1.
Debate: Nature and Nurture
The degree to which human behaviour is
determined by genetics/biology (nature)
or learned through interacting with the
environment (nurture)

2.
Aims of lesson
To understand what is meant by the nature-nurture
debate and to identify the main
assumptions .
To be able to describe at least 1 study which
supports nature, and 1 study to support
nurture.
To be able to identify the applications and
problems associated with the debate.
To be able to identify the perspectives/
approaches relevant to the debate.
To be able to evaluate the debate.

3.
Nature
 Behaviour is caused by innate characteristics :
The physiological/biological characteristics we are born
with.
 Behaviour is therefore determined by biology.
 Determinist view- suggests all behaviour is determined by
hereditary factors:
Inherited characteristics, or genetic make-up we are
born with.

4.
Nature
All possible behaviours are said to be present
from conception.
Genes provide the blueprint for all behaviours;
some present from birth, others pre-programmed
to emerge with age.
Is a developmental approach:
E.g. Piaget: children’s thought processes
change at predetermined age-related stages
changes in age are related to changes in
behaviour.

5.
Nurture
An individuals behaviour is determined by the
environment- the things people teach them,
the things they observe, and because of the
different situations they are in.
 Also a determinist view- proposes all human
behaviour is the result of interactions with the
environment.

6.
Behaviourist theories are nurture theories:
- Behaviour is shaped by interactions with the
environment.
Born an empty vessel- waiting to be filled up by
experiences gained from environmental
interaction.
No limit to what they can achieve:
-Depends on quality of external influences and
NOT genes.
The quality of the environment is KEY:
-You can become anything provided the
environment is right.

7.
Support for Nature
 Piaget- children’s thought processes change at
predetermined age-related stages.
 Changes in age are related to changes in behaviour:
- Sensorimotor (birth – 2 years)
- Pre-operational (approx 2 – 7)
- Operational (approx 7 – 11)
- Formal operational (approx 11+ years)

8.
Support for Nature
Language Acquisition (Chomsky, 1968)
- Chomsky maintained language is the result of
innate cognitive structures in the mind.
- Biologically based inborn brain mechanism
-Children are predisposed to make sounds and
understand grammar.
- This does not happen from birth but language
skills develop rapidly after a certain period of time
Language acquisition follows the same
sequence in all children= an inbuilt genetic
mechanism is responsible.

9.
Identical genes exist in Identical Twins- Monozygotic
(MZ) twins share 100% of their genes.
 Fraternal Twins- Dyzygotic Twins (DZ), share 50% of
their genes.
Genetic effects can therefore be shown when the
correlations within each group is compared with
the correlations between each group.
 This can be added to the correlations found with
other relatives. Parents share 50% of genes, cousins
share 12.5%.

10.
Support for Nature
Genetic basis of Schizophrenia (Gottesman &
Shields, 1976)
- A review of twin and adoption studies into
schizophrenia between 1967 and 1976.
- In adoption studies: compared biological
parents and siblings and adoptive parents and
siblings.
- In twin studies: compared concordance rates
(how often both twins were diagnosed with
schizophrenia) for monozygotic (identical) and
dyzygotic (non-identical) twins. Video

11.
Results Support for Nature
- Adoption studies found increased incidence of
schizophrenia in adopted children with a
schizophrenic biological parent.
- ‘Normal’ children fostered to a schizophrenic
parent and adoptive parents of schizophrenic
children showed little evidence of schizophrenia.
- Twin studies found higher concordance rate for
schizophrenia in MZ twins (58%) than DZ twins
(12%).
Conclusion
Significant genetic input into the onset of
schizophrenia. Genes responsible for predisposing a
person to schizophrenia.

12.
 IQ scores Support for Nature
-Plomin (1988) studied MZ and DZ twins reared
together and apart and found that I.Q. has an
overall heritability of 0.68- genetics are
responsible for about 68% of the variation in
I.Q.
-MZ twins reared apart have I.Q. scores which
correlate at about 0.74, or 74%.
Evaluation point
However, variations between identical twins
must
be due to environmental influences.

13.
Support for Nurture – Little Albert
Classical conditioning of fear- phobia acquisition:
‘little Albert’ (Watson & Raynor, 1920)
-Before the study little Albert showed no sign of fear
response in any situation.
Session 1: Aged 11 months, Albert was presented
with a rat. Each time he reached for the rat a steel
bar was hit.
1st time= he jumped + fell forward
2nd time= he began to whimper
Session 2: after 5 paired presentations, Albert
reacted to the rat alone by immediately crying,
turning, and crawling away quickly.

14.
Support for Nurture
Session 3: Albert returned to see if the fear had
transferred.
- Presentation of toy blocks (neutral stimulus) =
playing
- Presentation of the rat followed by a rabbit, dog,
fur-coat, Watson’s hair and a Santa Claus = –ve
responses of crying, moving away from stimulus and
crawling.
Session 4: steel bar + rat, steel bar+ rabbit, steel
bar+ dog. Fear response was pronounced in all.
Session 5: 1 month later Albert continued to show
fear reactions to all stimuli. Transference of the fear
had been made to similar objects.

