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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.
Stress can be explained as the stimulus in the environment that triggers a stress response. Psychologists call anything that causes someone to act stressed a stressor
'Hypothalamic-Pituitary-Adrenal Axis' 1. Evaluation of whether something is a stressor, occurs in higher brain centre (cerebral cortex) 2. When there's a stressor in the environment, these areas send a signal to the hypothalamus, which starts two processes in the body: a) Signals sent to pituitary gland, which release hormone called ACTH (adrenocorticotrophic hormone) into the blood. b) The Autonomic Nervous System (ANS) is also activated. This stimulates (arouse), adrenal medulla to release adrenaline & noradrenalin into the bloodstream. To respond successfully to a stressor, we have evolved a 'fight or flight' response.
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However, one weakness of the study above is that it only shows age-related differences in the brain structure by looking at children and adolescents - to increase its validity, it would need to follow the same group through children and adolescence to study the brains in the same group over time - therefore, minimising the effect on participant variables. However, one strength of the study is that the use of MRI scans ensures that the results are objective and not bias in interpretation.
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Although, Ogden (1994) suggested that obesity may not be caused by overeating, overeating may be a consequence of obesity if restraint is recommended as a treatment. She also suggests that if trying not to eat leads to overeating then how do anorexics manage to starve themselves? This then raises the question as to whether there are other contributing factors as to why obese individuals can not restrain their food intake and maintain a diet without eventually overeating. Research such as Kern et al; suggest that for some people, dieting will always be difficult due to a genetic predisposition of obesity.
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Outline the findings of studies into sleep deprivation and assess their implications for one or more theories of sleep.
Another case study by Randy Gardener a 17 year old student stayed awake for 11 day which resulted in disorganised speech, blurred vision and a small degree of paranoia. However after two nights longer sleep with longer spend in REM (rapid eye movement) he returned to normal sleep patterns. This show that total sleep deprivation does not have a long lasting effects on people health or sleep patterns. Both of the case studies support Oswald (1980) who claimed that none REM sleep restored the body and REM sleep restored the brain, through protein synthesis.
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This could be because of direct effects of desynchronisation or indirect effects such as sleep disruption. 2. Outline briefly jet travel and jet lag. Recht- looked at US baseball results over a three year period. Teams that travelled from east to west won 44% of their games, unlike when travelling from west to east who only won 37%. The conclusion he drew from why this occurred is because east to west is phase delay so they wake up later then they are used to. Whereas, travelling from west to east is phase advance so they have to wake up and earlier then they are used to.
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These findings strongly suggest that genetic factors are important - the reason why identical twins have a much higher concordance rate than fraternal twins is because they are much more similar genetically (50% vs. 100%). Gottesman also suggested that the concordance rate for identical twins brought up apart was very similar to that for identical twins brought up together. This suggests that the high concordance rate is not down to environmental factors in the upbringing. However this view has been challenged on several fronts.
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One strength of the research into the genetic explanation for depression comes from the empirical support it provides; twin studies in monozygotic twins and dizygotic twins provide strong evidence to suggest genetic causation for depression and other disorders such as schizophrenia ( Gottesman and Shields). For example Bertelsen found a concordance rate of 80% of bipolar with MZ twins, but a rate of only 16% for DZ twins. This evidence suggests that there is a wider academic support that genetics play a part in affective disorders such as depression.
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Outline Clinical Characteristics of Schizophrenia and discuss psychological explanations of Schizophrenia
One psychological explanation of SZ was put forward by Bateson et al (1956) who looked at childhood as a base for developing SZ, for example the interactions children have with their mothers. His explanation, the Double Bind theory, states that SZ can occur due to conflicting messages given from parents to their children, for example when a parent expresses care but does so in a critical way. This means that the child will become confused as the message they are given is conflicting, as one message effectively invalidates the other.
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A babies night waking has adaptive benefits to because a baby has a small stomach so it needs to be fed regularly. Infancy, at 6 months a circadian rhythm has been established, and by the age of one year infants are usually sleeping at night with fewer naps during the day. The period of deep sleep lengths and active/REM sleep shortens. It is not know whether REM sleep in babies means dreaming as babies and infants are not reliable subjective reports.
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There are 5 different stages in sleep. 4 NREM stages of sleep and the fifth is REM sleep. S One sleep cycle goes through 5 stages of sleep which lasts around 90 minutes. Stage 1 and 2 sleep stages are light sleep characterised by Alpha and Theta brain waves heart rate slows and temperature drops. Stage 3 and 4 sleep are characterised by Slow Wave Sleep (SWS) in this state it is harder to wake someone up, delta brain waves are produced , metabolic rate slows and growth hormone is produced.
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morning * Tests in cold water lower IQ * rough at midday which is reflected in siesta (sleep interaction) Evaluation * Alertness is highest when temperature is lowest * Field study found no such correlation Infradian Rhythms - more than 24 hours SAD * Depression rates higher in winter months * Unsure cause, best attempt due to lack of light = imbalance melatonin which interferes with neurochemicals causing depression * Was suggested that artificial light could reverse these effects by manipulating circadian sleep / wake cycle * Pps with SAD received 30 min exposure to bright light improved 5% vs.
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Is it more stressful to lose your leg in a car accident or travel on a packed bus to school every day?
There are also a lot of other factors that could cause stress that are to be considered. The person will be damaged physically, mentally and socially therefore bringing down their overall health. The World Health Organization defines health as 'a state of complete physical, mental and social well-being'. Losing a leg is more then it seems, being permanently disabled and unable to perform a lot of everyday tasks will increase stress; a disabled person has less control of their life and will have to rely more on other people and equipment, this leads to more stress and possibly a stress related illness .
