everyday life. Avoid adopting scientific theories as a basis for your beliefs about how you behave towards other people. Scientific theories are simply a way of organizing findings about the world, and suggesting ways of finding more about the world. What you do with this knowledge in your everyday life is a very personal matter. Remember that theories, particularly theories about human behaviour, have the habit of being disproved; this can leave you high and dry if you depend to much on them in everyday dealings with people. After all the very essence of a theory is to invite contradictory evidence. Caporael (2001) commented:

  "..... everyday life makes sense when viewed through an evolutionary lens. However, it can be just as well argued that selfish gene theory was created in the image of common beliefs about everyday life ...."

  This lecture gives several examples where the misapplication/misunderstanding of theory has resulted in tragic consequences for millions of people. If this lecture has taught you nothing else your time spent reflecting on this point will have been well spent.

• ...saying that all adaptive behaviour is present at birth. Teeth and breasts have evolved and are not present at birth, but nobody would argue that people learn to have these features. These features appear as a result of maturation at a time when the provide adaptive advantage. The same argument holds for the development of behaviours.
• ...is not saying that behaviour is genetically determined. The idea that behaviour is caused by genes without environmental influence is simply false. The environment plays a crucial role in influencing how we develop and react. For example, I develop sunburn if I expose my skin to a sunny environment. If I don't want to burn I can simply avoid overexposure to bright sunlight.
• ...saying that behaviours evolve. Evolution works on genes, and combinations of genes. Genes code proteins, and proteins build the structure of the brain and body. Behaviour is the result of brain activity. Strictly speaking genes - rather than behaviour - form the raw material on which natural and sexual selection works.
• ...saying that adaptive behaviours are beyond our control. Knowing that a behaviour has evolved does not mean that we cannot take steps to deal with its undesirable side effects. For example, our lungs have evolved to support respiration but smokers can develop lung cancer. The solution is obvious - avoid cigarette smoke. This also shows how knowledge of genetic adaptations can help us lead healthier lives.
• ... a description of the way we should behave. Some of the behaviours studied by evolutionary psychologists are illegal or abhorrent. Evolutionary psychology seeks to explain these behaviours. It is not used to justify behaviour. The naturalistic fallacy refers to the confusion of 'is' with 'ought'. This is the trap that Social Darwinists fell into. Heart disease, volcanoes, and cancer are all natural phenomena. This does not mean that these things represent how the world ought to be. We have doctors, vulcanologists and research scientists to understand phenomena in order to seek solutions to the problems they cause. The same argument holds for evolutionary psychologists who may give us important insights into undesirable aspects of human behaviour.
• ...saying that we are perfectly adapted. In no way is our behaviour perfectly adapted. For example, we like high-calorie fatty sweet foods which lead to obesity. A better designed adaptation would allow us to monitor food intake in the light of body weight. One explanation for this paradox is evolutionary time lag: Our food preferences evolved in an environment where these types of food were rare and it was advantageous to consume them in large amounts when they were available.
• ...politically incorrect, racist, an attack on democracy. The idea that learning is the result of general purpose circuits suggests that 'anyone can be anything'. EP suggests that we all possess universal modules. We have the same biological endowment which places us all on an equal footing and does not challenge the idea that 'anyone can be anything'
• ..sexist. Evolutionary psychology has discovered several previously unappreciated differences between men and women. But it does not suggest that the behavioural adaptations of one gender are better than those of the other. Men and women differ in anatomical terms: men have testes, women ovaries, but to say that ovaries are better than testes or vice versa is meaningless. Evolutionary psychologists and endocrinologists study sex differences, they do not denigrate or distort them. It is meaningless to say that endocrinologists and evolutionary psychologists are sexist.
• ..saying that our genes control us so that we behave like programmed robots. Consequently we cannot justify our behaviour by arguing that "my genes made me do it". Evolutionary psychology does not pretend to be a moral code. Evolutionary theory explains why things are as they are. It does not follow that these things are 'right', 'natural, or 'good'. We are not forced to accept things as they are. We are free to make moral choices and utilize the knowledge provided by evolutionary psychology to modify our environment or behaviour in the quest for health and happiness.
• ... a substitute for religion. At least not explicitly: "..certain aspects of selfish gene theory share a conceptual deep structure with religion: Like the soul, the immortal genes are the essence of the individual, whereas the body, vessel of the soul or vehicle of the genes, is transitory and ephemeral.", Caporael (2001). The recent spat between Richard Dawkins and creationists about the teaching of evolution in UK schools might make you pause to reconsider Caporeal's suggestion.

