Biological Approach

These revision cards covers the entire Biological Approach including 

- Key Issue: Gender Re-assingment Ops

- Practical 

- Gottesman & Shield (1966)

- Money (1975) 

  • Created by: Emma Bunn
  • Created on: 13-04-14 17:47

Assumptions -

The Biological Approach is the most scientific Approach and is based around two assumptions

These are:

  • Genes affect the behavioural characteristics we show as Humans
  • Our behaviour is influencedby our physiological systems and processes

The Biological approach looks at the role of the Nervous Systems, Hormones, Genes and Brain Lateralisation/development on our behaviour

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The Role of the Nervous System on Human Behaviour

  • The central nervous system (CNS) - consists of two main parts: the brain and the spinal cord. 
  • The Peripheral Nervous system - consists of a network of neurons which carry information from the body to the CNS (The PNS works in conjuction with the CNS)
  • Neurones - Nerve cells within the brain that pass information around the body 
  • Sensory Neurones - Recieve input information
  • Motor Neurone - Carry output information
  • Neurotransmitters - one-way Chemical messengers
  • Neurotransmitters are passed via synapses from the Axon Terminal to the Dendrite of the next Neurone 

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The Brain - Localisation & Lateralisation

  • The brain is made up of a vast interconnected number of Neurones
  • It recieves inputs through Sensory Neurones and outputs via Motor Neurones
  • The brain is organised by function, it has regions devoted to different roles - this is called Localisation
  • The brain works contralaterally - The LHS of the brain controls the Right side of the body (and vice-versa)

Brain Lateralisation - the extent to which each hemisphere of the brain is involved in different activities.

LHS - analytical & verbal functions

RHS - creative & spatial functions

  • Male minds are more lateralised - using one side of the brain 
  • Female's minds are Bilateralised -The ability to use both hemispheres
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The Role of Genes on Human Behaviour

Our genes are individual biological characteristics that we inherit from our natural parents and also those evolved biological characteristics that we commonly share.

They influence behaviours and characteristics that we share as humans and influence our individual development; physically and psychologically. 

  • A gene is a region of DNA that controls hereditary characteristics.
  • Human inherit 23 chromosomes from each parent - 46 in total 
  • The 23rd pair determines gender
  • A genotype is the genetic potiental at birth and a phenotype is the actual result due to life experiences.
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The Nature-Nurture Debate

The Biological Approach supports the Nature arguement of the Debate 

Some psychological characteristics that are thought to be influenced by our Biology are also thought to be influenced in part by environmental factors.

This has lead to an on-going debate about whether our behaviour is determined by genetics and inheritance or whether our environments socialise us to act a certain way

Twin and Adoption Studies are used in this debate to help support the Nature Arguement and also they provide an insight on the influence of genes on behaviour.

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The Nature-Nurture Debate

Twin Studies - 

  • Identical Twins are called Monozygotic Twins
  • They have identifcal genes - their genes are 100% the same and they'll always be the same sex.
  • Non-identifcal Twins are called Dizygotic Twins; they come from 2 fertilised eggs.
  • The DNA between them is as similar as it would be between siblings

Twin studies compare MZ and DZ twins to see if MZ twins are more likely to share that characteristic than DZ twins, if they are it suggests genetic factors may play an important role in the determining of that characteristic.

If a characteristic is genetic, the MZ twins should both show it.

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The Nature-Nurture Debate

Twin Studies -
Gottesman & Shield (1966) -

To investigate the relative importance of environmental and genetic influences on the development of schizophrenia by comparing MZ and DZ twins

57 twin pairs

Records of twins from a Psychistric Hospital provdided a sample of 392 patients of same-sex twins, born between 1893-1945 who had survived to age 15+ 
As well as hopsital diagnosis other documentation was gathered -

  • Case Histories/Backgrounds
  • Self-report questionnaires
  • Interviews
  • Personality Tests
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The Nature-Nurture Debate

Findings -
Analysis of the data has looked for similiarities between each client and their twin. Concordance was assessed in 3 different ways:

  • Both client & co-twin have been hospitalised & diagnosed with schiz - MZ (42%) & DZ (9%)
  • Both client & co-twin have had psychiatric hospitalisation but co-twin has different diagnosis - MZ (54%) & DZ (18%)
  • The co-twin has some psychiatric abnormality - MZ (79%) & DZ (45%)

Conclusion -
Genes appear to play an important role in schizophrenia because the concordance rate is higher in MZ twins than DZ twins.

