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AS and A Level: Physiological Psychology
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Five physiological approaches to research
- 1 Genetic – seeks to establish the extent to which traits are due to inheritance or environment. Researchers study concordance rates (if one person has a trait or disorder, what is the percentage probability that the relative also has it?) using twin, adoption and family studies e.g. susceptibility to stress.
- 2 Evolutionary – seeks to establish continuity between human and other species and explain human behaviours in terms of ecological adaptation, maximising survival and reproduction. Look out for studies on primate or other mammal behaviour that are used to draw conclusions about causes of human behaviour e.g ecological theories of sleep.
- 3 Neuroanatomical – seeks to understand the relationship between brain structure and behaviour. Often uses case studies of people with damage to certain parts of the brain or post-mortems of people with abnormal behaviours e.g. case studies of amnesiacs.
- 4 Psychobiological – related to the previous approach, but with more of a focus on measuring brain activity using a variety of scanning techniques whilst the individual is engaged in a specific task or activity. Often used for comparisons – eg. the brain activity of diagnosed psychopaths compared against the brain activity of ‘normal’ participants.
- 5 Biochemical – related to the previous approach, but with more of a focus on assessing the levels and activity of specified neurotransmitters or hormones and drawing correlations with specific mental states or behaviours e.g. post-natal depression, changes throughout the menstrual cycle.
Five big ideas for physiological psychology essays
- 1 Consider the causal nature of research findings – On the other hand, studies that do involve manipulation of an independent variable may require so much control of extraneous variables to produce a robust causal relationship that they can be criticised as being artificial and reductionist.
- 2 Consider the scientific nature of claims – Assess the extent to which explanations are supported by scientific research or not. Evaluate the techniques used by psychologists to operationalize mental processes in their research. For example, behavioural responses and psychobiological measures don’t tell us about the nature of thoughts.
- 3 Consider determinism – The more scientific the approach, the more determinist it tends to be, because science is the search for causes. Seeking ultimate causes of behaviour or chains of causal links is incompatible with the idea that humans have free will and complete moral responsibility.
- 4 Consider reductionism – Reductionism is the principle that one should always seek to understand at the most basic, most fundamental level: e.g reducing our understanding of depression to an explanation about the balance of chemicals in the brain rather than looking at the whole person in their social context. As a rule, the more scientific the approach, the more reductionist it is. Reductionist explanations have the benefit of being able to provide straightforward practical solutions.
- 5 Consider the correlational nature of research– Much physiological research is correlational, because it can be unethical to manipulate variables when studying topics such as the relationship between stress and the immune system or extreme sleep deprivation. Such studies can never produce a conclusive causal explanation, no matter how much we would like them to!
Four common brain imaging techniques
- 1 fMRI – Functional Magnetic Resonance Imaging measures brain activity by measuring blood flow and oxygenation within the brain. When neurons are active they use more oxygen - so higher blood flow in a particular area signifies increased neural activity. fMRI scans are useful for studying the localisation and level of brain activity.
- 2 CT– A Computerised Tomography scan builds up an overall picture of the brain based on the way that X-rays are absorbed. Bone and hard tissue absorb more x-rays, soft tissue absorbs less, fluid absorbs very little. CT scans show the main features of the brain but are not so useful for looking at detailed structures.
- 3 PET– Positron Emission Tomography uses tiny amounts of radioactive material with very short half-life to map functional processes in the brain. When the radioactive material decays, a positron is emitted and this is detected on the scan. Higher radioactivity is associated with higher levels of brain activity.
- 4 EEG – Electroencephalography involves measuring the electrical activity of the brain with electrodes attached to the scalp and coverting the level of activity into an electroencephalogram, which shows the amplitude and frequency of brain waves. EEGs are frequently used in sleep research because it is a non-invasive technique, which can detect minute millisecond length changes in overall brain activity and arousal level.
The findings of this experiment were that T cell activity significantly reduced in the 2nd blood sample. Analysis of the blood test also found that levels of T cells were most reduced in participants who had high levels of life events and loneliness had the most reduced levels of T cells. From this experiment we can conclude that stress reduces immune function which could leave you vulnerable to illness and infection. We can also conclude that the immune system is also affected by psychological variables. The aim of Weiss et al's experiment was to see if short term stress (loud noise and electric shocks) reduced the amount of T cells subsequently weakening the immune system.
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Discuss the biological explanation for schizophrenia taking in to account genetics and brain structure
Rosenthal (1963) also found a case of female schizophrenic quadruplets. This makes the evidence for a genetic basis for schizophrenia stronger. However, they only looked at three studies, which is still a very small number. We cannot base our opinions on concordance rates because they suggest that there are other factors that influence schizophrenia, therefore it can be considered quite vague. Most twins also share very similar environments than siblings so this must also be taken into account. Particularly for early studies, sophisticated genetic testing was very difficult to distinguish MZ and DZ twins, especially at birth.
