Newbie

matopos · April 2020

Hi, I am very new to this so please excuse my lack of experience.

I am designing an experiment that comprises 12 visual stimuli which will appear in sequential triplets, hence they have to appear together in groups of 3 (eg pic1, pic2, pic3 have to appear in that order). This all works fine. However, sometimes one of the triplets will be repeated twice, eg. pic1, pic1, pic2, pic 3. Please advise how I can define this in - is this a run if statement? Furthermore, if a picture is seen twice, participant has to verify that they have noticed this. How would I set this up? This would only be when a picture has been shown twice in a row, not with normally appearing triplets.

Thank you in advance!

Daniel · April 2020

Hi @matopos

You are on the right track. If it's always one of the three pictures that need to be repeated, you can possibly realize this in a run_if statement. For instance, if your loop item looks as follows:

Picture1   Picture2    Picture3    Repeat
pic1.jpg   pic2.jpg    pic3.jpg    0
pic2.jpg   pic1.jpg    pic3.jpg    2

then in the sequence item that you have embedded in the loop, you could do the following:

Items                           Run if
======================================
Picture1_sketchpad              always
Picture1_sketchpad         Repeat == 1
Picture2_sketchpad              always
Picture2_sketchpad         Repeat == 2
Picture3_sketchpad              always
Picture3_sketchpad         Repeat == 3

Thus, the `Repeat` column in the loop item determines which item needs to be repeated, with 0 (or any other value than 1, 2, or 3) indicating that there is no repetition.

Make sure the sketchpads display the corresponding images by using the variables you set in the loop item (e.g. `[Picture1]`).

Just as a sidenote: It helps us a lot of the title of your post is representative of the question that you are asking, and not a random term like newbie! Thanks :)

I hope this gets you started!

matopos · April 2020

Hi Daniel, thank you so much for replying and I am sorry for posting twice. I thought that my first post was not that clear. I'll be sure to use more informative terms in the future as well :)

I have tried the above but am still running into some problems which will be due to my inexperience.

The first part of my experiment is based upon 12 pictures grouped into one of four base triplets, ie. ABC, DEF, GHI, JKL. Each of the pictures is shown 18 times and in addition to this, also repeated triplets which are 2 x AABC, ABBC, ABCC and so on (eg. DDEF, DEEF, DEFF) and the same for the other triplets.

At the moment, in my loop, I only have one column called base triplet with letters A-L underneath each other. Is this the correct way to set up my variables or should I set up 4 columns each corresponding to one of the base triplets and each column corresponding to a new sketchpad?

I then need to repeat the base triplets so they are shown 18 times each and the repeated triplets only twice each. How would I set this up?

Thank you for your advice.

Daniel · April 2020

Hi @matopos,

I'm sorry but I cannot completely follow your explanation. Generally if you place things underneath each other in a OpenSesame loop the this means it will be varied over trials: each row in a loop represents a trial. So if you want things to occur in succession in a single trial, you should try and fit your parameters on a single row and not underneath each other.

If you specify the unique combinations (that is order of images and which item should be shown twice) in the loop item, then you can use the repeat parameter of the list to repeat these combinations.

matopos · April 2020

Hi Daniel,

Thanks very much, I'll use this advice and try again!

:-)

matopos · April 2020

Hi Daniel,

I am sorry to bother you as I am sure you are very busy but I can't seem to find answers to my questions in the forum or on tutorials.

Just to explain a little more clearly, my experiment comprises 12 different images, which are represented in letters. The images occur in 'triplets' and have to occur together. ie, ABC, DEF, GHI, JKL.

I have amended my block loop so that it each row of the loop represents a different triplet (ie, row 1: ABC, row 2: DEF, row 3: GHI, row 4: JKL). The triplets are then set to repeat randomly, so that each triplet is seen 18 times.

However I will be repeating some of the letters and need to create another presentation to include the repeated picture, which would be AABC, ABBC, ABCC, ABCD and they only need to be shown twice.

I have tried to run them under a separate row but it doesn't seem to work. Would I set them up under a new sequence and if I do that, can I still randomise them against the other triplets ?

Apologies for all the questions. I have tried various different configurations and thought best to send you an image of what my screen looks like at present.

