Determining thresholds

[swa...@sheffield.ac.uk]

I'm designing a masked Stroop task and need to determine an appropriate threshold for each participant. I am trying to create a task which presents a stimulus in increasing intervals of 17ms (i.e. 17ms, 34ms etc.) until a participant can successfully identify the stimulus, at which point, the next stimulus will be presented (for 17ms etc.). Can anyone suggest any ways I can code this in E-Prime 2.0 please? Any help will be hugely appreciated!

[swa...@sheffield.ac.uk]

My experiment contained a loop where if the Participant responded incorrectly, they would repeat the trial (specified using a label called 'RepeatTrial'). David Nicholson of PST gave me the following feedback:

Use an Attribute reference for your Stimulus duration. You can add an InLine after RepeatTrial and set the default duration the InLine. You can call the Attribute something like StimDur. I would also create a Global Varible called nDur and set its default value (e.g. 17ms). You can set the default value of nDur in an InLine prior to RepeatTrial.

'before RepeatTrial
nDur = 17

'after RepeatTrial
c.SetAttrib "StimDur", nDur

Then increase it by 17ms each time it is ran (for example). To do this, you would change the Mouse Input 2 (Allowable 2) (this indicated an incorrect response) End Action to Terminate. Then add an InLine after the CaProcPostMask. If the InLine, you can use the following script:

If CAProcPostMost.RESP = "2" Then
  nDur = nDur + 17
  GoTo RepeatTrial
End If

Please see INFO: Declaring a global variable in User Script (Video How-To) and E-Prime How To: Advanced Attributes.