Millisecond Forums

Hi all,

Just a little thing - I have a reading task on the go with intermittent probes and want to randomise the time it takes for them to appear.

The part of the script concerned is:

<trial readingtrialHAT>
/ ontrialend = [if (trial.readingtrialHAT.response==205 && values.pagenumber < values.npages) values.pagenumber +=1;
  if (trial.readingtrialHAT.response==203 && values.pagenumber > 1) values.pagenumber -= 1;]
/ ontrialend = [values.timeuntilprobe -= trial.readingtrialHAT.latency]
/ stimulusframes = [1=pagetext]
/ validresponse = (203, 205, 57)
/ timeout = values.timeuntilprobe
/ branch = [if (trial.readingtrialHAT.response == 0) trial.HATtrial else trial.readingtrialHAT]
</trial>

<trial HATtrial>
/ ontrialend = [values.probenumber += 1;
  values.timeuntilprobe = values.probeinterval]
/ stimulusframes = [1=clearscreen, probepromptHAT; 2=picture.hat]
/ correctresponse = ("y", "n")
/ validresponse = ("y", "n")
/ branch = [trial.readingtrialHAT]
</trial>

<values>
/ npages = 20
/ pagenumber = 1
/ probeinterval = 10000
/ timeuntilprobe = values.probeinterval
/ nprobes = 8
/ probenumber = 0
/ completed = 0
</values>

I thought changing '10000' in /probeinterval to replace(30000,40000,50000,60000) would do the trick- which is the effect I want- but it seems to just select the last value and use it consistently.

Any ideas as to what I'm missing?

Thanks!