Core study 17- Sperry (B)

Question 1

What does lateralisation mean?

Answer 1

The theory that behavioural functions are controlled by specific regions of the brain

Question 2

Background

What is brain lateralisation?

Answer 2

The fact that our brains are split into two cerebral hemispheres:
* Right hemisphere- controls left side of body
* Left hemisphere- controls right side of our body

Question 3

Which hemisphere is language believed to be lateralised to?

Answer 3

The left hemisphere

Language is Lateralised to the Left

Question 4

Background

How did Paul Broca discover that the left frontal lobe is critical to successful speech production?

Answer 4

He carried out post-mortems on those that had severe speech production issues

He obsereved they had damage to the left frontal lobe

Question 5

Background

What does commissurotomy mean?

Answer 5

The procedure to split the corpus collosum

Question 6

Background

What is the corpus collosum?

Answer 6

The bridge which connects the two hemispheres together

Question 7

Background

Is vision lateralised or non-lateralised?

Answer 7

Non-lateralised- it involves both hemispheres

Question 8

Background

Where is information processed when shown to the Left visual field (LVF)?

Answer 8

Processed by the right hemisphere (RH)

Same vice versa: LVF~RH, RVF~LH

Question 9

Background

Where does information process when shown to the left visual field (LVF) in terms of hemisphere and hands?

Diagram in booklet and on mindmap

Answer 9

LVF~RHem~LHand

Question 10

Background

Where does information process when shown to the right visual field (LVF) in terms of hemisphere and hands?

Answer 10

RVF~LHem~RHand

Question 11

Aim

What did Sperry aim to investigate?

What did he want to see specifically?

Answer 11

To test hemisphere de-connection in humans

• If memory and perception differ between hemispheres
• Extent to which hemispheres would usually interact to achieve memory and perception successfully

Question 12

Method

What type of experiment was used and why?

Answer 12

Quasi experiment- participants already had a split brain or not

Question 13

Method

How did the study adopt laboratory elements?

Answer 13

It took place in laboratory conditions and had controls

Question 14

Method

What design was used?

Answer 14

Repeated measures

Question 15

Method

What was the IV?

Answer 15

Whether you had a split-brain vs whether you didn’t

Question 16

Method

What was the DV?

Answer 16

The ability to perform a variety of visual and tactile (physical) tests

Question 17

Sample

What did Sperry’s sample consist of?

How many, gender, age..?

Why was there no control group used?

Answer 17

11 epileptic patients who had undergone a commissurotomy

Mix of ages and genders

Previous research already informed how lateralisation works in average brains

Question 18

Procedure

What two things were used in both the visual and tactile tasks?

Both begin with a ‘T’

Answer 18

• Translucent screen- light can pass through but it isn’t clear
• Tachistoscope- projector

Question 19

Procedure

What were participants instructed to do firstly on the visual task?

Answer 19

Cover up one eye, then centre gaze on fixed point in middle of translucent screen

Question 20

Procedure

How were the visual stimuli arranged and how were these shown to participants?

Answer 20

• On 35mm transparencies in a standard projector
• Back projected at 1/10th of a second (too fast for eye movement to process info in wrong visual field)

Question 21

Procedure

How could the tactile task be carried out in terms of it’s setup?

Answer 21

There was a gap below the translucent screen- touch and feel objects, but not see

Question 22

Procedure

Where were the objects placed?

Answer 22

In either the participants’ right, left hand or both hands

Question 23

Results

When would information be recognised again (visual task)?

Answer 23

If information was shown to the same visual field as the first time

Question 24

Results

What was found about the info presented to the right visual field?

Answer 24

It could be described in speech and writing

Question 25

Results

What was found about the same info being presented to the left visual field?

NOTE: This info goes to the right hemisphere

Answer 25

Participant either did not see anything/ there was only a flash of light on the left side (couldn’t be described)

Question 26

Results

What was found about objects placed in the right hand?

Answer 26

These could be described in speech or writing

Question 27

Results

When would participants have to make wild guesses about what had been placed in their hands?

Answer 27

If the same object had been placed in their left hand- this goes to right hemisphere- so they were unaware they were holding anything

Question 28

Conclusions

Can it be confirmed that language is lateralised in the left hemisphere?

Answer 28

Yes

Question 29

Conclusion

What did Sperry conclude split-brain patients lacked?

Answer 29

Cross-integration (2nd hemisphere doesn’t know what 1st hemisphere has been doing)

Question 30

Conclusion

What did Sperry conclude about split-brain patients’ streams of consciousness?

Answer 30

They have 2 independent streams of consciousness- each with it’s own memories, perceptions and impulses

Question 31

GREEDUM

How can reliability be argued as a strength?

Answer 31

Participants had same information and objects presented to them in visual and tactile tasks

Question 32

GREEDUM

How can ethics be argued as a strength?

Answer 32

All 11 epileptic participants gave consent to take part in lab exp

Question 33

GREEDUM

How can generalisability be argued as a weakness?

Answer 33

11 epileptic patients- uncommon sample

Question 34

GREEDUM

How can data be argued as a weakness?

Answer 34

Qualitative data- info presented to LVF goes to right hemisphere- can’t be spoken