Once I have worked out this part, it will help me with the rest of the experiment. Thanks again for your time.

Daniel · April 2020

Hi @matopos,

No need to apologize, all beginnings are difficult. Have you tried the approach I outlined earlier in http://forum.cogsci.nl/discussion/comment/18905/#Comment_18905? If you add another column in which you define which triplet letter to repeat, you can use this in the embedded sequence item to show one of the letters again. If you don't want to repeat a letter in that trial, simply set the repeat columns value to 0. In my example, I named this column Repeat , but it can be anything else. If you then check for the value of this repeat variable in the sequence, and repeat the corresponding sketchpad item accordingly, you should be good to go.

Don't you also need to insert a blank screen between each letter? Otherwise the repeated letter will just seem to be shown twice as long as the other letters.

matopos · April 2020

Hi Daniel,

Thanks, this is v. helpful even if I'm appearing really dim ;-/

I tried the approach you outlined earlier and ran into some difficulty so please may I show you my current screens.. I must be doing something wrong.

The screenshot of my familiarisation sequence shows my triplets: ABC, DEF, GHI & JKL set to repeat 18 times (in the repeat column).

My repeated letters also run to a certain sequence, eg AABC, ABBC, ABCC (and similar for each triplet). I tried to do what you suggested but couldn't get it to work so thought to run each repeated letter as a trial - with a repeat of 2.

The above screen shows how I have tried to change the run if statements, is this the right way of doing it?

When I try and run the above sequence it won't run because I have a space in the first four trials.. how would I overcome this?

Thank you also for your suggestion of adding a blank screen between repeated letters, you are right, I do need this - please advise how I do this?

Thank you enormously!! You are very kind to help me out with this :-)

Daniel · April 2020

Hi @matopos.

Please look at the solution I posted earlier carefully. You don't need to have the extra column with the letter you want to repeat. You can simply repeat one of the earlier sketchpads. To add blank displays you can just insert empty sketchpads between the sketchpads on which you show the triplet letters

My earlier solution was:

Items                           Run if
======================================
Picture1_sketchpad              always
Picture1_sketchpad         Repeat == 1
Picture2_sketchpad              always
Picture2_sketchpad         Repeat == 2
Picture3_sketchpad              always
Picture3_sketchpad         Repeat == 3

but with the blanks and your nomenclature it would become:

Items                           Run if
======================================
blank                           always
triplet1                        always
blank                           Repeat == 1
triplet1                        Repeat == 1
blank                           always
triplet2                        always
blank                           Repeat == 2
triplet2                        Repeat == 2
blank                           always
triplet3                        always
blank                           Repeat == 3
triplet3                        Repeat == 3

You can then remove the triplet4 column from your loop. In the repeat column, you simple need to set the number of the triplet letter you want to repeat.

matopos · April 2020

Thank you Daniel for your patience, I am trying this now to see if I can make it work! Apologies, it must be very simple to those more experienced but I seem to be making a meal out of it! The blank sketchpad works a treat. I have inputted your advice exactly this time so that I have the following:

When I have inserted the extra sketchpads, I have copied them so that they are linked, ie. triplet1 sketchpad links to the second triplet1 sketchpad. Is it correct to link them?
The repeated letter does not run on rows 5-10. Not sure what I have forgotten to do?
My other question, is that I need the first 4 triplets: ABC, DEF, GHI, JKL to come up 18 times, but ones with the repeats, eg. AABC, ABBC, ABCC, only to come up twice. Is there a way to do this in the loop? At the moment I have just put two lines in to represent two trials but I'm sure this is incorrect.
I need participants to indicate when they have seen a repeated alien, do I set up a keyboard response with correct_response column?

Once again, thanks for your patience.

Daniel · April 2020

Hi @matopos

When I have inserted the extra sketchpads, I have copied them so that they are linked, ie. triplet1 sketchpad links to the second triplet1 sketchpad. Is it correct to link them?

That is exactly how you should do that, especially if you want the duration of each blank to be the same.

The repeated letter does not run on rows 5-10. Not sure what I have forgotten to do?

I see a couple of things that are out of the ordinary and could be the reason for this:

I think you forgot to add the run-if condition for the repeated triplet1.
In run-if conditions in opensesame, you need to encapsulate variables in square brackets, so change repeat == 1 to [repeat] = 1 . (in run-if fields you only need one = for a comparison, though two will work as well).

