This article applies to:
E-Prime Extensions for EyeLink 3.0
ELVaryingPositionIATracking tests a participant's ability to identify a letter of certain physical orientation among a group of other letters.
ELVaryingPositionIATracking presents a letter in a physical orientation first, then shows many letters in several different orientations. The task is to find the orientation that matches the orientation of the first letter shown and press the one key once the letter with the same orientation is located.
As you fixate on a letter during the Stimulus presentation, the BorderColor changes to show that the letter is currently being gazed at.
For analysis, a message is sent to the .edf file that specifies where the position for the target letter is. This is done through an OnsetTime Task Event on the Stimulus object.
ELVaryingPositionIATracking_SlideButton demonstrates a secondary way to accomplish the same task using SlideButtons. Notice that because it is using SlideButtons instead of SlideText sub-objects to present the letters, no InLine script is used to determine which letter is being gaze at. The SlideButton change the BorderColor to green when hovered on.