INFO: Piloting E-Prime Extensions for EyeLink studies prior to data collection [34197]

This article applies to:

E-Prime Extensions for EyeLink 3.0

Detail

E-Prime Extensions for EyeLink offers certain PackageCalls and parameters that are beneficial for piloting experiments before deployment with participants. Psychology Software Tools encourages piloting before running with participants not only to ensure the experiment is functioning correctly, but also for saving stimulus display information to the Output folder for EyeLink-enabled experiments.

Before adding in any EyeLink functionality, you should pilot the experiment. This is to verify that the basic E-Prime functionality of the experiment is working. Whenever EyeLink is enabled in the experiment, you can still pilot the study with EyeLink turned off. You can accomplish this by changing the strState parameter of the ELOpen PackageCall to “off.”

The PackageCall routine EyeLink_GazeReplay is specifically made for the purpose of verifying data before running with participants. This call shows where participants were gazing during a trial. It can help researchers identify issues with the eye tracker setup or the experimental design if the gaze replay shows unexpected or inaccurate results. Identifying issues with gaze data is imperative since having accurate data is a necessity in eye tracking studies. Psychology Software Tools and SR Research both recommend removing this PackageCall before running with participants.

NOTE: The PackageCall ELOpen offers a parameter named vReserved01. This parameter can also be used for piloting. We recommend contacting PST for more information.

Lastly, PST recommends piloting all conditions of your experiment before deploying it with participants. This ensures that all the display objects are saved in the Output/Resources folder of the experiment. This improves experiment timing because display objects and interest areas are not added to the Output folder during time critical trials. The EyeLink Resources Added to Folder (Inefficient Composite) Experiment Advisor Module occurs when resources are added to the Output folder during a study (see INFO: Listing of E-Prime Extensions for EyeLink Experiment Advisor Modules [34293]). However, note that any images that use transparency or overlap with another image are added as display objects regardless of piloting.

If running on multiple machines, we recommend piloting all conditions fully on one machine. Then, transfer all files (e.g., .es3, Output folder, etc.) to the other machines running the experiment. This ensures that the other machines do not have to create new resources during data collection as well.

NOTE: If resources or display stimuli change during the course of a study in terms of size, color, etc. be aware that you need to pilot again to ensure Output resources for all conditions are created.