This tutorial shows how to make a basic Stroop experiment. A new tool we will learn about is the Slide object - a versatile object that can contain several sub-objects, such as images and text boxes. The Slide object's properties are controlled by the property pages tab, while the sub-objects are controlled by the sub-object property pages tab.
In addition, we review two important timing properties: Timing Mode and Pre-release.
Timing Mode deals with delays caused by background computer processes. Selecting the Event option makes the object stay on the screen for as long as the Duration, no matter what delays there are before presenting the object. For example, if the Duration is 2000ms and there was a delay of 10ms when presenting the object, then 10ms will be tacked on to the duration of the object: 1000ms + 10ms = 1010ms. Select this option if you want every instance of that object to be the same duration; in this example, so that every Stroop trial will remain on the screen for exactly 1000ms.
Selecting the Cumulative option means that the object will last for the specified Duration minus any delays. For example, if the Duration is 1000ms and there was a delay of 10ms, then the duration of the object will be 1000ms-10ms = 990ms. Including the delay, the entire duration of the entire trial will be 1000ms: 990ms (object duration) + 10ms (delay) = 1000ms. This minimizes any cumulative timing errors, which may be important for experiments which need to end at an exact time for all the trials to be collected.
By expanding your tools to include Slide objects and more advanced options, you can create an entire Stroop experiment. In order to make this process more efficient, however, we next turn to Procedures and Lists to create larger-scale, more flexible experiments.