Evaluation

• Strength - Lateralisation in the brain is connected. P: Even in connected brains, the two hemispheres process information differently. E: eg. Fink et al (1996) used PET scans to identify which brain areas were active. Participants with connected brains were asked to look at global elements of an image (surrounding areas eg. whole forest - where regions of the right hemisphere were more active). The left hemisphere was shown to dominate when focussing on finer details. This suggests hemispheric lateralisation is a feature of split and connected brains when concerning visual processing.
• Limitation - One brain. P: The idea of the left hemisphere as an analyser and the right hemisphere as a synthesiser may be incorrect. E: This means there may be different functions of the right hemisphere and left hemisphere but research suggests people do not have a dominant hemisphere which creates a different personality. E: Eg. Nielson et al (2013) analysed brain scans from 1000+ people aged 7-29 years and found people had dominant hemispheres for different tasks but there was no evidence found of a dominant side; ie. artisits or mathmaticians.
• EV EXTRA: Lateralisation vs. Plasticity - Is adaptive enabling two tasks to be performed simultaneously with greater efficiency. Rogers (2004) showed lateralised chickens could find food while watching for predators but normal chickens couldn't. But the idea of plasticity is seen as adaptive following damage so non-specialised areas take over some functions supports complex link between hemispheres and the value of sperry's work.