randomization of events

Hello!

I am working on an experiment and i am trying to randomize events. in one trial i’d like to have a fixationcross, followed by a picture and one of 15 masks that are randomized. i don’t want the 15 masks to follow in a randomized order i just want one mask to be shown after the fixationcross and the picture. is that possible somehow?

your help is much appreciated!!!:slight_smile:

Is the picture after the fixation constant? Do you want to eventually show each of the fifteen masks once?

I need a little more information. You’ve told me about one and only one trial. I can tell you how to do this for one trial, but obviously, you want more than one trial, and how that would be done depends on the requirements for the additional trials.

This should be the design (total 60 trials)
Event 1: fixation cross
Event 2: one of 60 different pictures (random without replacement)
Event 3: one of 15 different masks (randomly assigned)
Event 4: Evaluation of stimuli (event 2)

Hi,

You’re going to have to do some juggling to get what you want here.
Let me try and describe what you have to do.

Event 1 will need to be the LAST event of the PREVIOUS trial.

Event 2 will be a stimulus list of images which is, by default, random without replacement.

Event 3 will have to actually consist of 15 events. Each event displaying a mask. Now, each of the events here need to provide Feedback. So you’ll have to go through these events and Provide Feedback If Always, at the end of the event. And for What To Do: Present event 4 Evaluation, Present event 1 Fixation Cross, Skip remaining events and present next trial in this exact order. So, you’ll have 15 events that will have feedback set up this way.

Event 4 will also need Feedback. So, Provide Feedback If Always, at the end of the event. And for What To Do Present event 1 Fixation Cross. Just have this, and only this for What To Do.

Now, to take care of the randomizing of the events. The trail that does that randomizing should include Event 2 (stimulus list) and the 15 events for the masks. Edit the trial and check Randomize the events in this trial and also check Except the first one. The first event in this trial should be Event 2.

That should do it. Remember that Event 1 needs to be the LAST event of the PREVIOUS trial
Also note that Event 4 isn’t part of any trial. It’s just a feedback event.

I’ve attached an example experiment to help make this clear.

Hong

experiment.zip (369 KB)

Thanks!

Hello!

sorry that i reply so late. thank you very much for your help, we finally managed to get the frame of our experiment. we also had to deal with some other problems but it looks really good so far. it’s great to have people like you who know all the tricks of superlab.

p.s: but i’m really looking forward to a manual, things would be sooo much easier ;)!:slight_smile:

feedback after 10 seconds timelimit

Hello!

we’ve encoutered a new problem. After the evaluation we would like to have an event that tells the subject, if it didn’t react within 10 seconds, that it was too slow, and that we would like for it to react a little faster the next time. We don’t want this event to show when the person gave a correct answer within the time limit.

Event 1: fixation cross
Event 2: one of 60 different pictures (random without replacement)
Event 3: one of 15 different masks (randomly assigned)
Event 4: Evaluation of stimuli (event 2)
Event 5: But only after 10 seconds if subject didn’t react

We hope that some of you might find an answer to this problem, help is, as always, much appreciated!:cool:

How this would be configured depends on whether you want the user interrupted.

If you do, set a time limit on event 4. Also, set a feedback on event 4 such that if “the reaction time is too quick” you “skip any remaining events and present next trial.” This naming is a little counter-intuitive for your situation, but the behavior will wind up being what you want. (event 5 will be linked to your trial).

If you don’t want the participant interrupted, then all you need is a feedback on event 4 to present event 5 if the response is too slow (event 5 will not be linked to your trial).