Hemispheric disconnection and unity in conscious awareness - Sperry 1968. Evaluation In 1968 the neuropsychologist conducted a study into split brain patients while working at the California Institute of Technology. Previously he had carried out research similar to this, in the1950s, splitting the brains of cats and monkeys. It was during this research that he realise3d that you could teach one of the hemispheres a task, while keeping the other hemisphere unaware of the information learned. This discovery supported the idea that the brain consisted of two independent pieces as opposed to one unified brain. The importance of this work was appreciated when he won a Nobel Prize in 1981. This study was performed to further this research that he had carried out, this time, on humans. The brain splitting operation was not simply done for the study, as this would have been unethical, participants had had their brains split un an attempt to stop epileptic fits in epileptics. The operation used on the epileptics was called a commisurotomy, where all the bundles of nerves connecting the two halves (hemispheres) of the brain are cut, even the less major ones. Sperry's aim with this study was to investigate the effects of isolating the two hemispheres from each other, and to show that the hemispheres have different functions. Sperry wanted to map lateralisation of the brain and show that information in one side of the brain is not available to the other side. This study comes under the Physiological approach (or the Bio-Psychological approach). This approach uses biology and psychology to explain various behaviours. It involves studying the nerves and chemicals in the body, especially the brain. The physiological approach's development is closely linked to the development of new technologies for observing and measuring the body. Although it isn't really a school of psychology as such, it has a strong tendency towards the reductionist approach, 'Reducing' behaviour to its neuronal and biochemical elements. Looking at behaviour at its 'root'. The design of the study was a quasi - experimental design which compared split brain subjects with the normal subjects, and compared case studies of all the individual patient participants. This is a laboratory experiment. One advantage of this quasi - experimental design is that there is less chance for the experimenter to interfere with the variables, considering that the independent variable is 'naturally occurring' so to speak. This lack of interference increases the reliability of the results obtained, and also the validity of the study. An advantage of the Bio-Psychological approach is that there is very little room for interpretation of the results as you are studying behaviours at their core, as opposed to having to infer the reason for the behaviour. A disadvantage of the methodology of this study is that it is a lab experiment, meaning that it lacks in ecological validity, as many of the tests carried out on the participants would not occur in real life. A further disadvantage of this design is that it allows for demand characteristics, in that the participants may realise the aims and purposes of the study and thus intentionally produce desirable results, or perhaps undesirable results. The participants in this study where a group of patients who suffered from severe epilepsy, which couldn't be controlled by medication. The participants had undergone a commisurotomy, a possible remedy to epilepsy. The sample was a self-selecting sample, due to the rarity of people who had undergone the commisurotomy. Two of the participants had undergone the surgery some time before the study; the other 9 had only recently A representation of the apparatus used. A representation of the apparatus used.
undergone the operation.
This study used equipment that allowed the participants to have various sensory stimuli presented to either hemisphere of the brain in various combinations....