Deary-Liewald Reaction Time Task Standard Operating Procedure

Transcription

1 Deary-Liewald Reaction Time Task Standard Operating Procedure Installation Instructions: You will need a computer which runs Windows XP or Vista and a standard keyboard. We recommend using a screen with a vertical refresh rate of 60Hz or better. Click on the download link on the website page. A dialogue box will appear with instructions that will guide you through the installation process. The dialogue box will disappear when the installation is complete. Once it is installed, to open the programme go to the "Start" menu, and then All Programs Deary-Liewald Reaction Time Tasks DLRT. Test Setup: The main dialogue box is titled Deary-Liewald Reaction Time Tester. It displays a space for the Subject ID at the top, and three sections below with the titles Simple Reaction Time, Choice Reaction Time and Defaults, each containing various options and settings. The default settings and how to adjust them are described in the Adjustments to the Test section below.

2 Running the Test: Enter the Subject ID in the space provided. Make sure the participant is sitting comfortably with the computer and keyboard on a table in front of them. (a) Simple Reaction Time Click Run SRT practice. Confirm Test Start in the following dialogue box. Say: First of all you will have a practice session. A cross will appear in the box on the screen 8 times and each time it appears you should press any key as quickly as you can. Don t hold the key down, but press and release it when the cross appears. Use the index finger of your preferred hand to press the key throughout the test. When you are ready, press any key to start. At the end of the practice a message will read Test Completed Thank You!. Wait a few moments for the screen to disappear. Check the participant understands what to do. Click Run SRT Test. Confirm Test Start in the following dialogue box. Say: Now a cross will appear another 20 times and you should press any key as quickly as you can, as in the practice. When you are ready, press any key to start. At the end of the test a message will read Test Completed Thank You!. Wait a few moments for the screen to disappear. You can abort the experiment at any time by hitting the Escape key on the keyboard. N.B. If a participant holds a key down instead of releasing it, the cross will remain on the screen and the next trial will not begin until the key is released. Also, if a response falls out of the response range, it will not be recorded and will be replaced by another trial. (b) Four Choice Reaction Time Say: In this test there will be four boxes on the screen. A cross will appear in one of them and you have to press the correct key for that box as quickly as you can. Click Run CRT practice. Confirm Test Start in the following dialogue box. Say: When the cross appears in the box on the far left press the z key (point to each), when it appears in the box one from the left press the x key (point to each); when the cross appears in the box on the far right press the full stop key (point to each) and when it appears in the box one from the right press the comma key (point to each). Place the middle and index fingers of your left hand over the z and x keys like this (indicate which keys) and the index and middle fingers of your right hand over the comma and full stop keys like this (indicate which keys). As before you will have a practice of 8 crosses first. Remember, a cross can appear in any of the four boxes. When you are ready, press any key to start. At the end of the practice a message will read Test Completed Thank You!. Wait a few moments for the screen to disappear.

3 Check the participant understands what to do. Click Run CRT Test. Confirm Test Start in the following dialogue box. Say: You will now see another 40 crosses appear one after another and you should respond as quickly as you can by pressing the correct key, as in the practice. When you are ready, press any key to start. At the end of the test a message will read Test Completed Thank You!. Wait a few moments for the screen to disappear. You can abort the experiment at any time by hitting the Escape key on the keyboard. N.B. If a participant holds a key down instead of releasing it, the cross will remain on the screen and the next trial will not begin until the key is released. Also, if a response falls out of the response range, it will not be recorded and will be replaced by another trial. Adjustments to the Test Number of Trials: You can adjust the number of practice trials and experiment trials in both the Simple Reaction Time and Choice Reaction Time tasks. To do this, simply type in the number of trials you want to use. Response Range and Inter Stimulus Interval: You can adjust the Response Range and Inter Stimulus Interval for both the Simple Reaction Time and Choice Reaction Time tasks. To do this you simply type in the times you want to use. - Response Range is measured in milliseconds and is the range of reaction times for which the response is recorded. If a person s response is outside of this range, it will not be recorded. For example, if the Response Range is from 150ms to 1500ms, a response of 100ms will not be recorded. - Inter Stimulus Interval is measured in milliseconds and refers to the gap between each response and when the next cross is displayed. The Inter Stimulus Interval specifies the longest and shortest gap permitted, and the crosses appear randomly within these boundaries. Response Keys: You can adjust the keys used in the Choice Reaction Time task. To do this you simply type in the keys you want to use. CRT key box 1 corresponds to the box on the far left of the screen, CRT key box 2 corresponds to the box second from the left, CRT key box 3 to the box third from the left, and CRT key box 4 to the box on the far right. Defaults: You can save any adjustments by clicking the Save Defaults button, and then load them up later by clicking the Load Defaults button. The original defaults for the task are as follows: Simple Reaction Time: Number of Practice Trials = 8 Number of Experiment Trials = 20 Response Range = ms Inter Stimulus Interval = ms

