Counterbalancing multiple blocks

VictorVarela

Hi all,

I'm new to OpenSesame. I'm trying to create an experiment in which participants will process a total of 5 blocks containing 20 trials each, resulting in 100 trials. However, for each block, trials are presented with different experimental conditions.

What I did runs as follows:

Main_loop contains 5 blocks [1,2,3,4,5] and is declaring every condition [N, W, T, A, N]. Main_loop will be running 5 times sequentially (in theory I should be shuffling middle conditions [W, T, A] too, but this is for another question here =p, if you can help me, thanks ).

However, on Block_loop (yes, I know that names should be inverted) I have my set of 100 trials to randomly show the stimuli 20 times.

It runs brilliantly, however, because Block_loop shuffles my trials every time I enter the loop, OpenSesame is showing some trials twice or more. How can I make this in a way that I present all 100 trials, but once each???

Thanks,

Victor

lvanderlinden

Hi @VictorVarela ,

Is it possible to upload your experiment, or at least the content of your block loop?

Cheers,

Lotje

lvanderlinden

Also, this discussion sounds useful:

• https://forum.cogsci.nl/discussion/3179/sampling-a-nested-loop-without-replacements

VictorVarela

Hi @lvanderlinden, on Block_loop I pretty much have 1 column containing 100 images (2 classes of objects) and a second presentation factor... it is a 4x2x2 design...

the break if option has: ([count_PresentImage]+1) % 20 == 0 and [count_PresentImage] > 0

lvanderlinden

Hi @VictorVarela

Did you also try using the "resume after break" option? If you upload your experiment we can give a more targeted response.

Cheers,

Lotje

VictorVarela

Yes @lvanderlinden, the resume after break worked great! However, I still have conditions that I don't want to repeat... such as:

|Image_to_show | Condition |

| Image1 | X |

| Image1 | Y |

When I check "resume after break" I still have these 2 Image1 being presented and ideally I need just one...

Thanks for everything, you are helping me a lot!

Cheers,

V

VictorVarela

@lvanderlinden It is working GREAT!

I managed to make it to work properly, thank you so much!