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Both studies provide consistent evidence into the effects of jet lag and are furthermore supported by other research however, there are methodological issues with the studies. Although the studies are field studies with high ecological validity they do not consider confounding variables such as individual differences e.g. the levels of performance of the baseball teams which may affect their results. Another criticism of these studies is that they both ethnocentric and androcentric as they used American and all male samples therefore the results cannot be generalised to the wider population.
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When her brother distant himself from her she became even more depressed and alone. She would than devote herself to school because she believed that ?If I couldn?t be pretty, I decided I would be smart?. She started medical school in the fall of 1906 and got married to a fellow law student in 1909. Her husband died in 1930, which caused her to move to the United States. It was there that she began her psychology theories and met prominent and intellectual friends and doctors; one of which is Freud.
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Describe the biological (medical) model of abnormality and evaluate it in terms of its strengths and weaknesses. (12 marks)
Gottesman (1991) conducted a meta-analysis of twin studies, and found that people had a 48% chance of developing schizophrenia if their identical twin had the condition. This reduced to 17% with non-identical twins. This suggests that schizophrenia could have a genetic basis. Another explanation of abnormality is that it is caused by biochemical imbalance. For example, the dopamine hypothesis suggests that excess dopamine may cause schizophrenia.
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1. However, it is argued that Mono-zygotic twins may be treated more similarly than Di-zygotic twins. Adoption Studies Researchers compare an adopted child with either a biological parent or their adoptive parent. If genetics is a major factor of aggression, then we would expect similarity between child and biological parents. (E.g. father has history of violent crimes). 1. Difficult to tell whether aggressive behaviour is due to extraneous variables. Gene for aggression Monoamine Oxidase A Gene responsible for producing a protein called monoamine oxidase A (MAOA)
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Monozygotic twins are biologically identical so if schizophrenia was solely the result of genetics than the concordance rate between identical twins should be 100%. As this is not the case the development of schizophrenia must also be due to differing environmental factors. Furthermore, it is near impossible to distinguish between genetic and environmental factors if the twins share the exact same environment. As well as this, even twins reared apart shared the same environment in the womb before birth; this includes receiving the same nutrients, oxygen and being affected if the mother becomes unwell.
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They said that ?inmates with higher testosterone levels violated more rules in prison, especially rules involving overt confrontation. Supporting that testosterone acts on areas of the brain which control aggression. However, the research lacks ecological validity because it is based on prisoners so it is not based on people doing ?normal? day-to-day activities. The study has gender bias and lacks population validity, this is because the study was only done on males so cannot be generalised to women as they are unlikely to be the same, also, because it was only done on adults it does not account for aggression in children, meaning it lacks population validity.
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The lateral hypothalamus contains the feeding centre and initiates eating behaviour. It responds to a number of things such as the decrease in blood sugar and an increase in the hormone ghrelin, which is a hormone which is produced then the stomach is empty. There are limitations of the LH. One limitation is that damage to the LH has found to cause problems with other bodily functions such as thirst and s*x. This shows that the LH may still play a part in eating behaviour but it may not be the body?s ?feeding centre?.
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This shows that there may be a correlation between the immaturity of the brain and REM sleep. By the age of 5 it is known that children have already developed EEG patterns similar to adults. However they sleep more than most adults, around 10 hours and day, they also have more REM sleep (around 30%). It is also common that a child will suffer from sleep disorders such as Sleep walking. Although childhood sees a decrease in the amount of sleep, during adolescence sleep with increase slightly, to 10-12 hours. Circadian rhythms also change. Teenagers suffer from phase delay, this means that they find it hard to get to sleep at night and find it hard to wake up in a morning.
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It reacts to the GABA receptors, making it harder for the neurone to be stimulated by other transmitters, so this slows down the activity and makes a person feel more relaxed. However there is evidence to show the effectiveness of BZs,Kahn et al (1986( found that BZs were more effective than a placebo treatment in reducing anxiety, and Hidalgo et al (2001) found that BZs were more effective than antidepressants. A limitation of using BZs is that they can cause lots of side effects for example aggressive and memory loss.
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Compare the explanations for relationship breakdown given by exchange and equity theory. Which do you consider the most convincing and why?
Another explanation for relationship breakdown was given by Walster eta al 1978 called the equity theory. Messick and Cook (1978) suggested that people strive to achieve fairness in their relationship and feel distressed if they perceive unfairness. People who give a great deal into a relationship and gets very little in return would perceive inequity and therefore dissatisfied in the relationship. However, the same applies for those who give very little in relationship but receive a great deal in return.
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Depression. I have read an article on the BBC News website asking Is living alone bad for your mental health?.
1,695 of the subjects were men and 1,776 were women. The average age of the subjects was 44.6. To obtain the relevant information needed the subjects were asked to complete a survey asking whether they lived alone, or if there were other people within their household. Environment factors taken into consideration were their income, employment, working environment, education, housing conditions and social support. Alongside health factors such as smoking, drinking habits and their exercise routine, if any.
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