I am trying to randomize the onset (stimulustimes) of the stimulus using this syntax, but it seems not working.

<trial time>
/ ontrialbegin = [clear(trial.time.stimulustimes]
/ ontrialbegin = [setitem(trial.time.stimulustimes,shape.targetdot,list.targetduration.nextvalue)]
/ stimulustimes = [1=fixation;2000=targetdot]
/ timeout = 2900
</trial>
Is there a way to fix this?
Thank you.

Hi, Dave.
It is possible to let this random value drawn following a normal distribution with a certain fixed mean and standard deviation, say, 2000 and 40? So the timeout stop approximately 68% times within 2000+_40.
ontrialbegin = [values.randomduration = round(rand(10,2999))]
Best,
Nakayama

Thank you for your advice, Dave.
Best,
nakayama 

You should use either /timeout or /trialduration, set to a random value below 3 seconds.

<values>
/ randomduration = 0
</values>

<sound mysound>
/ items = ("threeseconds.wav")
/ playthrough = false
</sound>

<trial sometrial>
/ ontrialbegin = [values.randomduration = round(rand(10,2999))]
/ stimulusframes = [1=mysound]
/ validresponse = (0)
/ timeout = values.randomduration
</trial>

There is no other way to "stop" a sound once it's started playing.

(*instead of using Timeout)