VISUAL ILLUSIONS STUDY - An investigation into illusory conjunctions and context-processing in

You are being invited to take part in a research study, which is looking at how the brain combines different features, such as colour or shape, into complete objects. The study aims to examine the instances where the brain combines the wrong features together to produce a visual illusion. This is quite common amongst people when they have not really concentrated on what they are looking at. For example if a blue car and a white van speed pass each other in the street, you might think you have seen a blue van and a white car instead. There is some evidence that these everyday visual illusions are less frequent in certain types of schizophrenia You have been asked to be a volunteer because you have been diagnosed with schizophrenia. There will be 59 other people like you that will be taking part in this study.

This study is being organised by University College London and is part of my research thesis. It will last for about one year. The South West Local Research Ethics Committee has approved this study.

You will be asked to look at a computer screen. A series of different coloured shapes will appear on the screen, on different sides, for a very brief time. You will be asked to say ‘yes’ if you have seen a red triangle. Each time you guess correctly you will be given 5 pence. If you guess them all correctly you will be given £5. The whole experiment will only take about 15 minutes to complete.

The task will not be harmful to you in any way and there will be no side effects from taking part. However I would like to reassure you that if I feel the tasks are too distressing for you I will withdraw you from the study straight away.

All information that is collected about you during the course of the research will be kept strictly confidential. Any information about you that leaves the hospital will be kept anonymous so that you cannot be recognised from it. You will be asked to sign a consent form to show that you agree to take part. You do not have to take part in the study if you do not want to. If you decide to take part you may

withdraw at any time without giving a reason. Your decision whether or not to take part will not affect your care and management in any way.

The study will be completed in June 2002 and the results will be available for anyone to look at in the Sub-Department of Clinical Psychology, University College London, 1-19 Torrington Place, London Wl.

Any queries about this study may be directed to myself, Tracey Brown at the above address. If you Avish, an independent person can provide you with more advice. Their name is, Hamish McLeod, Academic Unit, St Bernards Wing, Ealing Hospital.

VOLUNTEER INFORMATION SHEET

VISUAL ILLUSIONS STUDY

You are being invited to take part in a research study, which is looking at how the brain combines different features, such as colour or shape, into complete objects. The study aims to examine the instances where the brain combines the wrong features together to produce a visual illusion. This is quite common amongst people when they have not really concentrated on what they are looking at. For example if a blue car and a white van speed pass each other in the street, you might think you have seen a blue van and a white car instead. There is some evidence that these everyday visual illusions are less frequent in certain types of schizophrenia I will be testing 60 patients from a local hospital who have been diagnosed with schizophrenia. You have been asked to be a volunteer because I need to include 20 healthy controls to help verify the results

This study is being organised by University College London and is part of my research thesis. It will last for about one year. The South West Local Research Ethics Committee has approved this study.

The task will not be harmful to you in any way and there wiU be no side effects from taking part. However you may withdraw from the experiment at any time without giving a reason..

Any queries about this study may be directed to myself, Tracey Brown at the above address. If you wish, an independent person can provide you with more advice. Their name is, Hamish McLeod, Academic Unit, St Bernards Wing, Ealing Hospital.

CONSENT FORM

Visual Illusions study

Researcher : Miss Tracey Brown

Sub-Department of Clinical Psychology University College London

Torrington Place London Wl

To be completed by the volunteer:

Have you read the information about the study?

Have you had an opportunity to ask questions and discuss the study?

Delete as Necessary: Yes/No

Do you understand that you are free to withdraw from this study at any time, without giving a reason for withdrawing and without affecting your care in any way?

Do you agree to take part in this study?

Yes/No Yes/No Yes/No Signature of volunteer Name Date Signature of researcher Name Date

INSTRUCTIONS FOR EXPERIMENT 1 • The experiment starts with trial 25, which is an example of the test.

This test comes in three parts and this is the first part. Can you see the cross in the centre of the screen? If you look at this you will see that it changes to a letter. I want you to keep looking at the letter all the time. As the letter appears you will also see some objects out of the comer of your eye on different sides of the screen. All you have to do is to say yes or no if you see a red triangle amongst the objects. Can you see a red triangle here? Good, so all you need to say is ‘no’. Can you see a red triangle here? Good, so all you need to say is ‘yes’. Don’t forget to look at the centre of the screen all the time and say yes or no if you see a red triangle. The objects will flash up on the screen very quickly. Are you ready?

In document An investigation into illusory conjunctions and context-processing in schizophrenia: Differential relationships between symptoms (Page 117-120)