Equal Number of Correct Trials Per Condition

Support
1

Hi Chris,

I am sending you a simplified experiment with 3 conditions, distance (2 levels, 0 and 1), SOA (2 levels, 250 and 283.33) and target location (2 levels, 0 and 1). Therefore, it will create 8 conditions (2x2x2). This is implemented by three range replicators. In the actual experiment there will be 16 SOA levels and more than 1 trial per condition. But in this example there will only be 1 trial per condition, thus 8 trials.

Participants have to press “Y” in the Fixation task system state to continue to First Disc, this will be considered a correct trial. The particular condition (e.g. distance = 0, SOA = 283.33, target location = 1) in the correct trial won’t be presented again. If they press “U”, then the trial will be aborted and it is considered as an incorrect trial. What I want is, if the participants press “U” in a particular condition (e.g. distance = 1, SOA = 250, target location = 0) then that trial won’t be counted to the total number of correct trials and that condition will be presented again some time in the future (but not exactly after the incorrect trial so that participants can’t predict what is going to be presented next). As if that condition has never been presented.

In the end, what I want is 8 correct trial, exactly 1 correct trial for each unique condition. Is there a way to achieve this?

I have tried using reject selection of New Trial in when the participant press “U” but then, all conditions that have been presented are presented again. Therefore, I don’t have exactly 1 correct trial per condition.

Please tell me if my question is not clear enough. I will try to make it clearer.

Thank you for any help you can give.
Tenri

2

Hi Tenri,

Did you mean to attach an experiment to your message? If so, I didn’t receive it.

I have tried using reject selection of New Trial in when the participant press “U” but then, all conditions that have been presented are presented again.

It sounds like you’re missing an accept selections action when the participant presses “Y”. This will “commit” the trial, so that subsequent invocations of reject selections won’t put it back in the pool.

Cheers,
Chris

3

Hi Chris,

Thank you for the quick response.

Yes I meant to attach my experiment but somehow it wasn’t attached, sorry about it. I attach it again.

I tried adding an accept selection after “Y” and it works now. But would you be so kind to take a quick look at my experiment and say what you think (e.g potential problems, better way to factorise conditions, problem with trial acceptance etc.)? I promise it’s not a complicated experiment.

Thank you
Tenri

4

Hi Tenri,

Sorry for not replying sooner. I was out of the office for several days around the Thanksgiving holiday.

But would you be so kind to take a quick look at my experiment and say what you think (e.g potential problems, better way to factorise conditions, problem with trial acceptance etc.)?

It looks soundly designed to me. I don’t see any issues.

Cheers,
Chris

5

Hi Chris,

Thank you very much, that is helpful!

Best,
Tenri