Sperry Flashcards
What was the aim of Sperry’s study?
To investigate the effects of hemisphere disconnection in split-brain patients and how each hemisphere functions independently.
What is meant by a split-brain patient?
A person who has had their corpus callosum severed, preventing communication between the left and right hemispheres of the brain.
Why did the participants undergo split-brain surgery?
To treat severe epilepsy that could not be controlled with medication.
What did Sperry’s study demonstrate about lateralization of brain function?
That the left hemisphere is specialized for language and the right hemisphere is specialized for spatial and visual tasks.
What research method did Sperry use?
A quasi-experiment (since the participants already had split-brain surgery, making them a naturally occurring group).
How many participants took part in Sperry’s study?
11 split-brain patients, all of whom had undergone corpus callosotomy due to severe epilepsy.
11 split-brain patients, all of whom had undergone corpus callosotomy due to severe epilepsy.
Because split-brain patients are rare, making it difficult to obtain a large sample.
How was visual information presented to each hemisphere in Sperry’s study?
By flashing an image or word to either the right visual field (processed by the left hemisphere) or the left visual field (processed by the right hemisphere).
What happened when an image was shown to the right visual field (left hemisphere)?
The participant could name the object because the left hemisphere controls language.
What happened when an image was shown to the left visual field (right hemisphere)?
The participant could not verbally name the object but could draw or select it using their left hand.
Why couldn’t participants verbally name objects shown to the left visual field?
Because the right hemisphere lacks language abilities, and the corpus callosum was severed, preventing the information from transferring to the left hemisphere.
How was tactile information tested in Sperry’s study?
Participants held objects in either their left hand (right hemisphere) or right hand (left hemisphere) without seeing them.
What happened when an object was placed in the right hand (left hemisphere)?
Participants could name the object and describe what they were holding.
What happened when an object was placed in the left hand (right hemisphere)?
Participants could not name the object but could select it from a group of objects using their left hand.
What does the tactile experiment show about hemispheric specialization?
The left hemisphere is responsible for speech production, while the right hemisphere is better at non-verbal recognition.
What did Sperry’s study reveal about split-brain patients?
Each hemisphere can function independently, but without the corpus callosum, they cannot communicate with each other.
What role does the left hemisphere play according to Sperry?
It is dominant for language, speech, and analytical thinking.
What role does the right hemisphere play according to Sperry?
It is dominant for spatial awareness, face recognition, and creative tasks.
What is the overall conclusion of Sperry’s study?
The two hemispheres of the brain have specialized functions and, in split-brain patients, they act independently without communication.
Why does Sperry’s study have high internal validity?
The controlled laboratory conditions and precise visual & tactile tasks ensured accurate results.
Why does Sperry’s study have scientific credibility?
It used objective methods (e.g., presenting stimuli for 0.1 seconds) to test hemispheric functions systematically.
What is a real-world application of Sperry’s findings?
It helps understand how brain damage (e.g., strokes or tumors) affects language and perception, aiding rehabilitation strategies.
Why does Sperry’s study lack generalizability?
The sample size was only 11 participants, all of whom had epilepsy, meaning the findings may not apply to non-epileptic individuals.
Why does the study lack ecological validity?
The tasks were highly artificial (e.g., flashing images for 0.1 seconds), which does not reflect real-world experiences.
Why is it difficult to determine the long-term effects of split-brain surgery from Sperry’s study?
The study only tested participants at a single point in time, meaning we don’t know how the brain adapts over time.
What was the first step in the procedure of Sperry’s study?
Participants sat in front of a tachistoscope (a screen that presents images for a very brief time) and were instructed to focus on a central fixation point.
How were visual stimuli presented to participants?
Images or words were flashed for 0.1 seconds (too fast for eye movement) to either the right visual field (left hemisphere) or the left visual field (right hemisphere).
How did Sperry test tactile (touch) responses?
Participants placed their hands under a screen where objects were placed in either their right hand (left hemisphere) or left hand (right hemisphere).
How did Sperry ensure the reliability of his results?
He repeated each trial multiple times and used different stimuli to confirm consistent patterns in hemispheric function.
