Disclaimer: I’m new to Psychopy and Coding so if more information is needed about my circumstance to gain a better understanding please let me know how I can help you help me.
About the Task:
This is a variation of an attentional blink task.
One session consists of five blocks. One block consists of 10 trials. One trial consists of 17 images each presented one after the other for 100ms/image. However, 15 of these (Background) images must be randomly selected from a set of 252 images, one of these (T1 Images) from a set of 115 images and one (T2 Images) from a set of 84 images. Furthermore, the presentation of these images has to occur pseudo-randomly such that T2 is always displayed either 2 (called Lag2) or 8 (called Lag8) images after T1. The pseudo-randomization continues in that Lag2 and Lag 8 sequences can only occur if the T1 image is in the 4th, 5th, 6th, 7th, or 8th spot of the total 17 image sequence. Ultimately this results in Psychopy needing to display both lag2 and lag8 iterations (10 iterations [trials] total), in a shuffled order. From that shuffled order, Psychopy then needs to randomly select images from their respective categories and display them according to the trials’ lag iteration.
I was able to get the task to work without crashing. However, I cannot get the stimuli to be presented without some frames dropping or there being a delay in their presentation. For example, some images might stall and display for 150ms and the next image will only be displayed for 50ms. Timing is crucial to this task.
What I have done:
Setting the duration (s) to stop at my routine at .1sec has produced the worst result (whole images being dropped from the presentation)
I am using a Windows Dell Laptop and I know the frame rate is 60hz. With one trial lasting 1700ms, my understanding is that one image would need to be presented for 6 frames to equal 100ms in duration. I tried to set the Basic Image Properties to Start frameN = 0 and Stop frameN =6. However, the images are still not displaying at exactly 100ms.
I would greatly appreciate any suggestions on ways to troubleshoot this problem.