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He believed that an adaptive mechanism calculates salt preferences as a function of the risk of dehydration as indicated by past experience of dehydration and maternal salt intake. There has been no key research to support Fessler's theory and so it may not be reliable in explaining why humans incorporate salt in their diet. Salt is also key for animals as high sodium concentrations maintain the body's nerve and muscle activity and water balance. Dudley et al (2008) found that ants prefer salty snacks to sugary ones in inland areas that tend to be salt poor.
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People who are stressed often get ill; discuss research into the relationship between stress and physical illness.
Selye's model of stress is known as the General Adaption Syndrome or GAS. GAS consists of three stages 'The Alarm Stage', this is when an organism first encounters a threat, it responds with what is known as the "fight or flight" response, this consists of a, an increase in - adrenaline secretion, respiration rate, heart rate, blood pressure and muscle tension. The digestion rate lowers or decreases, the pupils dilate, a release of stored sugar to give an organism extra energy and an increase in blood coagulability.
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Corticosteroids' have the basic function of suppressing our immune response system and facilitating the conversion of fat into glucose and fatty acids for energy. It is the long-term arousal associated with stress hormones that causes a variety of effects on the body, which may become pathological and eventually lead to illness. The human immune system is a complex interactive structure that provides a defence against infection. By establishing that immediate physiological changes take place inside the body during a stressful period, we can look closely at the effects of these changes and try to establish whether stress also helps instigates other changes within the body.
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Heart rate, blood pressure, breathing and energy levels increase, preparing us for fight or flight. The body is tense and ready to deal with the threat. The second stage is the resistance stage, if the stressor persists then our body must adapt and maintain a more stable and long-term level of arousal and coping. Our body seems to be adapting to the effects of the stressor at hand.
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This approach makes sense because it is a well-known fact that any colour-hue can be produced by mixing together any three primary colours to the appropriate degrees, so why not use the same principle for perception of colour? Physiological evidence for the Trichromatic theory is provided by Dartnall et Al (1983), who made use of microspectrophotometry - where a tiny spot of light is shone onto a single cone in the eye and the amount of light absorbed is measured at different wavelengths.
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The Behaviourist Approach explains that all behaviour is learned therefore mental disorders are learned. The process in which behaviour is learned is known as conditioning. There are two main processes of conditioning which are known as classical conditioning and operant conditioning. Classical conditioning involves learning an association between two stimuli. Learning through association was first discovered by Pavlov (1903) with his study famously known as Pavlov's Dogs. During this study, Pavlov's Dogs were given a meat powder and had their saliva collected by a surgically implanted tube. A bell was used to make noise when the dogs were fed, over time Pavlov noticed that the dogs began salivating just by hearing the noise of the bell.
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He had to take tranquillisers in order to synchronise his cycle with the rest of the world. This suggests that light, an exogenous zeitgeber, is the dominant time cue. Siffre spent six months in a cave. He had artificial light and could ask for the lights to be put off when he wanted to sleep and put on when he woke up. His sleep-wake cycle extended to about 25 hours.
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These explanations can therefore be praised for taking a more holistic approach. However, a weakness of explanations of circadian rhythms is that they are often nomothetic. This means that they assume circadian rhythms are the same for everyone. For example, Siffre's research suggests a free-running sleep/wake cycle of 25 hours, but research since has shown some have a 24 hour cycle. This is problematic because it appears a more idiographic approach would be more suitable, and by being nomothetic the explanations may be too simplistic.
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This means that by focusing solely on biology (genetics), the theory ignores the role learning may play in aggression. For example, Bandura demonstrated children learned through Social Learning Theory to be aggressive towards a Bobo Doll after observing an adult being aggressive. This is a problem because it suggests that learning also plays a role in aggression, so a purely biological approach may be too narrow. Another weakness of the theory is that it is deterministic. This means that it assumes that every XYY male will be aggressive. For example, since this time, it has been shown that males with this gene aren't aggressive if they choose not to be (it should also be noted recent research shows that the gene isn't strongly linked to aggression).
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and this causes an abnormal behaviour like throwing your revision guide at someone. CBT believes that by changing these faulty cognitions to healthier ones the behaviour will change as a result. In stress this form of therapy can be broken down into two sections - hardiness training and stress inoculation therapy. There are three stages to SIT - Stage 1: Conceptualization - The therapist and client explore how the client views and copes with stress Stage 2: Skill acquisition & rehearsal - This can be broken down into two types: Direct action and Cognitive Coping.
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'Feeding Centre'. VMH inhibits eating when we're full and responds to an increase in Blood Glucose Levels (BGL) & decrease in ghrelin; the hormone released when stomach is empty. The LH does the opposite to VMH responding to decrease in BGL & increase in ghrelin. A malfunction in this part of the hypothalamus may offer a possible explanation of eating disorders. Although there is no specific evidence linking the VMH/LH to eating disorders there is evidence to support the dual-centre theory including research that found that damage to the LH may cause Aphagia- failure to eat when hungry.
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It is estimated that approximately 20% of shiftworkers report falling asleep during work. This is particularly worrying for people such as lorry drivers, who could crash their vehicle and kill themselves and/or others. Apart from the disasters that could occur on the outside, internal problems also occur. Workers on night shifts have significantly higher rates of heart disease and diseases of the digestive system. Perhaps knowledge of this is not widespread - and makes the issue of shitworking an ethical issue. Take workers in underdeveloped countries such as Taiwan. There is already criticism of the exploitation of workers for low wages, but awareness has not been raised of the possible health problems these people may be suffering as a result of shitwork, and the consequences of this - maybe they will die earlier.
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