My other question, is that I need the first 4 triplets: ABC, DEF, GHI, JKL to come up 18 times, but ones with the repeats, eg. AABC, ABBC, ABCC, only to come up twice. Is there a way to do this in the loop? At the moment I have just put two lines in to represent two trials but I'm sure this is incorrect.

You can achieve this using a weights column. for more info see here: https://osdoc.cogsci.nl/3.2/manual/structure/loop/#weight. You need to set this using the script interface of the loop item, which can be accessed by the `open script` button at the top-right of the loop's page (left of the question mark).

I need participants to indicate when they have seen a repeated alien, do I set up a keyboard response with correct_response column?

Yes, you only need to set a correct_response column for this in which you set the correct key for each trial.

matopos · April 2020

Daniel, THANK YOU! I have made the corrections and the repeated letters work perfectly. Now I'm working on the weight column and keyboard response. Just wanted to thank you for all your help (and patience!) :)

matopos · April 2020

Hi Daniel, thank you. With all your help, everything is working well. I am now working on the rest of the experiment and have a small question.

I am now comparing the base triplets with 4 new triplets, which comprise of new letters (as before, each letter represents an image).

So ABC will appear on the screen followed by 4 new configurations - AEI, DHL, GKC and JBF. Participants will then be asked a question. Thereafter, the other base triplets will appear with the new configurations.

Please advise how I would set up the repeats in the loop without manually typing out the whole order? Is there a way I can order the repetition, so that ABC is followed by AEI, DHL, GKC and JBF, then the same for the next base triplet: DHL followed by AEI, DHL, GKC and JBF (and so on).

This is how my loop is set up so far.

I'm hoping that after this, I won't hassle you any more! Thank you once again.

ivan866 · April 2020

Not `run if`.

What you need is called 'permutation' or 'sampling with repetitions'. Find some method capable of that in NumPy or Pandas. That way you get a much more elegant solution, more reusable and far more readable code.

Daniel · April 2020

Hi @matopos ,

What are asking is indeed no easy feat. You can either choose to perform this permutation in an external program (such as Excel) and load in the complete permutated table in the loop item (by changing the source dropdown from table to file).

Otherwise, you could have a look at the page I referred to earlier: https://osdoc.cogsci.nl/3.2/manual/structure/loop/#advanced-loop-operations. There may be some functions there that help with this too, such as fullfactorial

matopos · April 2020

Thank you for the replies. @Daniel I was thinking about creating an excel table so will give this a go. Thanks again for your advice.

matopos · April 2020

Hi @Daniel

Sorry to bother you again. I am trialling different options with the rest of my experiment, it is proving quite tricky.

Small question, can I put multiple variables from my sequence on one sketchpad, or would each variable need a new sketchpad?

If I can use multiple variables on one sketchpad, what is the correct language to use when I edit them in the script, ie. [seq1]+[seq2]+[seq3]. ?

Thank you once again.

matopos · April 2020

@Daniel, apologies but please ignore previous question as I have tried something else which works & I am slowly making progress. :-)

I have set up 3 sketchpads which display 6 stimuli and then participants see a question after these 6 stimuli. This all runs well.

My query is with regard to logging answers to the question after every 6 stimuli. As the answer would be either A or B, I have used the multiple choice form. Is there a way to make the answer intuitive, so that it logs correct responses to certain sequences. ie, I only want 'A' answer in response to stimuli that represent certain stimuli which are called ABC, DEF, GHI, JKL.

Would I need a correct_response column in my sequence?

Thanks again for your time, I'm grateful for your help as always.

Daniel · May 2020

Hi @matopos,

your description of the problem is really hard to follow, and I guess you mean a correct_response column in your loop? I don't know how the order of stimuli is currently specified there so it's hard to say what you need to do. Perhaps you can add a screenshot again?

matopos · May 2020

Hi @Daniel thanks so much for your reply. I have now used a sketchpad for my question instead of the multiple choice form, as realised this would work better. Thanks again for all your help with this.

Howdy, Stranger!

Categories

Newbie

Comments

Howdy, Stranger!

Quick Links

Categories

Newbie

Comments