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Junior Member
 
Group: Forum Members
Last Login: 10/17/2007 12:04:54 PM
Posts: 10,
Visits: 15
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Hello,
I am designing an experiment in which subjects must press one of three response keys on each trial. However, I do not want them to be able to repeat responses across consecutive trials. For example, if the keys are labeled A, B, and C, I want to be able to program E-Prime such that if the subject presses key A on trial n, he is ONLY able to press either key B or key C on trial n+1. If he presses key B on trial n+1, then he is only able to press either key A or key C on trial n+2, and so on...
I already have my program set up such that E-Prime logs the response on each trial and that the only allowable response keys are A, B, and C. However, I do not know how to restrict the allowable responses on a trial-by-trial basis in the manner described above.
Any help would be greatly appreciated, given that a cursory search of the E-Prime support website did not turn up anything that seemed helpful. Thanks!
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Forum MVP
Group: Administrators
Last Login: 1/5/2009 9:26:59 AM
Posts: 576,
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| There are a number of ways to implement this and here is one of them... 1) Dim a string variable in User script. Dim g_strLastResponse As String 2) Place an InLine as the last object in your procedure, with g_strLastResponse = Stimulus.RESP or whatever your Stimulus name is 3) Place an InLine as the first object in your procedure, use code similar to the following If g_strLastResponse = "a" Then c.SetAttrib "Allowable", "bc" If g_strLastResponse = "b" Then c.SetAttrib "Allowable", "ac" If g_strLastResponse = "c" Then c.SetAttrib "Allowable", "ab" 4) In the Allowable field for your Duration/Input Stimulus, enter [Allowable] -Brandon
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Junior Member
Group: Forum Members
Last Login: 10/17/2007 12:04:54 PM
Posts: 10,
Visits: 15
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Brandon,
Thank you very much for the clear and concise instructions. They worked perfectly--just what I wanted!
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