Sperry's study

Question 1

What does contralateral mean?

Answer 1

Each hemisphere in our brain controls the opposite side of our body.

Question 2

What is lateralisation of function?

Answer 2

The speciality of each area of the brain

Question 3

What is the corpus collosum?

Answer 3

A bundle of fibres that connects the two hemispheres of the brain

Question 4

What is a commissurotomy?

Answer 4

The operation which severed the corpus collosum

Question 5

What was the aim of Sperry’s study?

Answer 5

To study the effects of brain hemisphere disconnection and the functions of the separated hemispheres

Question 6

What type of experiment is Sperry’s study and What is the evidence?

Answer 6

A Quasi experiment
The main IV was whether the participants had a split-brain or not. This was already done and having the surgery had nothing to do with Sperry.

Question 7

what is the background to Sperry’s study?

Answer 7

The language abilities of the left hemisphere were just identified in the 19th century by Broca and Wernicke. They each studied patients with brain damage to key areas of the brain and found it led to deficits in language.

Question 8

What are Broca and Wernicke’s areas for?

Answer 8

Broca’s area is responsible for speech production

Wernicke’s area is responsible for speech comprehension.

Question 9

What was the sample of Sperry’s study?

Answer 9

Used 11 patients who had severe epilepsy and who had previously undergone a commissurotomy (compared against those who had not had surgery - control group

Question 10

What were the weaknesses of Sperry’s study?

Answer 10

There was a small number and had limited generalisability because it was only people with epilepsy

Question 11

What was the equipment used in Sperry’s study?

Answer 11

Tachistoscope
back projector
objects

Question 12

What was the visual part of Sperry’s study?

Answer 12

The participants were asked to fix their eyes of a fixation point in the middle of a screen. A stimulus was projected on either the left or right side of the middle of the screen for less than 1/10 of a second.

Question 13

What was the tactile part of Sperry’s study?

Answer 13

Two different objects were placed in each hand, then hidden for retrieval amongst a pile of objects.

Question 14

What are two examples of stimuli shown to participants in Sperry’s study?

Answer 14

Hammer

Ball

Question 15

What were the conclusions of Sperry’s study?

Answer 15

One half of the brain does not know what the other half is doing
The left hemisphere is responsible for language, especially speech and writing - It can communicate from the right visual field or the right side of the body.
The right hemisphere can’t speak/write - can show non-verbally that mental processes from left visual field and left side of the body are present.
Therefore a useful application of this knowledge would be the medical profession who can help patients with similar disorders.

Question 16

How good is Sperry’s study ethically?

Answer 16

No ethical guidelines were broken - participants fully consented.

Question 17

Did Sperry’s study have internal reliability?

Answer 17

Yes, it was very standardised and had lots of controls.

Question 18

Did Sperry’s study have external reliability?

Answer 18

They did show a consistent effect but there weren’t really enough participants (only 11) and they had individual medical differences

Question 19

Did Sperry’s study have internal (construct) validity?

Answer 19

no because We don’t know why they were laughing and giggling about the naked woman
but yes because the findings did show lateralisation of function

Question 20

Did Sperry’s study have external (population) validity?

Answer 20

It isn’t generalisable as there was a very small sample size and the participants had experienced different levels of commissurotomy so doesn’t represent people with epilepsy that haven’t had the surgery.

Question 21

Did Sperry’s study have external (ecological) validity?

Answer 21

The visual task: not really - findings would not be found in regular life as stimuli are not selectively directed towards a single hemisphere
The tactile task: Yes as holding something in only one hand is likely to happen in real life.

Question 22

When objects are presented to the right visual field, where does the information go?

Answer 22

Left hemisphere

Question 23

What could the participant do in Sperry’s study when objects were presented in the left visual field?

Answer 23

They could point to a matching object or draw the objects, despite insisting that they couldn’t see anything.

Question 24

What could the participant do in Sperry’s study when objects were presented in the right visual field?

Answer 24

Participants described it in a speech and written format.

Question 25

What happened when participants in Sperry's study were presented with a nude pin up to the left visual field?

Answer 25

The would giggle/ look embarrassed but could not say why and this suggests that the right hemisphere is its own conscious entity.

Question 26

What could the participant do in Sperry's study when objects were felt by the right hand only?

Answer 26

They described the object by name in speech and in writing

Question 27

What could the participant do in Sperry's study when objects were felt by the left hand only?

Answer 27

They could feel it with their left hand - by touch and in a bag of objects. When the objects were placed in one hand, they could point to where the object was with the same hand that held the object.

Question 28

Was Sperry's study ethnocentric?

Answer 28

Since brain lateralisation is affected by anatomy and physiognomy of our brain, it wasn't ethnocentric as it investigated species specific behaviour. However, Sperry notes that there were individual differences between participant and our brain development is influenced by our environment and culture so it might be that people not brought up in a western culture may have reacted differentlt.

Question 29

How does Sperry's study link to the psychology as a science debate?

Answer 29

It is replicable - testable (falsifiable) and is objective as pretty much everything was factual

Question 30

How does Sperry's study link to the reductionism vs holism debate?

Answer 30

It was very reductionist as it only looked at the brain/biology, not any other explanations.

Question 31

How does Sperry's study link to the free-will/ determinism debate?

Answer 31

Mainly determinism as it was biological determini9sm - dictated by the brain structure got the surgery of their own free will

Question 32

How does Sperry's study link to the socially sensitive research debate?

Answer 32

It could result in stigmas or discrimination towards people who had undergone this surgery.

Question 33

How does Sperry's study link to the individual/situational debate?

Answer 33

Their brain structure was specific to them so was individual, however the equipment to analyse this was a very specific situation, so could have influenced their behaviour