Mind, Brain and Behaviour

1
Mind, Brain and Behaviour

• Framing biological and evolutionary questions
  about human nature

2
The ghost in the machine
Modern views of the mind are based upon a
Cartesian world view (which saw a split between
the body and the mind/soul)

• The soul/reason is the animating principle
  without which the body would seem just a machine
• The rational principle was key to identity and
  to truth (I think, therefore I am)
• Later thinkers (e.g. de la Mettrie) omitted the
  idea of the soul and pursued a purely mechanistic
  vision of the world

3
Modern psychology

• Biological, cognitive and evolutionary psychology
  are mechanistic and reductionistic
• Mind is modular, physical and reducible to
  neurochemistry, specialist neural architecture
  and adaptive mechanisms
• Atomistic view suggests that the body/mind
  consists of smaller structures that can be
  studied in their own right
• Important implication of this view a
  reductionistic view characterises the best
  explanation of behaviour, i.e. there is no
  holistic, systemic conception of how the system
  works as a whole

4
Roots of modern biopsychology

• Location of mind heart or brain?
• Galen situated mind in the ventricles of the
  brain but the vital spirit which animated the
  body and brain was situated in the heart

5
Mechanism vs Vitalism

• Debates on the nature of perception Goethe vs
  Newton
• Debates on the nature of the mind Fodor vs
  Edelman
• Debates on the nature of the body and disease
  holistic vs conventional medicine

6
Assumptions of Biopsychology

• Assumes that even quite complex human behaviour
  and thought can be explained according to
  physiological mechanisms, e.g. hormones,
  neurotransmitters
• Genes (and gene-environment interactions) often
  assumed as ultimate causes of behaviour that help
  structure physiology and hence behaviour
• Research focuses on detecting ever-finer levels
  of physiological functioning in order to discover
  the causes of behaviour

7
Natural Selection
Organisms struggle for limited resources
Individuals vary in their physical behavioural
characteristics
NS shapes the characteristics of organisms and
those that survive are better adapted to the
environment
Some characteristics give organisms an advantage
over other organisms and thus enable them to
leave more offspring
8
Evolutionary psychology rationale

• Stresses continuity of behaviour between humans
  and animals
• Claims that evolutionary explanations should be
  sought for wide range of behaviour
• Seeks to unify psychological approaches and
  close the gap between psychology and the natural
  sciences

9
Universal human nature
Gradually shaped by NS over time
Help shape culture
Evolved psychological mechanisms
Mental mechanisms seen as domain-specific modules
to solve specific problems (e.g. finding food,
mates)
Adapted to problems found in EEA
Adaptations
10
Evolved psychological mechanisms

• Evolutionary psychology sees the mind as a bit
  like a Swiss army knife consisting of
  domain-specific modules (sets of algorithms or
  rules) evolved to solve specific problems our
  ancestors faced, e.g. spatial cognition, mate
  selection, parenting. This is essentially a
  mechanistic view of the mind as an
  information-processor.
• Investigators might infer psychological
  mechanisms from knowledge about ancestral
  adaptive problems, or use evidence of existing
  psychological mechanisms to infer details of
  ancestral conditions and problems in the EEA.

11
Environment of Evolutionary Adaptation (EEA)
Modern history and culture, including
agriculture, only dates back to the last few
thousand years.
Yet the earliest human species dates back 2.5
million yrs. Thus the time since the beginnings
of agriculture (10,000 yrs ago) is less than 1
of the 2 million yrs our ancestors spent as
hunter-gatherers in the Pleistocene. The EEA
therefore shapes our modern psychology and
behaviour.
12
Levels of selection
Basic unit of selection is the gene, bodies are
simply vehicles for genes NS acts on
individuals, since it is individuals who live or
die NS acts on groups on a long term view it is
groups that survive or die out
GENE
INDIVIDUAL
GENE
GROUP
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Neodarwinism The modern synthesis

• Theory of Natural Sexual Selection Mendelian
• genetics
• Later researchers added the concepts of inclusive
• fitness and kin selection (Hamilton, 1964)
• Central dogma information flows from the
  genotype to the phenotype, and not the other way
  around as suggested by Lamarck
• Indicates a physical and reductionistic view of
  life

14
Tinbergens Four Causes

• How does the behaviour develop (ontogeny or
  development)?
• How did the behaviour evolve (evolution)?
• What mechanism caused the behaviour (causation)?
• What is the behaviours function (survival
  value)?
• Psychologists have tended to focus on the first
  two of these causes. Evolutionary psychologists
  focus on the last two.

