Biology - Sperry Flashcards
Aim
Investigate effects of hemisphere de connection and the functions of two hemispheres
Participant
11 pots
One male had 51/2 years before
1 female in 30s had 4 years ago
9 others had at varying times but not long before Study
Visual test procedure
Sat in front of projector screen focused on fixation point in the middle of the screen
Visual stimuli would appear fro 1/10 of a second
Stimuli either presented either to one visual field or both
Tactile test procedure
Below the screen was a gap where a grab bag had been placed
Different tests were used e.g an object to either left or right hand and would have to identify objects
Visual tests results
2 separate memories - if stimuli was dhown to one visual field wouldn’t be recognised again until show till same vf
Matching pictures - if image presented to lvf would point to matching picture or object with their left hand even though said they didn’t see anything
Nude pin up - would laugh and giggle but wouldn’t be able to say why
Stimuli presented to both vf
? And $ ? Shown to lvf rvf $
Composite words key to lvf and case to rvf would say case but would pick out key
Conclusions
Two independent hemispheres each with consciousness and no transfer of info between both of them with hemisphere deconnection left associated with language
Right with emotion
Research method
Quasi - I’ve naturally occurring . Participants didn’t have hemisphere deconnection for study had it before to stop epilepsy , controls - able to show brain lateralisation and work out functions of both hemispheres e.g stimuli was presented for 1/10 of a second participants not able to talk unless talked to
Enabled them to suggest why participant couldn’t perform task
Types of data
Qualitatively
Describing what participants could and couldn’t do in both visual test and tactile test - rich data shows a pattern of difficulties enabling sorry to Map out brain lateralisation
Quantitate could have given a clear scientific analysis of the findings
Ethical considerAtions
Study conducted ethically consented study no deception, neither harmed or Stressed when carrying out test
Validity
Extremely small sample
Whether abnormal brain can be generalised to normal brain . It may be experiences prior to surgery that made their brains different from Normal brains anyway caused by epilepsy . Not everyone has gone under a major surgery.
If individual differences in brain lateralisation in a sample so small imagine individual differences in general population
Ecological validity
Unlikely be reproduced in real life situations, those with severed corpus collusum would have both eyes open received by hemisphere at same time doesn’t matter if they have a severed corpus collusum lacks ecological validity.
Tactile tests more ecological valid if we root around for something in pocket we are feeling things with one hand without being able to see
Reliability
Found general trends in lateralisation of brain function and similarities up in the split brain participants reliable.
Sample
Small whether abnormal brain can be generalised to normal brain
Ethnocentrism
Not ethnocentric - brain lateralisation is affected by anatomy and physionogmy of our brain .
Individual differences - environment and culture affect how our brain develops only affected by western environment can’t be the same in different country
Links to area and perspectives
Investigating the regions of the brain and lateralisation. Of brain function . Demonstrated importance of corpus collusum as a communication pathway between left and right hemisphere