  • MZ - 42%
  • DZ - 9%

However environmental factors must also be important as the concordance rate is not 100% - meaning genetics cannot be the only influence

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The Nature-Nurture Debate

Gottesman & Shield - Evaluation

  • This study is reliable - for example, Inoyue dounf a 74% concordance rate for those with progressive schizophrenia, and a 39% C-rate when twins had mild-schizophrenia - which is similar to Gottesman & Shield's results.
  • Valid - For example, issues such as sampling were dealt with very carefully so it was understood which twins were included and why
  • Isolated Genes as a contributory factor: Valid - MZ & DZ twins both share their environment 

Weaknessses -

  • Difficult to determine cause and effect - C-rates only notes whether both twins have the disorder. Not the severity of the disorder
  • Raised more questions - it shows some genetic link, but fails to give any other explanations for schizophrenia (links to C-rate - not 100% = other contributory factors must be present)
  • Does not eliminate environmental factors - not 100% C-Rate & MZ twins are likley to be treated more alike than DZ twins
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The Nature-Nurture Debate

Adoption Studies - 

Adoption studies are carried out because the environment of adopted children is not the same as that of their biological families but they have similar genes.

Adopted children don’t share their environment with their biological families. Therefore if there are similarities with their biological families, it is likely to be because of genes.

An example of an adoption study is Kety et al (1994). They carried out an adoptive family study and found evidence for a genetic cause of schizophrenia.

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The Nature-Nurture Debate

MZ twins Reared  Apart -

MZ twins who have been separated at birth and brought up apart

  • This is a way of controlling the fact that MZ twins, as well as sharing 100% of their DNA, are usually brought up in a very similar environment
  • If MZ twins reared apart share characteristics, it can be more certainly claimed that those characteristics have a genetic basis.
  • An example of a study is Bergmann et al (1988) - they found that way the environment affects you, depends on your genetic make-up.
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The Nature-Nurture Debate

Adoption Studies & MZ twins reared Apart Evaluation -

Strengths -

  • If twins are reared apart it is easier to see if similarities are genetic because they were brought up in different environments - concluding that GENETICS are a contributory factor
  • Bergmann et al (1988)
  • Kety et al (1994)

Weaknesses -

  • Twins when adopted or reared seperately often show similar experiences in their environments as adoption agencies try to find similar families for the twins - meaning any similar traits could be due to upbringing
  • Hard to generalise from results as the sample size is small & and so not always applicable
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PET & MRI Scans

PET Scans -

  • A PET scan is used as you are able to see a working brain and its functions & a PET scan is quicker than an MRI scan
  • Procudes a 3D colour scan 
  • A way of seeing a picture of working brain
  • It shows the function of the brain
  • Can show malfunction in the brain, helping to identify damage or tumors

Patients are injected with a radioactive tracer

When the positrons are emitted, they collide with electrons forming gamma rays - which are detected by the scanner to produce an image of the acitivity in the brain.


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PET & MRI Scans

PET SCANS: Strengths -

  • Reliable as thy are replicable and the same areas are highlighted
  • Valid as their findings match other findings and they measure what they set out to measure
  • Quick and useful

Weaknesses -

  • Injection can be distressing 
  • Hard to pin-point exact areas of the brain, so they are fairly broad in their imaging

MRI SCANS: Strengths -

  • Scientific, reliable and replicable
  • They are valid in that what is found in the scans is real

Weakness -

  • The injection and scan are uncomfortable
  • Only certain information can be found from MRI's - limited
  • Lengthy procedures
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PET & MRI Scans


  • A way of seeing a picture of the brain inside the skull, like an x-ray
  • Allows you to see the structure of the brain & whether there is damage/treatment is needed
  • The patient is put into a very large scanner which passes a strong magnetic field through their head allowing a detailed picture of the brain to be produced onto the computer.
  • Electromagnetic waves are passed through the body by the magnet
  • A very detailed picture in cross-sections of the brain is produced




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Research Method - Animal Experiments

Genes -
Rats have been used to study Parkinson’s disease and gene therapy. Researchers used drugs to replicate in rats the symptoms of Parkinson’s disease. They then used gene therapy to try and reverse the symptoms, with some success.

