scoring a nonresponse as a correct answer

[Jim]

Ben: I mispoke, only the stimulus is recording responses and it has a
response window duration of 1250ms just as you said. On this
particular task, I don't want to mess with pre-release because the
scanner paradigm has already been used/validated by someone in my lab
with 100ms prerelease on every object. I just want to figure out how
to score non-response without inline code (the person who used the
task before me did not log responses).

Michiel: I'm not following you, so I will give more detail about the
procedure of the task and maybe this will answer your question. Each
trial presents a letter in the middle of a black screen for 250ms
(with a response window duration of 1250ms) followed by a black screen
(with no letter) for 1000ms.

Thanks!
Jim

On Feb 23, 11:21 am, ben robinson <baltimore.... at gmail.com> wrote:
> you say both your stim and the subsequent blank screen objects are recording
> responses?
> i would recommend that you set the stim to terminate after 250ms without
> prerelease, set the response window duration to 1250 ms, and do all the
> prerelease stuff at the end of your 1000 ms blank screen without expecting
> the blank screen to record any responses.  the benefit to using only a
> single object to collect responses is mainly that it gives you a cleaner
> data file - you only need to look within a single column to see all the
> responses or non-responses, rather than look at multiple columns belonging
> to multiple E-Objects (stim and blank).  that would be my preference...
>
>
>
> On Tue, Feb 23, 2010 at 11:00 AM, Jim <jjprisciand... at gmail.com> wrote:
> > Ben: Thanks, this is a creative solution. However, as per David's
> > response, it seems like there is something wrong with my task and that
> > it should be able to correctly score nonresponses without inline code.
>
> > David:
> > "I myself have used a blank [Correct] to score the accuracy of
> > no-response trials (where the absence of a response is correct and
> > any other response is incorrect) and that worked fine for me."
>
> > By reading the description above of my experiment, do you have any
> > leads as to what might be causing the no-response trials to be
> > incorrectly scored? I'm stumped.
>
> > "For instance, if you do not use the .ACC within the trial
> > itself (only to log it) and know the response will come before the
> > onset of the final object in trial Procedure, then you can safely use
> > PreRelease with abandon and then use inline code after the final
> > object to score the .ACC if needed."
>
> > Unfortunately, I don't think this will be helpful because the final
> > object in the trial procedure is still logging participants responses.
> > For this particular experiement, the trial procedure consists of a
> > letter (250ms), and subsequently a blank screen (1000ms); participants
> > responses are logged during both of these objects. For my other
> > experiments, the inline scoring code is used in the trial itself.
>
> > One related question/clarification: I am assuming that if there is no
> > inline scoring code that prerelease doesn't interfere with data
> > logging. Is this a correct assumption?
>
> > Thanks,
> > Jim
>
> > On Feb 22, 5:52 pm, David McFarlane <mcfar... at msu.edu> wrote:
> > > Jim,
>
> > > First, your earlier designed used what I call "multiple correct
> > > response targets".  By way of background, if you search this Group
> > > using terms like that then you will find where we have discussed
> > > several approaches to that.
>
> > > Second, I wonder if something else is going on in your program?  I
> > > myself have used a blank [Correct] to score the accuracy of
> > > no-response trials (where the absence of a response is correct and
> > > any other response is incorrect) and that worked fine for me.  It
> > > should just work for you.
>
> > > Third, you might want to study Chapter 3 further to better understand
> > > the intricacies of PreRelease.  Sadly, PST does not do a very good
> > > job of explaining it, and in fact the whole PreRelease mechanism
> > > provides much more granularity than users need or want (should be
> > > just on or off -- whenever I use PreRelease I just set it to some
> > > arbitrarily large value, often larger than the Duration, with no ill
> > > effects).  For instance, if you do not use the .ACC within the trial
> > > itself (only to log it) and know the response will come before the
> > > onset of the final object in trial Procedure, then you can safely use
> > > PreRelease with abandon and then use inline code after the final
> > > object to score the .ACC if needed.
>
> > > Fourth, whenever I teach E-Prime for fMRI, I first briefly explain
> > > the difference between Event and Cumulative timing.  Then I just lay
> > > down the law and tell students, for fMRI, just make things easy and
> > > set *every* object to Cumulative timing!!  Yes, I know that is
> > > excessive, but I have yet to find a case where Cumulative timing
> > > creates a problem, whereas Event timing is known to create problems
> > > in several contexts.  If it were up to me I would just make
> > > Cumulative the default and then only allow users to choose Event mode
> > > if they think it really applies to their study (back when I wrote
> > > everything in C I did everything in what E-Prime calls "Cumulative"
> > > timing mode, it just seemed cleaner and took no real programming effort).
>
> > > -- David McFarlane, Professional Faultfinder
>
> > > At 2/22/2010 11:17 AM Monday, you wrote:
>
> > > >i think you'll need to use an inline to do this, but i also think
> > > >you can mostly avoid the complications introduced by using the
> > prerelease.
> > > >here's what i would do:
>
> > > >put your inline after the 1000 ms blank screen, knowing that the
> > > >inline code may be read as early as 900 ms into the blank screen's
> > > >duration (and only 1150 ms after onset of your letter stimulus).
> > > >the script in the inline would be something like this:
> > > >Do
> > > >Loop Until (Clock.Read - LetterStimulus.OnsetTime) < (1250 -
> > > >Display.RefreshDurationStats.Mean)
> > > >If LetterStimulus.RESP = "" And c.GetAttrib("Stim") = "X" Then
> > > >LetterStimulus.ACC = 1
>
> > > >that Do...Loop will loop continuously until there is less than a
> > > >single screen refresh's worth of milliseconds remaining in the
> > > >LetterStimulus's response window, at which point the script will
> > > >kick out of the Do...Loop, check to see if there was no response,
> > > >and if no response and if 'X' then assign an accuracy of '1' to the
> > > >LetterStimulus object.
>
> > > >how's that?
>
> > > >ben
>
> > > >On Mon, Feb 22, 2010 at 11:01 AM, Jim
> > > ><<mailto:jjprisciand... at gmail.com>jjprisciand... at gmail.com> wrote:
> > > >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- Hide quoted text -
>
> > > - Show quoted text -
>
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