Zusammenfassung der Ressource
Sperry Case Study
- Background
- Language abilities of the left
hemisphere were first
identified in the 19th century
by Broca and Wernicke
- They studied patients with
brain damage to key areas
of the brain and found it led
to deficits in language
- Broca's area is
responsible for
speech production
- Wernicke's area is
responsible for speech
comprehension
- Key Terms
- Lateralisation
of Function
- One side of the
brain has a
different role
from the other
- Corpus Callosum
- Fibres that carry information
between the two hemisphere
- Split brain
surgery/Commissurotomy
- Surgical operation
to sever the corpus
callosum
- Aim
- To study the effects of
hemispheric
de-connection and the
functions of the
serperated
hemisphered
- Research Method
- Quasi Experiment
- IV was if P's had a
split-brain or not, this
was already occurring
and having the
surgery had nothing to
do with Sperry
- Sample
- 11 Participants who
had severe epilepsy
and who had
previously
undergone a
commisurotomy
- Small sample- Can't
be generalised
- To be able to compare
the 'abnormal' brain to
a 'normal' brain
- From America
- 2 P's had the
surgery some
time before
the sudy
- 9P's had the surgery recently
- Controls
- Fixation point
to look at
- Hands under a screen
and out of sight
- Back projected images to one side of
screen for only 1/10th of a second to
allow info to only enter one visual field
- Findings
- Objects
presented
in the RVF
- Info went to
the LH
- They Could:Say what was seen,identify by
pointing with their right hand and
find it amongst other objects
- The left hemisphere
has it's own memory
and language ability
- Objects
presented
in the LVF
- Info went
to the RH
- They could;Draw it,
identify by pointing
to it and find it by
using their left hand
- They Couldn't: Say
what they had seen
- The right hemisphere has
it's own memory, but does
not have language ability
- Different visual stimuli
were presented
simultaneously(Apple to
LVF and key to RVF),P
was asked to draw with
their left hand (out of
sight)what they had seen
- Apple info went to
the RH and Key
Info went to the LH
- They Could;
Draw apple with
left hand, say
they saw a key
- They Couldn't; Say they
saw the apple, they
couldn't explain why they
drew a key when shown
what they had drawn
- Simple math
problems were
presented to the LVF
- Info went
to the RH
- They Could; point to
the correct answer
with their left hand
- The RH has basic
mathematical
ability
- A nude pin-up
was presented
to the LVF
- Info went
to the RH
- They would
giggle and blush
- They Couldn't;
explain why
they were
giggling or
acting
embarassed
- The RH can
experience it's own
emotional reactions
- Objects were
felt by the
right hand only
- Info went
to the LH
- They Could; say
what it is and
find again with
their right hand
- The LH has
language ability in
relation to objects
that had been felt
- Objects were
felt by the left
hand only
- Info went
to the RH
- They Could; find
it again with
their left hand
- They Couldn't; name
the object or identify it
by the right hand from
amongst other objects
- The RH has a memory for
felt objects, it lacks language
ability. The two hemispheres
have their own memories
that the other hemisphere
cannot access
- Evaluation
- Ethics
- All Ethical
Guidelines
upheld
- No
deception,
harm
and
consent
obtained
- Reliability
- Internal
- Standardised
procedure with
high controls
- External
- Too small of a
sample to
generalise
- Found general trends
and consistency in
lateralisation of brain
function
- Validity
- Internal
- Subject variables
such as the severity
of past epilepsy
unknown- another
reason for the
behaviour
- External
- Population
- Too small of a
specific sample to be
generalised to the
whole population but
it there target
population
- Ecological (EV)
- Not realistic as we
compensate with
using both
eyes,hands and ears
- Ethnocentrism
- Not Ethnocentric- Investigating a
species and a specific behaiour
- Ethnocentric- Environment and cultural
influences affect how our brain develops
- Debates
- Psyc as a Science
- Controlled lab experiment,
that fulfilled the scientific
criteria-scientific discipline
- Able to be falsifiable,
replicable with a new
sample(may be hard to
obtain sample)
- Freewill-Determinism
- Determinism-Inability caused by the commissurotomy to not be able to
name objects that they touch with their left hands out of sight
- Usefulness
- Understanding the physiognomy of the brain, revealed
importance of corpus callosum-Intrinsically useful
- Relates to...
- Biological Area
- Investigating regions of the brain and
lateralisation of brain function shows
the importance of the corpus callosum
as a communication pathway between
the left and right hemisphere
- Key Theme-Regions of the Brain
- Sheds light and informs on the function of
the corpus callosum and how it is needed as
a communication pathway for information
- Shown by the spilt-brain P's who
couldn't perform some tasks unlike
'normal' control P's who could due to
having an intact corpus callosum