Component 2: Sperry (Biological) Flashcards
What are the concepts and principles of the biological area?
- Behaviour is influenced by biological systems such as brain functions, biochemicals or genetics.
- Any behaviour that is due to psychological factors must first be physical in nature.
What is visual field?
Areas of vision to the left and right of the central fixation point. Images in the left visual field are sendt to the right brain hemisphere, while images in the righ visual field are sent to the left hemisphere.
What is the corpus callosum?
A bundle of nerve fibres which transfer between the left hemisphere and the right hemisphere of the brain.
What is a commissurotomy?
It is a surgical procedure that burns/severs the corpus callosum.
What is functional lateralisation?
Each hemisphere has a different set of functions.
What is the function of the right hemisphere?
Processes pictures, object recognition, drawing and spatial awareness
What is the function of the left hemisphere?
Words, ability to speak and to recognise and undersatnd words and language.
What does controlateral mean?
Control. E.g the left hemisphere controls the right side of the body and vivce versa.
What is the background to Sperry’s study?
Sperry believes that the studies involving split-brain patients reveal the ‘true’ nature of the two brain hemispheres because a commissurotomy disconnects them from eachother, meaning they work independantly.
What was the aim of Sperry’s study?
To investigate the extent to which each hemishere of the brain functions independantly from eachother.
What was the research method used in Sperry’s split-brain study?
It was a quasi experiment as the IV was naturally occuring and cannot be directly manipulated.
No control group was required as the function of non-split-brain patients’ brains was already known.
What was the IV and DV in Sperry’s study?
IV - split-brain patients
DV - participants ability to perform in a variety of visual and tactile tasks.
Describe the sample in Sperry’s study.
It was a case study with 11 participants. 2 of them were studied in greater detail as they has had their operation severl years prior to the study.
Describe the procedure of Sperry’s study with split-brain patients.
- Sperry did not carry out the commissurotomy on the patients. This was done prior to the study.
- The equipment used was called a tachistascope
- The participant, with one eye covered, focused on a central fixation point in the centre of a screen.
- Visual stimuli (either words or images) was presented to either the left or right visual field for a tenth of a second.
- For the tactile task, particpants would place their hands under a screen and objects would be passed to either their left or right hand.
- Information about objects in their left hand was processed by the right hemisphere and vice versa.
What were the results of Sperry’s split-brain study?
Visual taks:
1. Information shown and rsponded to one visual field could only be recognised again if shown to the same visual field.
2. Information presented to the RVF could be described in speech or writing (with the left hand) . If the same visual stimuli was presented to the LVF, the participant would insist they had not seen anything.
Tactile task:
1. Objects placed in the right hand (LH) could be described in speech or writing (with the right hand) but if it was placed in the other hand, participants eitehr didn’t realise they were holding anything or they would make wild, innacurate guesses.
2. Objects felt with one hand could only be recognised by the same hand again.
