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fixation cross location using yoked trials
#10
Hi Anna!

We have a couple of solutions for you. The first one is a bit hacky but should be quick. The second one is a "proper" solution but may require a bit restructuring of the trial templates. Let me describe them first. Wink

Solution 1

Right now the fixation cross is at the dead center of the screen (as it should be), but the tokenized text stimulus on the next trial gets pushed up a bit by the ensuing choice response. Does the fixation cross needs to be at the absolute dead center? If not, we can manually push up the cross a bit, assuming the fixation cross is implemented with a "+" character in a text stimulus, so that it lines up with the tokenized text stimulus.

This is relatively easy because you can HTML to the "content" of a text stimulus. We can add an empty invisible paragraph below the fixation cross like this:

Code:
"content": "+<p>&nbsp;</p>"

You can repeat the "<p>&nbsp;</p>"  thing (which is saying "add a paragraph on a new line with just a space in it") as many times as needed to line them up.

This solution is hacky in spirit, but it's actually pretty quick and effective.

Solution 2

Now if you need the fixation cross to be at the absolute center, or you'd just want a more robust solution, here's another way. We could put the timed choice responses on a separate trial template (yes, it's okay for a trial template to just have responses with no stimuli) and then yoke three templates together. That is, you'd be yoking:

"fixation_cross_template", "singleton_reading_template" (my name for it), and then a "speeded_choice_template" (also my name) template

together. Because the three elements (fixation, prime, target) are now on three different trials, all of them will be at the dead center of the screen.

Looking at your code, I don't think it would introduce additional arbitrariness to your setup because you are already manually lining up the tokenized text stimuli and choice responses. The difference is that right now, they are lined up within the same trial template via the "stimuli" and "responses" mapping. This new approach would instead do it between trial templates.

(sorry couldn't pass an opportunity to be nerdy about within and between designs. haha)

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What do you think? My personal preference is Solution 2, but it is a bit of an overkill. Smile
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RE: fixation cross location using yoked trials - by Ting - 10-23-2021, 04:15 PM

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