Ways of thinking about behaviour

One way of thinking about behavioural questions is to consider how they relate to stages on a species' journey through time, from the distant past into the future.

The evolution question: How has a behaviour evolved in the species? Is it shown by closely related species? The development question: How does a behaviour develop during the individual's lifetime? Does the individual learn the behaviour? Does s(he) practice the behaviour? Is the behaviour performed perfectly the first time it is performed? The cause question: What causes the particular behaviour? Are there internal factors (e.g. hormones) that influence the behaviour? The function question: Why is the behaviour performed in a particular way? How do the behaviour contribute to the reproductive success of the individual, and ultimately the survival of the species?

Online resources

• Barash  (2002). Turning the Tables on the Tabula Rasa. Human Nature Review. 2: 444-448.
• Boeree (1988). Sociobiology. Published online at http://www.ship.edu/~cgboeree/sociobiology.html. An easy to read explanation of the major concepts of Sociobiology, including Ethology, Evolution, Attraction, Sexual Dimorphism, Imprinting, Kin Selection, Reciprocal Altruism, and Dominance Hierarchies. Contrasts the roles of Sociobiology and Culture.
• Brown (2002) The Darwin Wars: The Scientific Battle for the Soul of Man.Touchstone Books. Sections available online
• Campbell (2002). Book review of The Darwinian Revolution: Science Red in Tooth and Claw by Michael Ruse, Second edition. The University of Chicago Press, 1979, 1999. The Human Nature Review   Volume 2: 132-134 ( 5 April )
• Carruthers (2002) Is the mind a system of modules shaped by natural selection? In C. Hitchcock (ed.), Contemporary Debates in the Philosophy of Science. Oxford: Blackwell, 2003. (In draft.)
  • more Carruthers' articles on mental architecture
• Connor (2003) "James Watson Nobel Prize Winner. Welcome to the Watson Wonderland: DNA genius still ruffles feathers 50 years after extraordinary discovery". The Independent, Monday 3rd February, 2003 , p 11. available online
• Cosmides and Tooby Evolutionary Psychology: A Primer is available online at http://www.psych.ucsb.edu/research/cep/primer.html
• Daly and Wilson (1999). Human evolutionary psychology and animal behaviour, Animal Behaviour , 57, 509-519. This journal is available online for Plymouth students through the library.
• Darwin (1871). The Descent of Man and Selection in Relation to Sex. Available online
  • see also Wyhe (2003) "The writings of Charles Darwin on the web" which is described as "the only website which provides the digitized writings of Darwin in citable form with original page numbers and bibliographical details".
• Fodor (1998). The Trouble with Psychological Darwinism. London review of Books, Vol 20, No 2 | cover date 15 January 1998. Available online at http://www.lrb.co.uk/v20n02/fodo2002.html
• Griffiths (2002). Evolutionary Psychology: History and Current Status. To appear in Sarkar (Ed). The philosophy of Science: An Encyclopedia. New York: Routledge. Traces the roots of evolutionary psychology from classical ethology, sociobiology and cognitive science.
• Hayashi (1999). Pinker and the Brain.  Scientific American, July 1999 issue
• Kennair (2002). Evolutionary Psychology: An emerging integrative perspective within the science and practice of psychology. The Human Nature Review,  Volume 2: 17-61 ( 15 January )
• Kevles (2002) Book review of A Life of Sir Francis Galton: From African Exploration to the Birth of Eugenics. Nicholas Wright Gillham. Oxford University Press, 2001 available online at http://americanscientist.org/bookshelf/Leads02/kevles.html
• Thomas Malthus (1766-1834) brief online description of impact of Malthus on Darwin's thinking
• PBS (2001) video Darwin: Reluctant Rebel
• PBS (2001) video  Evolving Ideas: Who Was Charles Darwin?
• PBS audio interview with James Moore: Darwin and Victorian Culture
• PBS (2001) video Darwin and Malthus
• PBS (2001) video Evolution of the Eye
• PBS (2001) video A Mutation Story
• Pinker (2002) "The Blank Slate: The Modern Denial of Human Nature",  Viking Penguin.
• Pinker (2002) a video (authors@MIT 2002) in which Steven Pinker discusses his book "The Blank Slate: The Modern Denial of Human Nature".
• Pitchford and Young The Human Nature Review. A site with extensive coverage of  evolutionary psychology, well worth a visit. Available online at  http://human-nature.com/
• Sapolsky (2002).The Loveless Man ... who invented the science of love. Scientific American, November 2002. Sapolsky gives a revealing insight into Harlow's private and professional life in this review of Love at Goon Park: Harry Harlow and the Science of Affection by Deborah Blum Perseus Publishing, 2002
• Stewart (1995) The Importance of Being Flashy. International Wildlife. September/October 1995. Discusses why individuals with the most attention-getting displays tend to be the most successful.
• Stotz and Griffiths (2001) Dancing in the Dark: Evolutionary Psychology and the Argument from Design. To appear in Scher, S and M. Rauscher (Eds), Evolutionary Psychology: Alternative Approaches, Dordrecht, Kluwer, 2001.
• Wilson (1996) radio interview from Science Friday Archives November November 15, 1996. Be patient - the interview gets interesting after about 9 minutes.
• Wyhe (accessed 21/2/2003) "The writings of Charles Darwin on the web" described as "the only website which provides the digitized writings of Darwin in citable form with original page numbers and bibliographical details".
  

