|
|
|
Junior Member
 
Group: Forum Members
Last Login: 10/17/2007 12:04:54 PM
Posts: 10,
Visits: 15
|
|
I am trying to create an experiment with the following design: There are two stimuli (S1 and S2) presented on each trial. S1 is always presented first, on a slide called SlideS1. S2 is presented after a variable stimulus onset asynchrony (SOA) on a separate transparent slide called SlideS2. Visually, subjects would see S1 appear onscreen, then after the SOA, S2 would also appear onscreen. I want to record a response to S1 and have no response given to S2.
The issue is that the response to S1 could occur during the SOA (while SlideS1 is still up) or after the SOA (when SlideS2 has replaced SlideS1). If the response occurs during the SOA, then I don't want SlideS2 presented; I want to skip it and go to the end of the trial. However, if a response doesn't occur during the SOA, then I want SlideS2 presented and I want the response to terminate SlideS2, ending the trial. Regardless of whether the response occurs during or after the SOA, I want to be able to record/calculate the response time from the onset of S1 to the response.
For anyone familiar with dual-task procedures, I basically want to set up a PRP procedure that has no response to S2, but where the response to S1 can occur before or after S2 has been presented, with the response terminating the trial.
The only possible solution that comes to mind is to set up SlideS1 such that its duration is equal to the SOA and a response can be recorded. When a response is given or the SOA duration is reached, the slide terminates. Then, there could be an inline script that determines whether a response occurred to SlideS1. If there was a response, then skip SlideS2 and go to the end of the trial. If there was no response, then present SlideS2 and set it up such that a response can be recorded that terminates the slide. For a response occurring during the SOA, response time would equal the response time recorded for SlideS1. For a response occurring after the SOA, response time would equal the SOA + the time recorded for SlideS2 (although I'd probably do the calculation using the computer timestamps for SlideS1 onset and SlideS2 offset, just in case executing the inline script adds a timing delay). I think this would work, except for very rare circumstances when a subject tries to make a response during the execution of the inline script (that is, in-between the slides that allow recording of a response). However, my knowledge of E-Basic is minimal and I don't know how to write the inline script that I've described.
I would appreciate any help with my proposed solution or with a different solution that accomplishes the goals I've outlined above. Thanks!
|
|
|
|
|
Forum MVP
Group: Administrators
Last Login: Yesterday @ 5:00:06 PM
Posts: 569,
Visits: 1,238
|
|
| You should be able to accomplish what you want with zero script. 1) Set the duration of S1 to how long you want S1 to appear on screen
2) In the keyboard/mouse input mask in duration/input, set its time limit to the maximum duration of the entire trial.
3) Set the end resp action to Jump
4) In the Label field, enter the name of a Label you want to jump to (i.e. Label1, EndOfTrial, etc)
5) Drop a Label object onto the Procedure after S2. Name it the same as you did in step 4 The NestingRT and NestingXRT perform these same operations. -Brandon
|
|
|
|
|
Junior Member
Group: Forum Members
Last Login: 10/17/2007 12:04:54 PM
Posts: 10,
Visits: 15
|
|
Brandon,
It worked beautifully! Thank you very much.
Out of curiosity, what are NestingRT and NestingXRT?
|
|
|
|
|
Forum MVP
Group: Administrators
Last Login: Yesterday @ 5:00:06 PM
Posts: 569,
Visits: 1,238
|
|
| They are one of the handful of samples included with the E-Prime installation and are located under the My Experiments\Samples folder. -Brandon
|
|
|
|
