The Evolution of Mind and Society

Dr Andy WellsISP Flagship Lecture Series16th November 2010

Universal Declaration of Human Rights Article 1. All human beings are born free and

equal in dignity and rights.They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.

Conflict and co-operation Conflict and co-operation are the two most

fundamental concepts in human social psychology.

To begin to understand human social relations and social institutions we need to consider how and why the capacities for conflict and co-operation are deeply embedded in the human psyche.

That consideration is best undertaken from the standpoint of evolutionary theory.

Human sociality is part of our evolved biological heritage, extended and amplified by culture.

Human behaviour. Consider the following scenario:

John and Tom meet in the street and get into an argument. Tom pulls out a knife and stabs John who subsequently dies of his injuries. Tom is arrested and charged with murder.

Here’s another scenario: Jane and Teresa meet in the street and get

into an argument. Teresa pulls out a knife and stabs Jane who subsequently dies of her injuries. Teresa is arrested and charged with murder.

Sex Differences. Sex differences in physique, behaviour

and achievements of many kinds are normal rather than exceptional.

The data are not in question. Explanations are contested. Evolutionary explanations are an essential

part of a proper understanding of sex differences and of a broad range of other socially significant phenomena.

Estimated UK population age distribution 1999

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Nobel Prize Winners 813 individuals have been awarded a

Nobel Prize. 773 of them were men. The Nobel Prize has been awarded to 40

women since 1901. One woman, Marie Curie, has been awarded the Nobel Prize twice, in 1903 (Physics) and in 1911 (Chemistry).

40/813 = 0.049 In 2009 the prize for economics was

awarded to a woman for the first time.

Evolutionary explanation. Evolutionary theory explains species typical

behaviours and sex differences in behaviour. Evolutionary analysis grounds and illuminates

other types of explanation. Evolutionary theory provides powerful analytical

tools for social psychologists with many different interests.

The capacities for conflict and co-operation, modulated by systematic sex differences in behaviour, form the macro-structure within which the micro-structures of individual and group social relations can best be understood.

Human evolution: the big picture. Humans are the product of a lengthy

process of evolution. Like every other species on the planet we

are descended from single celled animals that existed billions of years ago.

We belong to the class of mammals. As such we are relative newcomers.

                                                              

               FIGURE 4 The evolution and classification of primates. Tarsiers are generally considered to be prosimians, but they are related more closely to anthropoids, so they

are recognized as haplorhine primates. Despite the ancient split of prosimian and anthropoid primates, they share many brain features that are unique to primates. Tree shrews, bats, and flying lemurs are thought to be close relatives of primates, forming the superorder Archonta, but the composition of Archonta is in doubt. mya,

millions of years ago. Based largely on Kay et al. (1997) and Purvis (1995).

The last ones standing… Humans supplanted the Neanderthals, either by

killing them or by displacing them into marginal habitats where they were unable to survive.

We have also caused the extinction of most of the large, land animals which existed when we came on the scene.

This has happened because Homo sapiens is a relatively large and powerful species with highly developed predatory instincts and exceptionally flexible social organisation.

Darwin’s two theories. Our current understanding of evolutionary

processes rests on two fundamental theories originally developed by Charles Darwin. The theory of natural selection. The theory of sexual selection.

Both theories are needed to explain human evolution and contemporary social behaviour.

Natural Selection 1.

Life is a competitive, often bitter, struggle to survive and to leave offspring.

Individuals differ in their characteristics. Some of these differences contribute to

success in the struggle. Differences can be mental as well as physical. Genetic uniqueness implies that social

behaviour is shaped primarily for individual interests and secondarily for group interests.

Natural selection 2. The (heritable) characteristics of successful

individuals spread through a population via their descendants.

The characteristics of unsuccessful individuals are lost.

Evolution has shaped humans physically and mentally for conflict and co-operation.

Inequality of opportunities and outcomes is a feature of the evolutionary process which has left its mark on the contemporary world.

Inequality All living humans are the descendents of

successful competitors in the struggle for resources.

In the contemporary world access to resources is grossly unequal.

Most of us, for most of the time, find it easy to live with fundamental inequality.

Indifference to absolute inequality is a signature of the evolutionary process.

Inequality relative to social reference groups is much more important for most people.

Inequalities of wealth and income. Pogge (2010) cites data which show that

the poorer 50% of the global population have 1.1% of global private wealth and 3% of global household income.

By comparison, the richest 10% have 85.1% of global private wealth and 71.1% of global household income.

Inequalities exist both between and within countries.

Social and societal psychologists should be aware of these huge disparities.

Sexual selection 1. Many creatures have characteristics that

imperil their survival. The enormous tail of the peacock is a classic example.

The theory of sexual selection explains how these characteristics can undergo positive selection if their mating benefits outweigh their survival costs.

Sexual selection involves both competition and choice.

Sexual selection 2. Darwin observed that competition for

mates typically occurs more strongly among males than among females and that females are typically more choosy than males about their choice of mate.

Darwin was unable to find a satisfactory explanation for this pattern.

Robert Trivers explained competitiveness and female choosiness in terms of differential parental investment.

Reproductive success. The currency of evolution is reproductive

success. Each of us is the product of an unbroken

chain of ancestors. Conflict, co-operation and systematic sex

differences are explained by understanding their links to reproduction.

None of this implies that our ancestors understood evolution or were immediately motivated by the desire for children.

It takes two to tango. Differential parental investment is one of

the key foundations of social relations. In sexually reproducing species the

female sex is defined as the one with larger gametes.

Anisogamy is the rule rather than the exception.

Differential investment. Human females invest much more heavily

than males in the early stages of parenting.

Because of this, access to females is the limiting factor on male reproductive success.

As a consequence males compete among themselves for access to females and for status and resources.

Sexual dimorphism. Dimorphism is an indication of a history of sexual

competitiveness. Humans are modestly dimorphic. Human males, on average, are taller, heavier

and more muscular than females indicating a greater degree of intra-sexual competition.

Sexual dimorphism underpins some notable behavioural differences between men and women such as the propensity for violence.

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Variance in reproductive success. Every human child has two parents, therefore,

on average, human females and males have equal numbers of children.

However, there is greater variance in reproductive success among males than among females.

This promotes more intense intra-sexual competition among males and strategies to promote exclusive access to females.

Males are also more interested, on average, than females in extra-pair copulations.

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Social relations pre-agriculture. Prior to the development of agriculture,

humans lived in small, nomadic bands. Competition was limited by scarcity of

resources and storage capacity. Co-operation was promoted by multiple

needs for social cohesion. Privacy was virtually non-existent. Individuals’ lives were open to public

scrutiny.

Social relations post-agriculture. Agriculture made settled living possible and

offered new arenas for competition and dominance.

Institutionalised social strata arose for the first time.

Armies became possible. Technological change was accelerated by a

social class freed from the constraints of daily food production.

Conflict became amplified by weapons technology and the raised stakes of the game.

Contemporary social relations. Contemporary social relations result from

interactions between individuals whose psychology has been shaped by multiple influences: The mammalian heritage. The primate heritage. The hominid heritage. Species specificity of Homo sapiens. Agriculture and writing. Contemporary environments.

Knowledge of evolution. Evolution is an inescapable force in human affairs. An understanding of the evolutionary processes that have

shaped human psychology leads to two related insights: Fundamental aspects of human social behaviour have deep

phylogenetic roots and are hard to change. Evolved human dispositions can be managed through the

construction of appropriate social institutions. Social engineering via the construction of institutions such

as political parties, legislatures and education systems must be informed by knowledge of the deep history of our species as well as by more recent events.