How do we use Superlab conceptually.

Transcription

1 How do we use Superlab conceptually. Superlab is constructed in 4 sections: 1. The compilation of the stimuli. This takes place outside of Superlab by the researcher producing pict file pictures in a paint programme or other stimuli for importing into Superlab as an event. 2. The decision of how many Blocks are required. A block is a set of trials which in turn are linked to events. You can have as many blocks as you need. These can be randomised or not depending upon the type of experiment you wish to conduct. 3. The Trials. A trial consists of events (stimuli). A trial can be linked to any number of events. In the case of the category specific experiment, each trial will be linked to two events a stimuli and a 2 second dead time delay. 4. The Events. An event is the display of a stimulus or a dead space or a set of instructions. All of these will be used in the category specific experiment. We can illustrate the hierarchy of Superlab thus: Block Block Trial Trial Trial Trial Event = Instructions Event DS Event DS Event DS Do not assume Superlab knows what you what to do! Each step is controlled by the researcher. You will have to ensure you programme Superlab to: a. Recognise the response keys you have selected as appropriate for the experiment b. That the stimulus is removed from the screen when a response is made. This can be regardless of whether it is correct or incorrect, or only when the correct response is made.

2 c. That the stimuli will be presented randomly. d. That the events will have individual titles when saved in Excel for indentification. Compiling the Category Specific experiment in Superlab. The stimuli (pictures) will be found in Psy Course Data on the student server. Step 1. Create a new folder on your machine's hard drive in the Local User Area. Give it a recognisable name. Step 2. Open the student server select Psy Course Data, close server. Select the appropriate folder and copy the folder to your new folder on your local hard drive. Step 3 Open Superlab from Applications and save it into your new folder so that you have the stimuli and the Superlab script in one folder. Close down the Super lab application. Step 4 Open your folder, double click on the superlab script file. You will see a window like this. We have already talked about Blocks, Trials and Events so let's start to build our experiment. Step 5 On the tool bar at the top of the screen you will see Experiment, by clicking here you will be able to access the experiment editor. Go to Experiment and Input. Here you should select ADB Keyboard as we are going to ask participants to press a key on the Mac keyboard as their response.

3 Step 6. We now have to allocate response keys to the keyboard. Go to Experiment, Response Editor. Click the New button and type the letter c and press OK, this sets the response for complete. Click the New button again and type the letter N and press OK, this sets the response for not complete. Click on new once again and press the space bar a blank space should appear in the box, click OK. Click on the white square in the top left corner to close this window. Instructions We need to input the instructions to the participants to be shown on the screen. Click on New Block a window will appear asking you to name the block - call it Instructions.. Click on New Trial call the trial instructions it should not be randomised, it will only be shown once. Click on New Event and find the instructions file, we have already set up the response for this as being the space bar, ensure we have chosen the correct response box. We do not want feedback from this event Blocks Create our stimuli Block 1 by clicking on New Block. A window will appear asking you to name the block - call it Block 1. You will then be asked if you want to randomise the trials - the answer is yes, and 0 is OK for the seed. Events We will now start to create the events, these are the stimuli displays. The 1 st event to be created is the time that a blank screen will be displayed between the stimuli. Click on New Event, in event name type "dead time", uncross the accepts user input box as we do not want our participants pressing the keyboard and putting all sorts of strange data into our file. In the time box put 2000 mlsecs. In the event type we will always have visual. Trials We now have to create a trial for the dead space. Click on New Trial, type dead time in the naming box and cross the For feedback only box.

4 You have now created the first part of the experiment, the white space that will be shown in between the stimuli. This event must be clicked on with each single event so that it appears after the stimuli. Stimuli Events Now we have to organise the stimuli in Superlab so that it can be displayed. Go to New Event Click on Picture you should then go through the menus until you come to your folder that you created with the stimuli in. Open Living and you will see Living complete, Living incomplete 1 and Living incomplete 2. We will put in all the living complete stimuli first and then Living incomplete 1 not 2 at this stage. In the event name call it Cat. Comp always put the name of the animal or object first so that it can be sorted in Excel later. The type remains as visual, we do not want to set a time limit, we want the stimuli to accept user input so keep a cross in that box. The picture will be removed only after a response but it does not have to be the correct response, so any key is OK. In our case the correct response is C so put that in the correct response box. Click on Feedback, and if response is correct the feedback will be dead time, if you click on that box you will see it as an option. If the response is incorrect the feedback will also be dead time. The feedback after no response is no feedback, click OK and your first real event has been created. Now you must link the events together into a trial. Click on New Trial name the trial Cat.Comp. The Most important thing to do now is to link Block 1 with trial Cat Comp and 2 events - Dead time and Cat.Comp. Do this by Clicking on Block 1, then Clicking on Trial Cat. Comp and making sure the diamond goes black, then click on Dead time and make sure that diamond goes black and Cat.

5 Comp whose diamond should also go black. The Block, Trial and Events have now been connected. Continue to carry out this procedure for each of the stimuli in Living Complete, linking Block 1, with each new event and each new trial including dead time each time. Continue then to input the stimuli from Living Incomplete 1. Make sure you call the trials and events e.g. Cat.Incomp1 so that we can identify them in Excel later. Continue then to do the same thing for Non Living Complete and Non Living Incomplete 1. These will also go into the same block 1 but will also each need to have 1 trial matched with the corresponding event and dead time. By putting everything into the same Block and randomising the trials you will be able to display all 48 events randomly. Make Sure The event is followed by the Dead time, Dead time should always be at the top of your window. You specify dead time as feedback for correct and incorrect responses for each event. Block 1 is tied with all the trials and each trial is tied with 2 events, a picture and dead time. From Excel to SPSS 1. Your data will have been saved into an Excel spreadsheet, to get it into the right format to analyse in SPSS follow these steps: 2. Set up your data sheet in SPSS with the variables in alphabetical order. This can then be closed until required. 3. Delete from the top of your Excel data set the information we don t need and the reaction time for the instructions. 4. Highlight all of the data set go to data sort. Sort ascending the column with the correct or error response codes C or E. 5. Highlight only the errors including the stimuli name and the reaction time. Copy and paste them to elsewhere on the page. You will need to deal with these in the appropriate manner that you choose.

6 6. Highlight the complete data set and sort again but this time by the column with the stimuli names. 7. Highlight only the reaction times making sure you have no empty cells highlighted. 8. Go to Edit copy then click on any cell at the top of the spreadsheet that has enough room for the reactions times to be pasted in a row. 9. Edit - paste special and click the box for transpose. Your data will now be in one long row. 10. You can now copy and paste this data row into your SPSS data set, or if you prefer copy and paste the rows into another excel spreadsheet until you have completed the procedure for all the subjects and then copy it over altogether.