dual task reaction times

[A. de Ruijter]

Dear all,

I have an experiment where I have a vocal response to a simple
multiplication (eg. 7*8) and a keyboard response to a red circle (and
not to a green or yellow one). These are presented on the same slide.
My problem is that only the response that is made first gets logged
with its reaction time and other data. Is there a way to log both of
the reaction times?

Greetings,
Alex de Ruijter

[David McFarlane]

Alex,

One thought, start with a Wait object with Duration 0, have it get
the voice response with an appropriate Time Limit, and set End Action
to (none). Follow that with your slide object, and have the slide
get the keyboard response for the red circle, again with an
appropriate Time Limit. One problem, you will have to decide which
if either of these responses is allowed to terminate the slide,
probably best to let the slide just time out and set End Action to
(none) for all inputs.

Also, if you browse the PST Downloads area you may find that they
have a program to demonstrate this.

-- David McFarlane, Professional Faultfinder

[A. de Ruijter]

Thanks so much, will try this on monday.

Alex

[Elizabeth M]

Many of the posts on here and the sample experiment demonstrating a dual task experiment, require that the response for the secondary task be on a separate slide. Is it possible to program an E-prime experiment where the the secondary task appears on the current slide with the primary task? 

In my experiment, I have participants reading descriptions and dragging and dropping the matching picture into the appropriate goals (all on one slide).  I would like to also have a secondary task where the participant must also respond on a RT box with a key press when a red asterisk appears on the slide.  The asterisk appearance will occur multiple times, at random while the participant is performing the primary task.  The asterisk will always appear in the same place, but it must occur on the slide as if it changes from the current screen to another, it will be quite obvious that the asterisk has appeared and it is time to press the button.

Any advice? 

[David McFarlane]

Well... Simply to overlay one visual stimulus over others, yes you
may do that with judicious use of stimulus Frame and BackStyle
properties. And you may use a number of techniques to gather
separate response input streams.

The real challenge comes when you want to provide multiple concurrent
and erratic stimulus streams, which is what you describe here. I
think E-Prime poorly suited to this, but you might ask PST for their
opinion. In another era I did something much like this using C on a
DOS platform, in that case I constructed a global schedule for all
timed events, and then made my own event loop that handled each input
while checking the schedule to handle scheduled events. I am still
rather proud of that particular project.

You might still find MATLAB, PsychoPy, or even standard computer
languages such as C, C++, C#, or Python better suited to this task.

-----
David McFarlane
E-Prime training
online: http://psychology.msu.edu/Workshops_Courses/eprime.aspx
Twitter: @EPrimeMaster (https://twitter.com/EPrimeMaster)

/----
Stock reminder: 1) I do not work for PST. 2) You may reach PST's
trained staff (and other support facilities) at
https://support.pstnet.com . 3) If you do get an answer from PST
staff, please extend the courtesy of posting their reply back here
for the sake of others.
\----

[David McFarlane]

Oh, I meant to add that, in principle, you could indeed do in E-Prime
what I did with C (program your own event loop, etc.). But again, I
think E-Prime poorly suited to that type of programming.

-- David McFarlane