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Thanks to everyone who responded to my question about measuring RT from a
point within a wav file. Several practical suggestions were made,
and I will give them a try. Below are my question and the
responses, for those who are interested.<br>
Carol<br>
<dl><i>
<dd>I am collecting response times to sound files. In the
experiment I am working on, the subjects' task is to listen to a sentence
and press one button if it is grammatically correct, and another button
if it is incorrect (I'm using the PST Serial Response Box). I have
this experiment working all right, but I would like to refine it: I
would like to measure the RT from the onset of a crucial word in the
sentence, rather than from the onset of the sound file. Is there a
way to either a) place a marker in the sound file that will tell Eprime
to start measuring RT? or b) tell Eprime to start measuring RT at a
certain point , i.e., file onset + xxx ms? The crucial point is
different for each sentence.<br><br>
</i>
</dl>#1<br>
Is making each word a separate object/event out of the question?
Otherwise<br>
this seems like to most straight forward attempt.<br>
Good Luck<br>
Dan<br><br>
#2<br>
Here's a way that would probably work. In a list<br>
object, have one attribute that contains the name of<br>
the sound file for each trial, and another that<br>
contains the offset of the crucial time in<br>
milliseconds for that file. Then set your sound<br>
object to have duration equal to the crucial time,<br>
making sure that the sound object is configured to<br>
continue playing the sound after the sound object<br>
terminates. Then have a blank screen (i.e. a blank<br>
text object) that follows the sound object, with<br>
user input enabled.<br><br>
<br>
Tom Johnstone, Ph.D.<br>
Keck Laboratory for Functional Brain Imaging and<br>
Behavior<br>
Waisman Center<br>
University of Wisconsin-Madison<br><br>
#3 (David Fencsik and Tony Zuccolotto came up with essentially the
same solution)<br>
I assume you have a list object that specifies which sound file to
use<br>
on each trial. If this is the case, then you can add a column to
the<br>
list object that specifies the time from the onset of the sound to
the<br>
onset of the crucial word. After the response is collected, you
could<br>
create a script that looks up the time and subtracts it from the
RT.<br>
Or, to be safe, you could create a new attribute that stores the RT<br>
minus the time delay.<br><br>
David<br><br>
<i>***********<br>
</i>There is no way currently in E-Prime to automatically adjust an RT
based<br>
on the offset of a word in the file.<br><br>
To do this you would probably have to list the word offsets as an<br>
attribute and then insert some script at the end of the trial to
adjust<br>
the RT, e.g. <br><br>
<x-tab> </x-tab>If
Stimulus.RT > c.GetAttrib( "WordOffset") Then<br>
<x-tab> </x-tab><x-tab> </x-tab>Stimulus.RT
= Stimulus.RT - c.GetAttrib("WordOffset")<br>
<x-tab> </x-tab>Else<br>
<x-tab> </x-tab><x-tab> </x-tab>'
Responded before the word was presented<br>
<x-tab> </x-tab><x-tab> </x-tab>Stimulus.RT
= 0<br>
<x-tab> </x-tab>End
If<br><br>
Hope that helps.<br><br>
Tony<br><br>
*** DISCLAIMER: ALL VIEWS EXPRESSED ARE MY OWN AND DO NOT
NECESSARILY<br>
REFLECT THOSE OF PSYCHOLOGY SOFTWARE TOOLS *** <br><br>
<br><br>
<x-sigsep><p></x-sigsep>
++++++++++++++++++++++++++++<br>
Carol Miller, Ph.D.<br>
Dept. of Communication Sciences & Disorders<br>
Penn State University<br>
115-B Moore Building<br>
(814) 865-6213<br>
cam47@psu.edu<br>
++++++++++++++++++++++++++++</html>