Wrong stimulus order and size in eye tracking experiments
I've faced with a problem of stimulus presentation that causes wrong experiments' procedure and stimulus size.
In the experiments, a fixation is presented followed by a blank, and then stimulus images are presented followed by a blank. These presentation times are fixed.
Unaccountably, sometimes the procedure is messed up. In many cases, the stimulus image that becomes much bigger size (full screen size) than the original one is presented when the blank should be presented. Additionally, the stimulus image that is the same size as the fixation is also presented when the fixation should be presented. The inappropriate stimulus is always a same image.
In this bad case, I have to quit the experiment, and copy it to create a new same experiment file (.osexp), enabling to run the experiments correctly.
What's the cause and how can I run the experiments without any copying?
The experiments are controlled by opensesame3.0.7, expyriment0.8.0, under Mac OS using Eyelink eye tracker.