Fixation cross change in colour

Hi there,

For my experiment, I have a central fixation cross that is present throughout the entire experiment. I have used the polygon component for the fixation cross. The fixation cross is black, but 400 ms after stimulus offset, I wish to change the colour of the fixation cross from black to a light grey colour, as this signals the need for participants to make a response. How do I do this, while ensuring that after the primary response is made (and on the next trial after), the fixation cross turns back to black and then again to grey for each trials?

Thanks in advance!

The easiest way to do this would be to use a second routine.

The presentation routine would have the black fixation cross and the stimulus

The response routine would have the grey fixation cross and the keyboard/mouse component.

Hi, thank you for your response! That sounds like a much easier way, but how would I go from the trial routine with the black fixation cross and the stimuli to the second routine with the grey fixation cross and the button responses without a response component in the trial routine?

In the trial routine you don’t have any response possible so your components would all need fixed durations so they all end at the same time.

That makes sense. But I would also need to have a fixation cross constantly throughout, i.e., between the trial routine and the other routine with the grey fixation cross. Does that make sense?

The trial routine could have, for example, a black cross starting at 0 seconds and lasting for 2 seconds and a stimulus starting at 0.5 seconds and lasting for 0.5 seconds.

Thank you!!