Blocks and Trials; Trials and Blocks

Hi - I have an experiment with 8 different blocks that will correspond to 8 different groups of subjects. There are 24 different trials that represent 24 different stories. A trial has about 11 or 12 different events that correspond to each trial.
Depending on which group the participant is in (block1,2,3,…8) one of the events will be different. In other words, for block 1, trial 1, I would include events 1,2,4,11, & 12. Then for block 2, trial 1, I will include event 1,2,6,11,12.

My question is…is there a way to program each block to correpsond to all the same trials, which will then correspond to slightly different events depending on which block. When I do this now, if I change what events correspond to a trial in block 3, it will change what events correspond to what trials in every other block.

I’m sorry if this is not clear! Please help!

Thank you so much


There are a couple of ways you can do this, but they may not be much help.

  1. The traditional method is to create more than 24 trials and put the appropriate trials in the different blocks. For example, for block 1, trial 1, you would physically have Trial 1a, which includes events 1,2,4,11 & 12. For block 2, it’s Trial 1b, which has events 1,2,6,11, & 12. Depending on your setup, you may wind up creating 24 different trials for each of the eight blocks. This shouldn’t be too bad, though. Once you have Trial 1a set up, you can copy and paste it a few times and then just tweak the event selection.

  2. Depending on your requirements, you may be able to use Macros (at the block level) to do what you want. This won’t help any if you are looking for something to be different in the middle of the trial, but it can insert differences between trials.

My suspicion is that #1 is probably what you’ll wind up needing to do.