Experiments Once you have created your resources, written your script, and saved it in the same folder at the resources, you are then ready to start your experiment. Phew! You can call each experimental session by a unique name if you like by clicking on the Session Name that appears in the box at top right of the script editor. This is used in the log window's results and for any sounds that you may record using voice activation. 1. To start the experiment: You can either (i) click the Run menu item under the Control menu; (ii) click the play button at the top of the script editor window; or (iii) type Command-/. MacStim will first parse the script, evaluating, checking and preparing each line. If no errors are found, then a dialog box will be presented telling you MacStim is ready to initiate the experiment. When you click the OK button, you will see a flashing mouse-like cursor. This indicates that when you next click the mouse, the experiment will start immediately. This allows time critical experiments to begin exactly when you want (and reduces the overhead of removing the dialog box etc). You can elect to have no dialog box at all (in the Preferences experiment options). Clicking the OK button on the dialog will commence timing. You can eliminate this dialog completely by checking the "Don't display initiation alert" in the Preferences, and cause the test to commence as soon as all resources are loaded. 2. To stop an experiment: Press the Command-. (ie command and period keys) combination. 3. To pause an experiment: Press the Command-, combination (ie command and comma). To restart after pausing, just hit the Command-/ (command and slash) combination again. You can also restart the experiment from the beginning (without having to reload (ugghh!) all your resources by pressing Command-0 (ie command key and the zero key) after you have paused the experiment. If you have elected to have the initiation alert appear at the start of your experiment, then it will again appear, otherwise the experiment will instantly restart. If you have elected to have a triggering stimulus at the start then this will need to occur before it will restart. 4. To test some selected lines: Select the lines you wish to test in the script window. Choose the Run Selected Lines (or Command-1) menu item and MacStim will attempt to run just those lines. The caveat is that in blocks (either random or block trials types) you must have the top line's repetition time (rep) above zero seconds or else MacStim assumes you wish the block to be played in zero seconds, so it shows/sounds nothing but just cycles rapidly. Pretty pointless! Another method is just to comment out those lines you don't wish to play. Use the Control menu's commands to make this faster for selected lines. 5. To work out the loading times for resources: Select the lines containing the resources for which you wish to compute the loading times, and then select Compute Load Time under the Control menu (or Command-2). Each resource will be loaded as during an experiment from scratch, and then the time taken recorded in the Log Window. Note that these are worst-case estimates and can vary depending upon background activity going on at the time you choose to compute the times. Actual load times (if required) are recorded during the experiment in the Log Window and may be considerably less, especially if the file has resources which remain loaded in memory. There are also other controlling options available under the Preferences menu. In particular, note that you can either run the experiment or create a script which would run the experiment if saved and started. The reason for the later option is to allow you to create several random trial combinations which can then be saved and you can ensure they are exactly replicated on a subsequent occasion.