Nervous System - Brady (1958)

Using monkeys was carried out to see if control over a situation affected stress levels. Some studies showed that having control over a situation can be stressful and some showed that not having control is stressful. Therefore, the conclusions are uncertain.

Functions of the Brain - Rechstraffen (1983)

Rats have been used to find out the effect of sleep deprivation

They not only became distressed, but after 33 days all the rats had died due to sleep deprivation

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Research Method - Animal Experiments

Animal Experiments -
Animals can be used to study genes, the nervous system and functions of the brain

Grey (1987) - helped to show that it might not be as unethical as previously thought to use animals in studies, therefore he said it's better to use them to help us

Bateson's Decision Cube - if animal suffering is low, scientific quality is high and the benefit to humans is high then an study is ethical to carry out

Animal Research Guidlines state - Home office license required, anaesthetics used were possible, suffering kept a minimum, alternatives should always be sought and restraints should only be used if there is no alternative.

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Research Method - Animal Experiments

Ethical Strengths -

  • Procedures can be carried out on animals that aren't ethical to carry out on humans - Ablation
  • Grey (1987) - Pro-speciesism - improving quality of life by whatever means 

Ethical Weakness -

  • Animals are confined more than normal & in an unfamiliar environment or are bred for the purpose 
  • Surgical procedures are used, which is likely to cause the animals pain and usually leads to death
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Research Method - Animal Experiments

Practical Strengths -

  • Most animals used are small and easy to handle
  • Some animals have similar brain structures/chromosomal functions to humans, which is useful for comparative purposes.
  • Quick gestation periods = easier to study one generation at a time

Practical Weaknesses -

  • Animal exps are not 'real-life situations' = poor face validity 
  • Animals are not the same as humans = ANTHROPOMORPHISM
  • Some diseases have to be artificially reproduced and therefore this isn't the same as a human developing it, unvalid.
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Money (1975)

Aim -
Money aimed to test whether or not gender could be learned through upbringing
He believed that all children were born/gender neutral and are created as males/females through social experiences

Procedure -

  • Bruce and Brian were born in 1965, and at 10 months they were circumcised
  • During Bruce's procedure he penis was badly burnt and left unrecognisable.
  • At the age of 22 months, Bruce was surgically castrated and his name was changed to Brenda. He was dressed in girl's clothes and encouraged to be stereotypically female
  • From the age of 12, Brenda was given Oestrogen to promote female puberty
  • Brenda's transition to female hood was not easy and she was often described as having very mascluline traits.
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Money (1975)

Procedure -
She has many behavioural and emotional problems
At the age of 12 she was told the truth.She decided to live as a boy and became known as David, undergoing a phalloplasty to create a penis in 1981



  • In their thirties, Brian (Brother) committed suicide which cause David to blame himself and lead to the development of depression and becoming withdrawn. 
  • Age 38, David committed suicide.

Conclusion -

Whilst Dr Money had set out to prove that biological sex can be overridden by upbringing, he actually seems to have supported the counterargument that biological sex is more a determinate of a child’s sex role and therefore that biological factors are more important.

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Money (1975)

Strengths -

  • It was possible to compare the behaviour of MZ who share the same genetic make-up but have different experiences, meaning there was a good matched control to compare Brenda’s behaviour to.
  • Both boys developed as males even after having different upbringings, providing strong support for gender being determined by biological factors.
  • The case study is detailed and in depth, meaning it has some validity.
  • The data used was from more than one source, so it can be said to be reliable.

Weaknesses -

  • Controversy over the decision - it was done because it’s easier to construct a vagina rather than a penis. More thought should be given when deciding how to raise an intersex child.
  • Claimed to be measuring something that it eventually didn’t measure, meaning little validity.
  • Poor Ethically - The stress lead to both twins suicide, mothers attempted suicide and their fathers alcoholism.
  • Unique case, making it hard to generalise.

