Correcting RTs for positive SOAs (picture word interference)

[Tony Zuccolotto]

...just to be complete you may also want to update the Wait.RTTime
property as well, e.g. x.RT indicates the # of msec from the onset of
the stimulus and x.RTTime indicates the # of msec that have elapsed
since the beginning of the experiment.

Tony
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> -----Original Message-----
> From: Susan Campbell [mailto:susanc at andrew.cmu.edu]
> Sent: Monday, November 25, 2002 4:00 PM
> To: David Vinson
> Cc: eprime
> Subject: Re: Correcting RTs for positive SOAs (picture word
interference)
> 
> It is possible to correct the RT immediately after the response each
time,
> and it appears to be relatively straightforward.
> 
> After the Wait object is presented, you could do the following in an
> Inline:
> Get the SOA
> If the SOA is positive,
> Wait.RT = Wait.RT + SOA
> 
> For an example of something similar, you can look at the script from
> http://step.psy.cmu.edu/scripts/Attention/Pashler1992.html
> 
> Hope this helps,
> Susan Campbell
> STEP Project
> Carnegie Mellon
> 
> On Mon, 25 Nov 2002, David Vinson wrote:
> 
> > Hello all,
> >
> > I am wondering if anyone can help me out with a small design
problem.
> We
> > are carrying out a picture-word interference experiment, and are
> > manipulating SOA between the picture and word displayed.  We always
want
> to
> > measure RT from the picture onset.
> >
> > If SOA < 0, the word is displayed before the picture, if SOA > 0,
the
> word
> > is displayed after the picture.  We currently use conditional
branching
> to
> > determine the order in which these items are displayed, and collect
RTs
> > from an empty "Wait" object that immediately follows the
last-presented
> object:
> >
> > (SOA < 0)
> > Word display for [-SOA] milliseconds
> > Picture display
> > "Wait" object until response is made
> >
> > (SOA > 0)
> > Picture display for [SOA] milliseconds
> > Word display
> > "Wait" object until response is made
> >
> > The problem is in the latter condition: RTs measured for the "Wait"
> object
> > underestimate the picture response latencies by (SOA) milliseconds.
Is
> > there a way to automatically correct these RTs in the datafile using
an
> > inline object?  Or alternatively, is there an easy way to create a
new
> > variable (e.g. CorrectedRT) which is logged to the datafile?
> >
> > Thanks,
> > David Vinson
> > Dept of Psychology, University College London
> >
> >
> >
> >
>