15
Why do birds sing?

• What physical features of the vocal cords and
  beak enable sound to be produced?
• Is the ability to sing innate or does a bird
  have to learn the song of its species?
• How has the variety of bird song we hear today
  evolved over evolutionary time?
• What is the survival value of bird song?

specific to general
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Criticisms of evolutionary psychology

• All behaviours are not adaptive
• Researchers disagree as to the nature of EEA
• Finding adaptive explanations for behaviour
  leads to Just- so stories
• Researchers infer causes from results
• Gradual view of evolutionary change has been
  criticised
• The role of culture is given little importance

17
The charge of Panglossianism

• Evolutionary psychology attempts to find an
  adaptive reason behind every physical, mental and
  behavioural characteristic. Even though some
  behaviours are not adaptive, it is assumed that
  they were at one time (in our evolutionary past).
• For example, Wright (1994) suggests that our
  fondness for sugar, while not particularly
  healthy today in our fast-food, carbohydrate-rich
  culture, presumably evolved in an ancestral
  environment where fruit was relatively scarce and
  a good source of vitamins (cited in Gould, 2000).
• Gould calls this pure guesswork and suggests
  that most such examples constitute Just-so
  stories.

18
Telling Just-So Stories
Some critics (namely Gould Lewontin, 1979)
accuse evolutionary psychological accounts of
being little more than contrived stories
speculating how behaviours and psychological
characteristics may have evolved (after Kiplings
humorous accounts).
Problem is one of inferring causes from results.
However, EP is not necessarily unscientific
because predictions can be made about EEA
conditions based on existing psychological
behaviours and mechanisms (and vice versa).
19
Understanding the EEA

• The problem is that we cannot know for sure what
  our hunter-gatherer ancestors lived like 2
  million years ago.
• Fossil record is fragmentary and there is little
  evidence of the details of their social or
  psychological life.
• In addition, the EEA was not just one period
  sometime in the Palaeolithic, but is best
  conceptualised as a number of different periods
  in historical time. We know little about how
  different psychological characteristics of our
  ancestors were developed to fit these different
  environments.

20
The role of culture

• EP stresses universality of human nature, e.g.
  race does not determine intelligence. However,
  the role of many cultural aspects in shaping many
  aspects of modern life is ignored, while other
  features of culture are seen as universal.
• In particular, emphasis is placed upon inherited
  gender specific behavioural responses, for
  example abuse by stepfathers. All behaviours are
  seen as adaptive
• From pregnancy complications, to the stress
  response, to the beauty in symmetry, to the
  attraction of money, to the historical tendency
  of the rich to favor firstborn sons, everything
  we think, feel and do might be better understood
  as a means to the spread of our own - or our
  ancestors - genes.
• Betzig (1997) cited in Rose (2000).

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Summary key concepts

• EP approach assumes people show physical and
  mental adaptations to ancestral environments
  (EEAs). These adaptations, shaped by NS, can be
  assumed to be universal.
• Evolved psychological mechanisms, shaped during
  EEA, can explain complex human behaviour (from
  altruism to religion). These mechanisms/modules
  originally helped our ancestors to solve specific
  adaptive problems.
• Critics of EP challenge its assumptions about
  adaptation, the EEA and the universality of human
  nature.

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References

• Barkow, J. H., Tooby, J. Cosmides, L. (1992).
  The Adapted Mind Evolutionary Psychology and the
  Generation of Culture. Oxford Oxford University
  Press (especially chapter The Psychological
  Foundation of Culture by T C.
• Barrett, L., Dunbar, R. Lycett, J. (2002).
  Human Evolutionary Psychology. Palgrave.
• Orians, G.H. Heerwagon, J.H. (1992). Evolved
  responses to landscapes. In The Adapted Mind.
• Lewontin, R.C., Rose, S. Kamin, L. (1984). Not
  in our Genes. New York Pantheon.
• Rose, H. Rose, S. (2000). Alas, Poor Darwin
  Arguments against Evolutionary Psychology.
  London Jonathan Cape. See especially chapters
  by H. Rose and S. J. Gould.
• Gould, S.J. Lewontin, R.C. (1979). The
  Spandrels of San Marco and the Panglossian
  Paradigm A critique of the adaptationist
  programme. Proceedings of the Royal Society of
  London, 250, 281-288.