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Gender Development

Gender - the mental development and behaviour of an individual of a person
Sex - Biologically male or female

Asschaffer (1993) pointed out, later research has indicated that there are some other gender differences in behaviour.

  • Girls are more emotionally sensitive than boys
  • Girls have less developmental vulnerability than boys

Maccoby & Jacklin (1974) - conducted a study and identified 4 biological differences between males and females -

  • Girls have greater verbal ability than boys
  • Boys have greater visual & spatial awareness than girls
  • Boys have greater arithmetical abilities than girls
  • Boys are more physical and aggressive than girls

There is evidence to suggest that girls are doing better educationally than boys - in 2000, 61% of girls achieved A*-C compared to 51% of boys.

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Gender Development

The Role of Genes -

  • We all inherit 23 pairs of chromosomes from each parent.
  • 22 of the 23 pairs determine physical appearance but the final pair determines gender
  • Females = **
  • Males = XY (Y-chromosome from Father)

1-3 Weeks - Every Feotus develops identically 
6 Weeks - Gonads develop (gender-neutral sex organs) which produce sex cells & hormones

6-8 Weeks -

  • The default setting for all foetuses is to develop into a female
  • If Y-Chromosome is present then the SRY gene (only present in a Y-C) will release a protein called 'Testis-Determining Factor' - which causes the gonads to develop into testicles rather than ovaries.
  • If there is NO Y-Chromosome = Female development will occur
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Gender Development

Fetal Development -

  • Hormones act to enable the different sexes to develop - Anti-Mullerian Hormone prevents the growth of the Female Mullerian Ducts in males
  • Androgens are secreted and affect the growth of Wollfian Ducts (Male genital system)
  • External genitalia remain feminine in the absence of androgens 
  • In males, androgens allow the masculine external genitalia to develop.

Abnormal Sex Differentiation -

Turner's Syndrome - affects 1 in 2500 girls. It is caused by a missing X chromosome -- sufferers tend to be short and have un-functioning ovaries (infertile) & don't develop breasts.

Klinefelter's Syndrome - affects 1 in 500-1000 boys. Sufferers have XXY chromosomes meaning they have smaller testis and often develop breasts. 

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Gender Development - The Role of Hormones

From the point at which the Gonads of a feotus have formed, the influence of genes on gender development ceases.

Gender Specific Hormones help to enable the different sexes to develop.
Exposure to sex hormones has a permanent effect on the development of sex organs.

6 WEEKS - H-Y (Testis-Determining Factor) protein is released - this encourages the development of the Wolffian System & the testes.

HORMONES also have an influence 2ndary sexual characteristics - PUBERTY = gender correct hormone is released.
Testosterone = produces sperm, facial/pubic/armpit hair etc
Oestrogen = Menstruation cycle, breast development etc.

Androgen Insensitivity Syndrome - 
The individual's body doesn't respond to the effects of the androgen and develops the Female Mullerian System.
Testes develop but no further masculine development occurs = FEMALE GENITALIA DEVELOPS

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Gender Development - The Role of Lateralisation

Women tend to be BILATERAL - able to use both Hemispheres of the brain
Men tend to be UNILATERAL - only able to use one Hemisphere at a time

Due to Men being Unilateral, this means that they are affected more during strokes/brain damage

Rossell et al (2002) - found that with a real/fake word test, men were faster if the word was seen to the right and women to the left. Brain scans showed that in men, the response came from the left H whereas in women both sides of the brain were active. 

Jeager et al (1998) - found from PET scans that during langauge processing, although speed and accuracy were similar, men used their left hemisphere and women used both sides.

