Zusammenfassung der Ressource
Sperry (1968)
- Key Terms
- Corpus Callosum
- The bundle of nerve fibres that
connects the two hemisphere of the
brain
- Quasi-experiment
- The IV in the experiment is not
manipulated, it varies naturally
- Aim
- Attempts to study the functions of separated and
independent hemispheres
- Procedure
- 11 ps who had already has surgery
on their corpus callosum
- Sperry did not conduct
the surgery, and the
surgery was not for the
purpose of the study
- Special apparatus that allowed
info. to be presented to one
hemisphere was used
- Ps vision is divided into left and right
visual feilds
- Their hands were hidden
from their vision
- One eye was
covered
- They centered their
gaze on a designated
fixation point
- Words or images
were flashed onto a
screen for 1/10 of a
second or less
- Info. from the
left visual field
goes to the right
hemisphere and
vice versa
- By flashing the image/word to
either the lef or right of the
fixation point the experimenter
determines which hemisphere
receives the info.
- For physical tasks the
objects were placed into the
ps hands on the other side
of a screen out of view
- The sensory info. is
received by only the
corresponding
hemisphere
- E.g. left hand goes to right
hemisphere
- The ps were
asked to find the
same object in a
grab bag with
either the same or
a different hand.
- Findings
- Ps act as if they have two
minds in one body
- If a piece of info is sent seen by
the left visual field and goes to
the right hemisphere, it is only
reconised again if it is seen by
the same visual feild
- Visual material shown
to the right visual field
sent to the left
hemisphere can be
described in speech
and writing
- If the same material is then shown to
LVF, the ps insists they do not see
anything. BUT, when asked to pick the
object within a group of objects they are
able to select the correct one
- If a different figure was flashed to each
hemisphere
- Eg. a $ to the
LVF and a ? to
the RVF
- The ps is asked to draw with their left
hand what they have seen, they will
draw they saw in the LVF ($)
- But if you asked them to tell
you what they saw they
would say the object from the
RVF (?)
- Objects in the right hand,
sent to the left hemisphere
can be described and named
- The right hemisphere
is able to:
- Select similar
items to a
target item
- E.g. a watch
rather than a clock
- Perform simple arithmetic operations
- Understand
both written and
spoken words
- Identify
objects
- Understand
fairly
complex
instructions
- Show appropriate
emotional reactions
- Strengths
- Quasi-experiment allows researchers to
investigate variables that are not able to
be investigated in a strict laboratory
experiment
- The techniques Sperry developed allowed the functions of the two hemispheres to
be studied which previously had been impossible
- Weaknesses
- The experiment was a quasi-experiment
- This does not give the experimenter complete control over the
independent variable