15.
Support for Nurture
 Conclusion
- By session 2, after 5 paired presentations the
conditioning of fear was evident: is possible to
condition fear through classical conditioning.
- By sessions 3 & 4, transference of the fear had been
made to similar objects.
- By session 5, time had not removed the fear response.
 Provides evidence that the environment can be
manipulated to create a phobic response &
behavioural change.
(See key study: A2 OCR textbook p.115)

16.
Support for Nurture- Zimbardo
 Zimbardo (1973) Stanford Prison Experiment
- 24 participants, described as “normal, healthy male
college students, predominantly middle class and white”.
- Randomly assigned to the role of ‘prisoner’ or ‘guard’ .
- A simulated prison was built in the basement of the
psychology building at Stanford University. It comprised of
3 small cells each housing 3 men ,and 1 small unlit room
for solitary confinement.
Video

17.
Support for Nurture
Guards not told how to behave but were
explicitly told that they were not allowed to use
physical punishment or physical aggression.
Uniforms of both groups were intended to
increase group identity and reduce individuality.
 Guards’ uniforms were intended to convey a
military attitude, with a baton and whistle for
symbols of control and power.

18.
Support for
Nurture
 The behaviour of the ‘normal’ students was affected
by the assigned role- seemed to believe in their
allocated position.
Guards became verbally and physically aggressive.
 Prisoners became increasingly depersonalised-several
experienced extreme depression, crying, rage
and acute anxiety.
 The experiment had to be stopped after just six days
instead of the planned 14 days.
 The study demonstrates the powerful effect roles can
have on peoples’ behaviour.

19.
Can you think of any
other studies that show
the effect a situation can
have on behaviour?

20.
Nature Nurture Interaction
Behaviour is often a result of the interaction
between nature AND nurture.
An individuals characteristics may elicit particular
responses in other people e.g.
Temprament: how active, responsive or
emotional an infant is influences in part
determines their caregivers responses.
Gender: people tend to react differently to boys
and girls due to expectations of masculine and
feminine characteristics.
Aggression: Displaying aggressive behaviour
create particular responses from other people.

21.
Nature Nurture Interaction
Evidence
 Rutter and Rutter (1993) Aggression hostility
- Described how aggressive children think and
behave in ways that lead other children to
respond to them in a hostile manner.
-This then reinforces the antisocial child’s view
of the world. Thus, aggressive children tend to
experience aggressive environments partly
because they elicit aggressive responses.

22.
Nature Nurture Interaction
 Maguire et al. (2000)- Taxi driver study
- Structural MRI scans of the brains of licensed
London taxi drivers were compared with controls
who did not drive taxis.
- Hippocampal volume correlated with the amount
of time spent as a taxi driver
- The posterior hippocampi of taxi drivers were
significantly larger relative to those of control
subjects.
- The posterior hippocampus stores a spatial
representation of the environment and can
expand regionally in people with a high
dependence on navigational skills.
See AS Psychology textbook:
pp.68

23.
Nature Nurture Interaction
 Maguire et al. Conclusion
- It appears the brain has the capacity for plasticity
(the ability to change)- the structure of the brain
can alter in response to environmental demands.

24.
Supporting Approaches &
Perspectives
Supporting NATURE Supporting NURTURE
Physiological Social (e.g. Helping
behaviour)
Individual Differences Behavioural
Developmental
Psychodynamic

25.
Problems with Nature-Nurture Debate
1. It is reductionist
2. It is deterministic
3. It is difficult to control variables
Determinism: The ‘nature’ view of psychology
is a determinist one- it suggests behaviour is
determined by hereditary factors (e.g.
Language development).

26.
Applications
Nature
Drug therapies can be developed to treat
behavioural or psychological problems that have a
physiological origin.
E.g. SSRI’s can be used to treat depression, Ritalin-
ADHD.
Nurture
 If behaviour is susceptible to environmental
influences we need to consider how we adapt our
environment.
E.g. To promote helping behaviour, enhance
learning, reduce aggression and decrease
criminality.

27.
Summary
 Nature: behaviour is caused by characteristics we are
born with e.g. genetic, physiological.
 Nurture: behaviour is shaped through interactions with the
environment.
 Research supporting nature: language development, IQ
scores, predisposition to schizophrenia etc.
 Research supporting nurture: fear acquisition, effect of the
environment on behaviour.

28.
Summary cont...
Nature-nurture interaction: Temperament
and gender can influence other peoples
behaviour.
Exposure to certain environmental stimuli
can alter physiology e.g. Brain structure,
neurochemicals.
Applications: Development of drug
therapies,
adapt environments to increase helping
behaviour, enhance learning etc.