scoring a nonresponse as a correct answer

[Jim]

Hello forum,

I sent this question to e-prime support last week; unfortunately, they
are experiencing high volume and have been taking a long time to get
back to my requests. They are time sensitive, so I was hoping the
forum might have some ideas.

I'm working with an e-prime experiment where participants are asked to
press a button ("7") whenever they see a letter except for "X" (at
which point they are asked to withold a response). I have a column in
my task list "CorrectAnswerL" which states "7" for any letter (another
column in the task list) other than X; CorrectAnswerL is blank for
trials with "X"s. In the procedure associated with that list, the
stimulus "LetterPresentation" has [CorrectAnswerL] listed in the
"Correct" blank in the "Duration/Input" tab. When I run the task,
nonresponses are not scored as correct for X trials (that is,
LetterPresentation.ACC = 0).

I previously had the task running with an inline script following the
stimulus and a blank pane "ISI" which stated:

If LetterPresentation.RESP = c.GetAttrib ("CorrectAnswerR") OR
LetterPresentation.RESP = c.GetAttrib ("CorrectAnswerL") Then
LetterPresentation.ACC = 1
End If

At this time there were two correct responses which is why there is an
additional "correctanswer" attribute. This is no longer the case, and
I want to remove the inline code. However, when I was using this code,
nonresponses were scored as correct for X trials. Please let me know
how I can have nonresponses scored as correct for X trials without
using inline code.

As an aside, I removed the inline code because I am concerned that it
will be executed too early. Each trial consists of the presentation of
a letter (250ms), and subsequently a blank screen (1000ms)- both
objects have a 100ms prerelease. Once the letter is presented,
participants have until the end of the blank screen (1250ms later) to
make a response. I prevously had the inline script following the blank
screen object ("ISI"). I've been reading the critical timing chapter
of the eprime manual which made me concerned that if participants made
a response between 1150 and 1250ms their response will not be scored
with inline code because of the 100ms prerelease on the blank screen.
A complicating factor, is that I can't change the timing of the task
whatsoever, it has an associated fMRI program that it must be tightly
timed with.

Thanks,
Jim

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