BIO-PSYCHOLOGY Flashcards
Hemispheric Lateralisation - strength 1
image on screen
Credible research shown by Sperrys pioneering split brain research. He projected an image into a patient’s right visual field (processed by left hemisphere) and an image into the left visual field (processed by right hemisphere). When shown to right visual field, pt could easily describe but not pick out/draw and when shown to left, pt could not describe n reported nothing was there. Sperry round that the left hemisphere is more geared towards analytic and verbal terms whereas our right half is more adapted to spatial tasks n music. This suggests two hemispheres do have separate functions, left = analyser, right == synthesiser.
Hemispheric Lateralisation - weakness 1
type of research/evidence
Case study evidence. Wernicke and Broca’s area studies have involved individuals and investigate the effect of damage to their brain on their cognitive functions. But these effects may be specific to the individuals concerned and may not be extrapolated to others. This is particularly true as the lateralisation of language areas to the right hemisphere is not universal. Meaning this theory cannot be generalized and therefore less accurate to real life.
Hemispheric Lateralisation - strength 2
type of data
Sperrys procedure used a mix of quasi experiments and clinical case studies, he was able to combine quantitative and qualitative approaches. The quasi experiment gave numerical results which could be easily analysed statistically. The case study gave qualitative, descriptive data which meant it was very in depth. A combination of methods allows for a collection of statistically reliable information about research participants.
Hemispheric Lateralisation - weakness 2
type of brain study
Post - mortem studies are frequently used when examining Wernicke and Broca’s area - these investigate the brain after death. Although this may help to pinpoint areas of the brain involved in different functions, it’s not possible to then refine the understanding of these functions by getting the p’s to do further tasks. Meaning that modern methods of brain imaging on live patients may reveal more accurate information. Therefore, this theory lacks validity as not all research can give an accurate/ in depth understanding.
Split brain research - strength 1
language
Useful practical applications enabling a greater understanding of the differing functions of the hemispheres and adding to the unity of the consciousness debate. For instance, we now know that language is largely processed in the left hemisphere and so we can distinguish language/ processing difficulties sooner. This allows our scientific understanding of the brain to move forward from split brain research.
Split brain research - weakness 1
no. of participants
The split brain research lacks generalizability as there was a limited number of participants (only 10-15 have been subjected to systematic study). In addition, the P’s varied considerably in age, gender and handedness as well as the age they developed epilepsy and the degree of drug therapy they had experienced before their operation
These are all extraneous factors that will affect their behaviour. This implies split brain research is likely to be affected by multiple variables and as such lacks representativeness to target population and generalisability.
Split brain research - weakness 2
epilepsy
Establishing cause and effect - The split brain patients were often compared to neurotypical controls, but these people often had no history of epilepsy (i.e not matched pairs) and therefore this could be a potential confounding variable as a history of epilepsy could affect general behaviour. This means it’s harder to establish cause and effect and there could be other explanations for split brain findings, such as response to drug therapy, experience of epilepsy, etc.
Split brain research - strength 2
image on screen
Sperry made use of highly specialised and standardised procedures. His method of presenting visual information to one hemispheric field at a time was smart. Typically, p’s would be asked to stare at a given point, the image would be flashed up for 1/10th of a second, meaning the split brain patient wouldnt have enough time to move their eyes across both sides of the visual field. This allowed Sperry to vary aspects of the basic procedure and ensured that only one hemisphere was receiving information at a time. Thus he developed a very useful and well controlled procedure which is highly reliable.
Functional recovery of the brain after trauma - strength 1
tumour
Research to support. Danelli investigated a case of a boy who had most of his left hemisphere removed aged 2 and a ½ in order to remove a tumour. With intensive therapy, his right hemisphere was able to take over almost all of the functioning (language, speech, etc). This study implies our brain can undergo neural reorganisation in order to recover and regain skills.
Functional recovery of the brain after trauma - weakness 1
type of research
Case study evidence. Danelis young child research lacks external validity. Not all individuals are the same so a case study on a young person especially, it may have meant he could undergo synaptogenesis for example, as he was still an infant. Case studies are also difficult to replicate. These factors make case studies unrepres and therefore lack population validity.
Functional recovery of the brain after trauma - weakness 2
soldiers
Recovery from brain trauma is not universal and there are a number of factors that may influence an individual’s ability to recover. One identified factor is age, with most research indicating that functional plasticity reduces with age. For example, Teubar (1975) found a negative correlation with age and recovery. He studied soldiers with brain damage and found 60% under 20 showed significant improvement, whereas only 20% over the age of 26 showed similar recovery. This demonstrates a positive correlation between age and functional recovery. This could mean that older patients need more intensive rehab following trauma.
Functional recovery AND brain plasticity - strength
stem cells
Research in this field will inevitably lead to very useful practical applications.
Newer research into the role of stem cells has revived interest in Neural Transplantation. In theory stem cells implanted in a damaged area have the potential to grow into neutrons and make functional synaptic connections that would help restore behavioural functions. Tajiri et al (2013) has shown the potential of this with rats with traumatic brain injuries.
This research is in its early days so there is a long way to go yet, but it is an exciting psychological avenue to explore.
Brain plasticity - strength
taxi drivers
London taxi driver research. Maguire et al’s research supported the idea of brain plasticity as
the results provide evidence for structural differences between the hippocampi of London taxi drivers and control participants, therefore suggesting that extensive practice with spatial navigation affects the hippocampus.
biological rhythms: endogenous pacemakers - strength 1
cave
Case study evidence to support the role of endogenous pacemakers in regulating circadian rhythms like the sleep/ wake cycle. When Siffre spent several months underground in a cave in Texas and was not exposed to any EZ’s his circadian rhythm stretched to 25-30 hours. This shows that if we allow ourselves to “free run” our circadian rhythms extend (typically to 25 hours).
This supports the idea that EP’s are important in regulating this rhythm, but also suggest that external factors play a role too. (E.g bodily rhythm) exogenous zeitgebers.
biological rhythms: endogenous pacemakers - strength 2
hamsters
scientific evidence to support the role of endogenous pacemakers in regulating circadian rhythms like the sleep wake cycle from animal studies. For example, Ralph et al (1990) removed the SCN’s from “mutant” hamsters who had circadian rhythms that had mutated to 20 hours. He transplanted these SCN’s into the brains of hamsters with normal circadian rhythms and found their rhythms changed to those of mutant hamsters. This suggests that EP’s (and the SCN in particular) play a major role in the regulation of circadian rhythms.
