modulo and varied predictability of cue location
So, I want my variable arrow_cue (my jpeg) to appear every 20th trial. So, I am using a modulo (suggested to me in another forum). Something along the lines of: ([count_somename])+1)%20 = 0. But I know this needs to be put within an if-else statement, which I am not sure how to do. I want to somehow say that if the arrow cue has appeared in the last 20 trials, do not appear again on the next trial.
In addition, I have variables "valid_pos" and "invalid_pos" for valid and invalid positions. I want my arrow cue to be predictive of where the target will be for 16 out of the 20 trials.

Comments
Hi,
Did you have a look on the beginner's tutorial? It describes a cueing paradigm that is quite similar to yours. If you add 4 times more valid trials than invalid trials to the loop table (just by adding lines), 80% of your trials will be valid and the rest invalid.
If you click on the sequence in which your trial loop is presented, you will see that there is a
run iffield. If you put your condition in that field, your loop is only arrow cue will be presented only every 20th trial.Does this make sense?
Eduard