Recording Real Time Responses

Dr. Dave Hairston dave.hairston at gmail.com
Thu Oct 16 15:04:37 UTC 2008


The method that David describes is exactly what I have been doin gfor
years with very good success.
Simply, what you need is a video card with two outtputs ("Dual-head").
Almost any card will do this nowadays; I'm partial to nVidia myself.
But anyhow, from that card, run 1 of the two lines itno a video
splitter box, so that you have 1 line in, 2 lines out... now you have
3 monitors, and 2 of them show the same thing. CAUTION - get a good
splitter with it's own power supply, the cheap stuff gives terrible
images.
Now place 1 of the "cloned" onitors in teh room with your subject, and
the other two outside in your "control room" or whatever.

E-Prime will automatically run the paradigm on the monitor that is
designated as "primary" in Windows... so set your cloned monitor to
this one, and move your E-Editor window to teh other one (I call this
the "experimenter's window" b/c teh usbject now cannot see it!).
Now you can see the Debugger window WHILE YOUR SCIPT IS RUNNING  and
your subject cannot... cool...

Just use very simple code after the response recording object to
report back the .RT or .ACC status after each trial; for example the
line:

debug.print Response. Acc & "  " Response. RT

will print out "1  345" or similar after each response.

>>Why would you want to do this???

Well, sometimes you need to know how your subjects are doing on-line;
perhaps they are in training and you wish to ensure they know what
they are doing.
In my case, I'm having usbjects do an adaptive staircase procedure...
and as we all know, staircases are notoriously flaky... and if people
get off track, it throwsteh whole procedure out of whack. So, I watch
their progress trial-by-trial to be sure they're progressing as
expected.

Hope that helps!!

Dave

P.s. - in theory, I believe EP 2.0 is supposed to support multiple
monitors. If this is the case, one could have it report status
directly to teh 1nd monitor which only teh experimenter can see, and
avoid the whole debugger window bit.....
On Oct 15, 11:08 am, "David Vinson" <d.vin... at ucl.ac.uk> wrote:
> > Speechy wrote:
> >> Is there a way that I can record participants' responses and their RTs
> >> while the subject is performing the task without sitting right beside
> >> them and without them seeing any type of feedback on accuracy or RT?
> >> For example, is there a way that the participant can complete a task
> >> on one computer (without any visual feedback) but I can see his/her
> >> responses and the RT for each trial on a different monitor in real
> >> time?
>
> It was once possible (v.1) to do this on a single machine using the debug
> window displayed on a second monitor. Inline code could be used to display
> relevant content to the debug window (Debug.Print as I vaguely recall),
> e.g. displaying the correct answer so the experimenter could see it.
>
> I used this on a few occasions where I wanted to do some real-time scoring
> of spoken responses, where offline scoring would not have been sufficient,
> e.g. signaling that speech errors of certain kinds had occurred and
> therefore a trial must be repeated later.  The subject had the button box
> and microphone (for voice relay) and I had a keyboard to signal "error"
> during an intertrial period, unbeknownst to the subject.
>
> I too am not sure why you would want to verify accuracy and RT by hand!
>
> david

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