References:

• Alcock, (1998). Animal Behaviour: An Evolutionary Approach , Sinauer, Sunderland. Alcock presents a balanced, interesting, and clearly presented discussion on current thinking about the evolution of human behaviour in chapter 16 of this book.
• Badcock (2000). Evolutionary Psychology: A Critical Introduction. Polity Press.
• Boakes (1984). From Darwin to behaviourism. Cambridge University Press, Cambridge.
• Boaz and Almquist (1999). Essentials of Biological Anthropology, Prentice-Hall, New Jersey.
• Bolles (1973). The comparative psychology of learning: The selection association principle and some problems with "general" laws of learning. In Perspectives in Animal Behavior. Bermant (Ed). Scott, Foresman & Company, Glenville, IL.
• Brown (2002) The Darwin Wars: The Scientific Battle for the Soul of Man.Touchstone Books
• Buss (1999) Evolutionary Psychology. Allyn and Bacon, Needham Heights, MA.
• Caporael (2001). Evolutionary Psychology: Toward a Unifying Theory and a Hybrid Science. Annual Review of Psychology.
• Connor (2003) "James Watson Nobel Prize Winner. Welcome to the Watson Wonderland: DNA genius still ruffles feathers 50 years after extraordinary discovery". The Independent, Monday 3rd February, 2003 , p 11.
• Jones (1993). The Language of the Genes, Flamingo, London.
• von Hippel (2000). Acta Ethologica, 2,83-89.
• Williams (1966). Adaptations and Natural Selection. Princetown University Press.
• Wilson (1975). Sociobiology the New Synthesis, Cambridge, Mass..: Harvard University Press.