Hemispheric lateralisation and split-brain research

-The way different hemispheres of the brain have different functions -e.g. Right hemisphere controls left side of the body and vice versa

-The idea that the two halves of the brain are functionally different -certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.

• it is when the RH is responsible for the left side of the body and vice versa -e.g this happens in the motor area- right side controlled by LH -vision is contralateralised and ipsilateral (opposite and same-sided)

• The RVF of both eyes are connected to LH , and LVF of both eyes are connected to RH

-S: Research support for lateralisation connected brains: Gereon Fink et al. (1996) used PET scans and showed when people were looking at wider details of pictures RH was more active and LH more active in finer details -L: One brain: idea that RH is synthesiser and LH is analyser may be wrong as the idea that people have a dominant side of the brain which creates a different personality. Jared Nielsen (2013) analysed brain scans from over 1000 people aged 7-29 and found people use different hemispheres for different tasks but there was no evidence of a dominant hemisphere- no artists brain or mathematics brain

-11 people who had a split brain( because of removing corpus callosum to reduce epilepsy) -they were studied in a set up where images could be projected to LVF (RH) and the same or different image projected to RVF (LH) -In a “normal brain” the corpus callosum would instantly communicate what it saw but this is not applicable in split-brain people

-If an image was shown to RVF the person could describe what they see but if it was shown to the LVF they said ‘there was nothing there’ - while the person could not describe it they were able to select a similar object using their left hand (RH) and would produce a emotional response to images (e.g. giggling)

-shows how some brain functions are lateralised -LH is verbal -RH is silent but is emotional

-S: Research support: Michael Gazzaniga (luck et al. 1989)found that split-brain participants perform better than normal brain people in tasks such as identifying the odd one out in an array of similar objects. Kingstone et al . (1995) the LH’s cognitve abilities are watered down by RH -L: Generalisable issues: None of the control group of neurotypical people had epilepsy which is a massive confounding variable as the differences between the 2 groups could have been because of epilepsy.