trial limit

[bisserai]

Hi FF team,
I'm getting an error that my blocks are exceeding the number of trials allowed. The message says i have 329 trials when only 150 are allowed, but i'm not sure how this is calculated, because i thought i had only 36 trials per block...? I assume this has to do with the following piece of code, as 36 trials times 9 trial templates per trial is 324 (and then some additional cover and end trials i guess). The reason why i have so many "BS" templates is because when i was using durations of stimuli vs trials to get a blank screen this was messing with the trials proceeding properly and so adding a blank screen in between instead worked much better.

Code:

"BL1": {
          "trial_templates": ["BS","Vprime1","BS", "prime1","BS", "Vtarget1","BS", "target1", "catch"],
          "pattern": {"order": "alternate_random"},
          "fetching_point": true,
          "cover_trials": ["fixation"],
          "end_trials": ["break"]
        },

The issue is this means i'll have to more than half the amount of actual trials i have per block, which i really would rather not do and so i was wondering if this trial limit is something that can potentially be increased? 

Thanks,
bissera

[Ting]

Hi Bissera,

Inside the block BL1, you can add:

Code:

max_trials: 400

where 400 is the max number of allowed trials. We keep this feature on a need-to-know basis because you can easily imagine one may accidentally build a study with 1000+ trials in a block, and that may crash FF servers entirely. So use this feature responsibly please? Thanks!

[bisserai]

Hi Ting,

Thanks a lot! I will use only when really necessary, i can imagine the mess no limits could create...

Best,
bissera

[Ting]

You are most welcome, Bissera!

For everyone else reading this, we'll cap this parameter at 500 in early May, meaning that 500 trials will be a hard upper limit per block.