4 Choice Reaction Time: Number of Practice Trials = 8 Number of Experiment Trials = 40 Response Range = ms Inter Stimulus Interval = ms CRT Key Box 1 = z CRT Key Box 2 = x CRT Key Box 3 = comma CRT Key Box 4 = full-stop Viewing the Results The results of the Simple Reaction Time task and the Choice Reaction Time tasks are saved to a database with file name dbsys. This is an application (.exe) file and is located in the directory C:\DL_CRT. To access the database, go to My Computer Local Disc (C:) DL_CRT dbsys. The database can also be accessed via the Start menu: Start Menu All Programs Deary-Liewald Reaction Time Tasks DB Manager. Once you have opened the database, go to File Open Table on the main toolbar. A dialogue box will appear titled Select table(s) to open. In the Available Databases section, make sure the scroll menu is displaying C:\DL_CRT\Data. If this is not available on the scroll menu, click on the Select button to the right. A new dialogue box will appear titled Browse for Folder. Click on My Computer Local Drive (C:) DL_CRT Data. Click OK. C:\DL_CRT\Data should now be displayed in the scroll menu. In the Available Tables section there should be four options. Data from the Simple Reaction Time task is stored in the SRT_Detail table and the SRT_Summary table. Data from the Choice Reaction Time task is stored in the CRT_Detail table and the CRT_Summary table. Click on the table you wish to view and then click open. Once the table is open, you can export the data by going to Action Export on the main toolbar. A dialogue box will appear titled Export Options for [name of table]. Click the Select button on the right and another dialogue box will appear titled Enter a name for the export file. Type the file name followed by.csv in the space provided. For example, if you wanted to call the file CCACE example, you would type CCACE example.csv. Select the location where you wish to save the file using the Save in scroll bar at the top. Click Save. You will return to the Export Options for [name of table] dialogue box and the title and location (URL) for the file should appear under the File Name section. Click Continue. A CSV file will then appear in the location specified. This file can be opened and edited with Microsoft Excel and other applications. The column headings used in the database tables are listed and described below: SRT Detail: Pid Run_number Correct_response Subject_ response Correct Response_time Particpant ID Order of trials What the correct response should be The response that the subject made If the subject response was correct or not (True or False) How long it took to respond (in ms)

5 SRT Summary: Premature_responses Anticipated_responses Count Mean Median Variance Stddev Skewness Kurtosis Mac_address Start_time Responses made prior to the stimulus presentation Responses made after stimulus presentation but before start point of the defined response range Total number of responses Mean response time Median response time Variance of response times Stddev of response times Skewness of the distribution of response times Kurtosis of the distribution of response times Computer Identification Time and date the experiment was started CRT_Detail: Pid Run_number Correct_response Subject_ response Correct Response_time Cr_time Wr_time Isi CRT_Summary: Premature_responses Anticipated_responses Correct_Count Correct_Mean Correct_Median Correct_Variance Correct_Stddev Correct_Skewness Correct_Kurtosis Wrong_Count Wrong_Mean Wrong_Median Wrong_Variance Wrong_Stddev Wrong_Skewness Wrong_Kurtosis Mac_address Start_time Particpant ID Where the response was What the correct response should be The response that the subject made If the subject response was correct or not (True or False) How long it took to respond (in ms) Response time for correct responses (in ms) Response time for incorrect responses (in ms) Inter-Stimulus Interval Responses made prior to the stimulus presentation Responses made after stimulus presentation but before start point of the defined response range Number of correct responses Mean response time for correct responses Median response time for correct responses Variance of response times for correct responses Stddev of response times for correct responses Skewness of distribution of correct response times Kurtosis of distribution of correct response times Number of incorrect responses Mean response time for incorrect responses Median response time for incorrect responses Variance of response times for incorrect responses Stddev of response times for incorrect responses Skewness of distribution of incorrect response times Kurtosis of distribution of incorrect response times Computer Indentification Time and date the experiment was started A help file for the database titled dbsys is located in the directory C:\DL_CRT\Data.