Psychology

Unit 2 – Biological Approach

Basic Assumptions

1. Our behaviour is a result that we process from conception. 2. Our behaviour is controlled by the activity in the central nervous system,

specifically the brain.

Content

Role of Central Nervous SystemThe central nervous system is made up of the brain and the spinal chord. The brain contains nerve cells called neurones which pass around information. It then uses the nerve cells in the central nervous system to communicate with the rest of the body.

Neurones:

Neurones communicate with each other through the synapses. Neurones have an electric charge and send neurotransmitters through the synapses. This allows the brain to process thoughts and memories. Neurons both receive and transmit information; they receive information through the dendrites (a finger-like, branching structure) and they transmit information to other neurones through the axon terminals (another finger-like structure on the opposite end of the cell to the dendrite). On the end of the ‘branch structures’ are the synapses.

Synapses:

Synaptic gaps are the small junctions in-between the dendrite and the axon terminal, where neurotransmitters are transferred.

Gender Development Explanation

Role of Genes

Genes are made out of DNA. They are contained in chromosomes which are found in the nucleus of a cell. We inherit 23 chromosomes from each parent. This explains why we share behavioural and physical traits with family members. 22 of these chromosomes dictate many of our traits such as; eye + hair colour, features, etc. It is thought that they have an influence on our personalities. However, the remaining chromosome pair determine gender. For a female, the final pair of chromosomes would be XX but for males, the final pair would be XY as the Y chromosome needs to be present for a foetus to develop into a male.

At 6 weeks into the pre-natal development, the gonads (sex organs) begin to develop but there isn’t yet a difference between developing male or female sex organs.

Further on in the development, the gonads begin to develop differently on whether they are male or female. A gene in the Y chromosome called SRY produces a protein called ‘testis determining factor’. This turns the developing gonads into testicles (male sex organs) instead of ovaries (female sex organs).

Role of Hormones

The role of the Y chromosome is to ensure that the sex organs of males develop into testes rather than ovaries, so that the male will then be exposed to male rather than female hormones.

Hormones are produced in testes and ovaries and exposure to them before and after birth is the reason for physical differences seen in males and females. An example of a female hormone is Oestrogen and an example of a male hormone is Testosterone . Testosterone, when released in the womb, causes the development of male sex organs (at 7 weeks) and acts upon the hypothalamus which results in the masculinization of the brain and when Oestrogen is released it causes female sex organs to develop. Testosterone also causes behavioural predominantly traits such as aggression, where-as Oestrogen causes more emotional behaviour, which is seen more as ‘male behaviour’.

Brain LateralisationThe brain is divided so that there is the right hemisphere and the left hemisphere:

The left hemisphere controls: speech, language and comprehension, analysis and calculations, time and sequencing, recognition of words, letters and numbers.

The right hemisphere controls: creativity, spatial ability, context/perception, recognition of faces, places and objects.

It is thought that females tend to use both sides of the brain equally, and males seem to use the right side of the brain more. This is because it is said that the corpus callosum (a large network of fibres connecting the two hemispheres) is larger in female brains. This goes onto suggest that male brains are more lateralised (refers to using only one side of the brain). Males are generally thought to be better at spatial ability tasks as these are controlled by the right hemisphere.

Evaluation of Gender Development Theory

• The theory is supported by the David Reimer study. David Reimer was chromosomally a male but was brought up as a female due to a circumcision incident. However, a female upbringing wasn’t enough for Reimer to develop fully as a female and he soon started to showed many masculine traits. Ultimately showing biological factors have an influence.

• Much of the research that is used to support this gender theory is gathered from animal research, this is a strength as animal testing is cheap, quick and convenient to perform, mainly because they are performed on mice and rats which are quick and easy to breed.

• The supporting study of David Reimer lacked ethics as Dr. Money caused David/Brenda and his brother lots of stress during the study, therefore the ‘protection of participants’ ethic was breached .

• The theory is contradicted by the learning approach’s explanation which suggests that we learn our gender through observation and reinforcement.

• Daphne Went is a pseudo-hermaphrodite and refutes the explanation as she has the Y chromosome but has lived her life as a successful woman. The Y chromosome is meant to be a factor that determines male development however in this case, it hasn’t had an effect.

