Millisecond Forums

You can't do this in the /stimulusframes attribute directly. Instead you need to work with the setstimulusframe and/or insertstimulusframe function(s). Details are available in the documentation.

However, it might be way easier to simply use different <trial> elements.

Edit: Here's a quick, basic example:

<values>
/ myvalue = 1
</values>

<block myblock>
/ trials = [1=mytrial]
</block>

<trial mytrial>
/ ontrialbegin = [if(values.myvalue==1){
    trial.mytrial.insertstimulusframe(text.b1,1);
    } else {
    trial.mytrial.insertstimulusframe(text.b2,1);
    }]
/ stimulustimes = [0=a,c]
/ ontrialend = [trial.mytrial.resetstimulusframes()]
/ validresponse = (57)
</trial>

<text a>
/ items = ("A")
/ position = (25%, 50%)
</text>

<text b1>
/ items = ("B1")
/ position = (50%, 50%)
</text>

<text b2>
/ items = ("B2")
/ position = (50%, 50%)
</text>

<text c>
/ items = ("C")
/ position = (75%, 50%)
</text>

Thanks, used set stimulus frames and that works.