What are you trying to achieve?:
I am trying to display a fixation cross for 350ms before the onset of my stimuli. I have two sets of stimuli: images of bottles and images of words. There are multiple blocks in my experiment. In the first block, only the bottles are shown. In the second, only the images of words are shown. Then in the third, all the images are shown together. The length of these blocks and included stimuli are determined via a list multiplier in a code component. The fixation cross only seems to be displayed before the images of words, not bottles, even when they are shown together rather than separately.
What did you try to make it work?:
I have tried running just the images and fixation cross in a separate experiment, which works fine. It just seems to be in my particular experiment that the fixation cross will not be displayed before the bottle images. I have also tried swapping the bottle images in place of the word images, but that also did not make a difference.
Could anyone shed any light on why this would be happening?
The text stimuli you can see underneath the response should remain on the screen for the whole block of trials. I only have the one image component, which pulls both lots of stimuli.
The blocks are determined in a code component which is part of the instructions routine.
Your other text components occur at the same time as your fixation - it could be that they are overlapping with your cross. I usually just use a separate block for fixations which would remove that issue.
To work out what’s going on try removing the other objects again. At what point does the fixation come back? Also check your units. If in this study your window units are pixels (for example) and your letterheight is 0.1 then your fixation is being drawn at less than a pixel.
To test whether it is simply being occluded by your stimuli (as Oli suggests) you could right-click on your fixation object and select “send to bottom”. That means the fixation will be drawn last so it will be “on top” of the stimulus rather than the other way around.
Thanks for your suggestions. My lecturer noticed there was quite a large size difference for each set of files. Making them all the same size in the folder seems to have fixed the problem with the fixation cross.
