Millisecond Forums

Thank you Mr. Dave. The post is very helpful!

It is possible to do this, but it requires some trickery using the /isvalidresponse attribute: See e.g. here: https://www.millisecond.com/forums/FindPost15812.aspx 

You'd have to modify or extend that to record the latency property instead of or in addition to the response property.

Thank you Mr. Dave. This Syntax is very helpful! 
May I ask another question here? I wonder if I can let participants count the time by pressing one key (so that the counting behavior is measured by how many times they press the key) on the keyboard while they are being presented with stimulus.
Does any syntax allow me to do this? Could I record the temporal interval between each count?   
Thank you for your concern!
Best Regards,
Nakayama

This entirely depends on how your procedure is set up and how you define "lapsed".

In general, you don't repeat a <trial>, rather you repeat a given stimulus -- more precisely -- don't select a new stimulus.

Here's a simple example: Suppose you want to repeat a given stimulus if the participant's response latency is 2000 ms or greater. Then you do:

<values>
/ myvalue = 1
</values>

<text mytext>
/ items = ("A", "B", "C", "D")
/ select = values.myvalue
</text>

<list mylist>
/ poolsize = 4
</list>

<trial mytrial>
/ ontrialbegin = [if (trial.mytrial.latency < 2000) values.myvalue = list.mylist.nextindex]
/ stimulusframes = [1=mytext]
/ validresponse = (57)
/ branch = [if (trial.mytrial.latency >= 2000) trial.mytrial]
</trial>

<block myblock>
/ trials = [1-4 = mytrial]
</block>