Lateralisation of Function Flashcards
What is Hemispheric lateralistaion?
The theory that the two halves of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.
What is the corpus callosotomy?
The left hemisphere and the right hemisphere of the brain are connected by a bunch of nerve fibres called the corpus callosotomy. A corpus callostomy severves these connections.
What research has been done to support the theory of lateralisation?
In the 1960s, research on the function of each hemisphere had to be done with people in with a servered corpus callosotomy. This is because the left and right hemisphere of the brain are seperated so the two hemisphere of the brain cannot communicate with eachother. This means psychologists can investigate what specfific brain functions occur in different hemispheres of the brain.
Why might people have their corpus callosum severed?
People with servere espilsey may have a had there corpus callosum is severed in brain surgery if they are resist to medications for their epilesy to reduce the chance of a Grand Mal seizures. They can overload the entire brain, which could lead to death. This is surgery is usually not done today.
Name an example of a study for lateralisation of function
Sperry (1968)
Outline the Sperry 1968 experiment into lateralisation of function
11 split brain patients and 11 patients with their corpus callosum intact.
Different activites were tried with partcipants including touch of objects and visual presentation of stimuli to see how different side of the brain performed tasks. They were asked to use different sides of their body to investigate how well different hemisphere of the brain functions. After exposure to different stimuli to each hemisphere of the partcipants had to say or draw what they saw or touched.
What results came out of the Sperry experiment?
The left visual felid will pick up the image of the object. This will be sent the right hemisphere of the brain. The left hemisphere of the brain deals with lanuage so when the patient is asked to name the object they will not be able to. However when the patient is asked to use the sense of touch to identify the image with an object with their left hand they will be able to because the right side of the brain has identified with it and can deal with the sense of touch.
Then this is repeated when the image is presented on the right side of the focus point in the right visual felid the image will be sent to the least side of the brain and the lanuauge to verbalise that they saw will be able to be created. However then they are asked to touch with their right hand it will go to the left hemisphere (the right hemisphere is stronger at this than the left) of the brain which this the hemisphere that the information is stored and therfore sometimes they will able to identify the object through touch. (occasinaly they can but in most cases they cannot.
What functions are the left hemisphere of the brain supposedly associated with?
- Produces speech
- Dominate for processing lanuage
- Logic and problem solving
What functions are the right hemisphere of the brain supposedly associated with?
- Spatial awareness
- Tactial recognition
- Drawing ablities
- Facial recognition
Strengths of the theory of lateralisation of function
- Scientific method- controlled conditions
- Had a control group
- Findings have been confirmed by later research (Micheal Gazzaginer and modern brain scan research found that lanuage is lateralised on the left for right handed people). In left handed people lanuage is more likely to be bilateral.
- Right- holostic processing- emotional content of lanuage
- Left- tasks that require analysis and understanding
- Affirm the validity if sperry’s orginal findings
Weakness of the theory of lateralisation of function
- Did not get the same results from split-brain patients every time
- Small sample group of Sperry’s original research- had to genralise 11 peoples finding univerially
- Eplisey patients don’t have the same brain stucture and function as a normal brain because seizures change the stucture so perhaps cannot be generalised to everyone.
- Unbalanced- The control group were not epileptic
- Beta bias- all partcipants are males
- Sperry’s patients were all right-handed
- Some had their corpus callosum entirely cut though and some have some remianing parts intact.
