Introduction to Psychobiology

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Introduction to Psychobiology

• Mind, Brain and Behaviour
• NoH 2006

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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

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Evolutionary Psychology
EVOLUTIONARY PSYCHOLOGY Evolutionary basis of
behaviour and culture Humans are animals and have
been subjected to the same processes of
evolutionary change as all other living things on
earth (e.g. John Tooby, Leda Cosmides, David
Buss, Martin Daly, Margo Wilson, Donald Symons,
Laura Betzig, Steven Pinker
SOCIOBIOLOGY Evolutionary explanations of social
behaviour (e.g. Wilson, 1975)
Criticises the SSSM (Standard Social Science
Model) as being cut off from the natural
sciences We are products of biology and culture,
nature and nurture
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Which statement is correct?

• Evolution is progress from lower to higher life
  forms

b. Evolution is not about progress, but about
random change
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http//www.pbs.org/wgbh/nova/link/evolution.html
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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
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Key words to evolution

• V Variation
• I Inheritance
• S Selection
• A Adaptation

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Variation

• All individuals within a species show variation
  in their behaviour, morphology or physiology
• This variation is called the PHENOTYPE
• The basis for this variation lies in the genes of
  the individual. The genetic variation is called
  the GENOTYPE
• Genotype Environment Phenotype

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Genotype (Facultative genes)
Environment (diet, nutrition, toxins etc)
Phenotype (tall, medium, small etc)
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Sickle Cell anemia

• http//www.pbs.org/wgbh/evolution/library/01/2/l_0
  12_02.html
• 5 mins..
• Examples of other cases of recent evolution-
  Lactose intolerance

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Selection and Adaptations

• Traits that are favourable help organisms to
  survive and reproduce
• Thus, favourable traits are passed on to the next
  generation.
• The favourable traits are called ADAPTATIONS
• Psychological adaptations difficult to study- no
  direct fossil evidence!
• Adaptation, by-product or random genetic
  variation?

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Example Bipedal locomotion in humans

• Variation early hominids showed variation in
  their posture
• Inheritance This variation was under genetic
  control, and was passed from parents to offspring
• Selection Individuals with more upright posture
  survived longer and produced more offspring
• Adaptation Thus, upright posture made us better
  adapted to our environment (physical and social)

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Tinbergens 4 WhysExample Human Language

• Mechanistic (or proximate cause)
• Developmental (or ontogenetic)
• Historical (or phylogenetic)
• Functional (or ultimate)

Have a go at working out the 4 whys for bird song!
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Study of human behaviour

• Human behavioural ecology (HBE) focuses on
  behavioural traits that promote differences in
  fitness between individuals (i.e. leave more
  offspring)
• Evolutionary psychology focuses on what has
  shaped the human psyche over evolutionary time
  and whether our psychological mechanisms are
  designed to solve adaptive problems (e.g.
  detecting cheats)

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Evolutionary Psychology

• 1. Problems humans encountered in the ancestral
  environment
• a) Finding a vigorous healthy mate
• b) Forming reciprocal co-operative relationships
• c) Avoiding brother-sister mating
• 2. Psychological tools that evolved to help solve
  those problems
• d) Vigourous dance/sports indicating health
  strength
• e) Detecting cheaters in these relationships
• f) Adult sexual aversion to childhood intimates
• 3. The way those tools function now
• g) Vigorous movements in dance sport
• h) Gossip that helps us learn about cheaters
• i) Shim pau marriages, kibbutzim sexual
  attraction, attraction between brothers sisters
  reared apart

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Environment of Evolutionary Adaptiveness (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.

• Stone age minds in modern world??? Perhaps some
  of our behaviour is not adapted to modern day
  living.

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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

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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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http//www.pbs.org/wgbh/evolution/library/01/6/l_0
16_08.html

• Meredith Small and Geoffrey Miller on MHC complex
• 3 mins

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Little people

• http//www.pbs.org/wgbh/nova/sciencenow/3209/01.ht
  ml