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  • The case of David Reimer shows that gender is biologically determined, not socially constructed as he was born male and no one else knew, but everyone said he was masculine. His biological status as a male was strong enough to override his upbringing as a female.
  • Evidence from animal research suggests that gender is determined by biological factors. Pfeiffer (1936) removed sex organs from rats and found that female hormones were released but with testes still on the rats, male hormones were released. Showing the presence or absence of testosterone accounts for sex differences, which is biological.
  • Evidence is strong as it’s both qualitative and quantitative. It shows case study evidence from humans and laboratory evidence from animals. This gives the theory validity (human evidence), reliability (similar results), it’s scientific (experiment) and it’s holistic (wide type of evidence).
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Strengths -

  • This explanation has face validity as the genitalia of a child when their born determines how they are treated. This is biological.
  • Problems with hormones emphasise the role that they play on gender development and therefore support biological explanations of gender.
  • Special cases such as the Batista family illustrate the central role of genes on gender development. The Batista family changed biological gender, which overrode what female behaviour they had learned. This showed that biological factors were more important.
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Weaknesses -

  • Problems with hormones illustrate that genes don’t ultimately determine genetic sex as hormones can override this. Hormone problems can occur through environmental exposure to hormones such as steroids in the womb. This shows that gender is the result of a complex interaction between biological and environmental factors. Biological explanations are reductionist (ONLY 1 side) and are deterministic (fixed).
  • Other research has been done on humans in the form of case studies (David Reimer). This is weak as they are very specific and can’t be generalised.
  • Psychodynamic approach provides an alternative explanation. Freud says childhood experience causes you to be male or female. Especially the phallic stage (4-6) and overcoming the Oedipus/Electra complex.
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Weaknesses - 

Social Learning Theory is another alternative explanation. It says that children observe and imitate the behaviour of same sex role models and are reinforced for showing gender appropriate behaviour by being praised and encouraged.

Much of the research to support this approach has been done on animals. This is weak as it’s not safe to use information from animal research in order to explain human behaviour as there are too many differences.

Evidence from cases of pseudo-hermaphrodites (both genders) criticises this approach as they can successfully live as a gender different to their genetic sex. Daphne Went (C:M A:F) lives as a female despite having a Y chromosome. Therefore, upbringing is most important.

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Key Issue - Are Transgender Operations Ethical?

Transgender Operation = Surgically Reassigning Sex  

Adults undergo these op's as they may feel they were born into the wrong body/gender.

Transgender Op's are conducted on children when they are born with an indeterminate gender (characteristics of both genders - HERMAPHRODITES


  • Informed consent needed
  • Patient should be fully briefed about the procedure and possible consequences
  • High chance that the op will be successful
  • Should be undertaken in the best interests of the patient and should be more beneficial than harmful

For a transgender operation to be truly successful it has to be done in infancy when the body is still developing so that the sex organs are fully functioning.

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Key Issue - Are Transgender Operations Ethical?

Reiner & Gaerhart -
Conducted a study on 16 genetic males born without (micro) penises bu with normal testes and XY chromosomes.
14 of these were raised as girls after surgery but most of those still felt male and showed very masculine traits e.g. fighting, aggression etc. 

It is easier to create a working vagina and feminise a body than it is to create a working penis - it is thought that this fact is what drives decisions over which gender an intersex child should be reaised as.

Strengths - (Agrees that T-Ops are Ethical)
Money, Hampson & Hampson (1995) -

  • Studied 131 intersex patients (ranging in age)
  • More than 95% of the people developed equally well psychologically no matter what gender they have been raised.
  • Therefore, supporting that upbringing is more important than biological factors 

Kim Petras - Born a male, but during childhood felt female. At the age of 12, he started receiving female hormone injections and at the age of 16 had a T-OP. 

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Key Issue - Are Transgender Operations Ethical?

Weaknesses - Evidence to support the AGAINST arguement.

Money (1951) -

  • Reviewed over 250 cases of intersexes who recieved no surgical intervention as babies.
  • It was found that the majority of thses patients rose above their genital handicap and lived in a way virtually indistinguishable from people without genital difference. 
  • This supports that genital abnormality isn't enough to justify gender change - unethical 
  • Unsuccessful sex change operations include Renee Richards who at the age of 40 underwent transgender operations (1975).
  • Changed from a male to female but wasn't warned about the way her face would still look masculine and was bullied because of it. 
  • She was never accepted by either gender and labelled a 'transsexual' instead of female and therefore advised EVERYONE she spoke to, not to the change as it was the worst mistake she has ever made - UNETHICAL 
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