| What are the main functions of the left and right hemisphere of the brain? | - The lefts role is language, reasoning and logical thought
- The right hemispheres function is creativity, imagination and spatial awareness |
| Background | - Vogal and Bogen
- Performed the split of the corpus callosum on people with epilepsy
- Did not cure epilepsy
- Sperry wanted to find out what the patients could and could not do |
| What hemispheres of the brain control each hand? | - The right hemisphere controls of the left hand, while the right hemisphere controls the right hand |
| What was the aim of Sperry's research? | - To show the independent streams of conscious awareness possessed by each hemisphere and to show how each hemisphere has its own memories |
| What was the research method used in research by Sperry? | - A quasi experiment
- Could be seen as case studies, extensive tests on few ppts |
| Strengths and weaknesses of case studies | - Strengths: Allow in depth background information, carried out for rare cases where large samples are not available
- Weaknesses: Not necessarily generalisable, not always scientific |
| Materials | - Visual stimuli, computer, nude picture, geometric shapes... |
| What was the IV in research by Sperry? | - Having a split brain or not
- Control group not needed as the results of the tasks for people without split corpus callosums were already known |
| What was the DV in research by Sperry? | - The participant’s ability to perform a variety of visual and tactile tests |
| What was the sample Sperry used? | -11 patients, severed Corpus Colosseum for treatment of epilepsy
- There operations took place at a range of times from the earliest being 5 and a half years ago |
| What were the key tests conducted? | - Visual test
- Tactile test |
| What was the visual test used? | - Ppt (with one covered eye) looked at centre of a screen
- Visual stimulus appeared on the screen, 1/10 of a second, to fast to get the eyes in the wrong visual field
- Everything projected to the left of the screen is passed via
the left visual field (LVF) to the right hemisphere and vice versa |
| What was the tactile test used? | - Obejcts placed in ppts left or right hand, could not see them
- Information about the objects placed in the left hand is processed by the right hemisphere and vice versa |
| What were the key findings from the visual test? | - Info from RVF could be described in speech
- If the same info was presented to the LVF the participant said they did not see anything
- But could point to obejct with left hand
- $ sign to the LVF and ? to the RVF, the participant could draw the $ sign with his left hand but reported that he had seen a ? |
| What were the results for the tactile tests? | - Object in right hand described in speech or writing
-Object in left hand, seemed unaware they were holding anything
- 2 objects placed in both hands, hidden in a pile of objects, both hands selected their own object |
| 2 controls and why they are used | - Time images appeared on the screen
- Same images, some images could trigger the other side of the brain
- Same tasks |
| What are the main conclusions from Sperry's research? | - People with split brains have 2 separate visual processors
- They have lack of cross-integration
- They seem to have two independent streams of consciousness, each with its own memories |
| Evaluate the research method used by Sperry | - Highly controlled experimental design
- Quasi exp. , drugs may have affected results |
| Strengths and weaknesses of the research method | - Strengths: Ethical, could investigate variables that aren’t normally investigated
- Weaknesses: No control groups, small sample, couldn’t compare to a normal human brain, less control of extraneous variables |
| Evaluate the data collected by Sperry | - Qualitative data, descriptions of pts actions, rich, detailed but subjective
- Quantitative data |
| Strengths and weaknesses of the data collected | - Strengths: both types of data, analyse easily, compare, could see experiences of the participants
- Weaknesses: not a lot of qualitative data, could have guessed answers |
| What are the possible ethical considerations in this research? | - Mostly ethical
- Being shown the nude picture, could be uncomfortable
- Ethical surgical issues, there are many ways split brain patients could be emotionally affected |
| Assess to what extent Sperry's research can be seen as valid | - Small sample, can abnormal behaviour shown is generalisable to a normal brain?
- Differences in their brain may be caused by epilepsy or the medication they take |
| Assess to what extent Sperry's research can be seen as ecologically valid | - In real life spli brain person would use both sides of their hemispheres
- High eco valid, served corpus callosum part of their real life
- Low Ecol valid, artificially separate the visual and tactile info, ARTIFICIAL SETTING |
| Evaluate the sample used in Sperry's research | - Small sample
- Have to question whether abnormal behaviour can be generalised to a normal brain |
| Discuss the extent to which research by Sperry can be seen as ethnocentric | - Brain lateralisation is determinded by the physiognomy of our brain
- Not ethnocentric as it is species specific behaviour
- However our environment and culture affect brain development |
| To what extent does research by Sperry support psychology as a science? | - Controlled lab experiment which fulfilled scientific criteria of control, evidence and replication
- It is falsifiable |
| To what extent does research by Sperry be considered useful? | - Sperry's work allowed a greater understanding of the physiognomy of the brain
- It revealed the importance of the Corpus Callosum |
| Discuss relation by Sperry in relation to the free will vs determinism debate | - Biological determinism, the functions of the brain are fixed |
| How does reserach by Sperry link to the biological area? | - Investigates regions of the brain + lateralisation of brain function |
| How does research by Sperry link to the key theme? | - Regions of the brain
- Importance of the Corpus Callosum as a communication pathway between the hemispheres
- Outline the functions of the left and right hemispheres |