Studies

Gottesman & Shields Schizophrenia in Twins (1966)

Aim: To investigate the relationship between genetic make up and schizophrenia. Procedure:The research method used was twin studies with a sample size of 57 pairs of twins were used (24 monozygotic) (33 dizygotic). Researchers studied both monozygotic and dizygotic twins where at least one of the twins had been diagnosed with Schizophrenia. Results:The study found that the concordance rate of schizophrenia in monozygotic twins was 42% and the concordance rate for dizygotic twins was 9%. Conclusion: There appeared to be a genetic component in the cause of schizophrenia. Genes are an important factor in the cause of schizophrenia. Evaluation:•Sampling methods were controlled to ensure that the twins were separated in the two categories MZ and DZ twins. •The study is reliable in that it’s results support that of previous studies, showing that studies regarding genetic links between schizophrenia are repeatable•The study supports biological explanations for behavioural traits including conditions such as schizophrenia or autism. •Twins share the same pre-natal environment for a long time, which could prove that environmental factors also play a part on the cause of schizophrenia. •Although the study does provide a link between genes and schizophrenia, it fails to give any more detail on schizophrenia whether there are different types. •The results aren’t representative of the whole population as it only uses twins, therefore it doesn’t explain how people who don’t have a twin develop the disorder.

Dr Money’s Study of David Reimer Aim:

To test Dr. Money’s ‘gender neutral’ theory by seeing whether Brenda would fully develop into a female by having a female upbringing, despite being chromosomally a male.

Procedure:

The study was a longitudinal study with a sample of one participant. After seeing one of their two twins go through a circumcision incident at the age of 7 months, the mother and father of Bruce Reimer contacted Dr. Money who told them they would be better off raising their child as a female. Money would frequently meet with the twins (especially Brenda) to see how well the experiment was going. Brenda was brought up as a girl but displayed masculine traits further into her childhood. She also had many behavioural and emotional difficulties. Because of this, Money decided to end the study when Brenda was 9 years old and at the age of 15 she decided to live life as a boy.

Conclusions:Dr Money wanted to try to prove that biological gender can be easily overwritten by the upbringing of a child, however he supported the counter argument that biological gender is more determined of the child’s sex role. Evaluation: The study has ecological validity as it was longitudinal which meant that Brenda was analysed in an every day environment. The study used a volunteer sample as Brenda’s parents approached Money, therefore they had subsequently given informed consent, giving the study good ethics. When Money met with the twins, he gathered quantitative data as he asked Brenda about her likes, dislikes. These were factors which could be measured and therefore compared with the likes dislikes of her brother Brian. Dr Money caused Brenda and Brian a severe amount of stress during their meetings meaning the study breached the protection of participants ethic. The results aren’t representative of the whole population as it was a very unique case study. As the study was a longitudinal case study, it was difficult to control the extraneous variables.

Key Issue:

Is Autism an Extreme Male Brain Condition?

Description:

Simon Baron Cohen came up with the theory that autism is an extreme male condition because he found from research that most autistic people were males. The brain structure of an autistic person is an exaggeration of normal male brain structure. Baron-Cohen argues that there are many similarities between the brain structure of an autistic person and the brain structure of a normal male meaning it is predominantly a male condition.

Application:

1. Male brain structure is different from female brain structure.

• The normal male brain is heavier than a female brain because males are generally heavier than females. Autistic people have an even heavier brain than a normal male brain.

• Normal males have a smaller corpus callosum than normal females. In autistic people, the corpus callosum has been found to be even smaller than in normal males.

2. Male brain function is different from female brain function.

• Males are generally stronger at spatial tasks such as map reading than females and tests with autistic people show that they seem to be even better at spatial tasks than normal males.

• Males find it harder to develop language than females do and people with autism are very slow at developing their language.

Evidence of PracticeAim:

To investigate whether gender has an affect on spatial ability.

Procedure:

Laboratory experiment with a opportunity sample of 20 16-19 year old participants (10 female, 10 female). An independent groups design was used and participants were asked to complete a spatial awareness task and were timed for 90 seconds. After they had completed the task they were debriefed.

Results:

A man-whitney test was performed and found that the observed value, when compared to the critical value, showed a significant result, accepting the hypothesis.

Evaluation:

• A lab experiment was used which ensured that us researchers had control over extraneous variables, increasing reliability of results.

• The test was representative of both genders as male and female participants were used.

• We debriefed the participants after they had completed the task, therefore the practical’s ethics were good.

• The study lacked ecological validity as it was a lab experiment meaning participants were in an artificial environment.

• The participants used were 16-19 year old college students, therefore the results aren’t representative of the whole population.

• The practical generated quantitative data, which lacks detail and depth therefore us researchers could not get a detailed representation of the participant’s attitudes and feelings.