Combining two input recording images together to form mean accuracy

[Michiel Spape]

Hi,
Coincidentally, I'm just working on a stop-signal task at the moment! You might want to reconsider the part where you seem to need different procedures for different conditions, especially, as you later say, if you then also have different objects for different conditions. In general, it's a very good idea to manipulate psychological aspects whilst keeping physical properties equal (as Steven Luck would suggest) - I'd expand upon the concept by suggesting programming aspects may well be part of the physical (by which I do not condescend to say anything about metaphysics, by the way). Apart from such considerations, the other problem is that it is very easy to make mistakes in the almost inevitable complexity resulting from using different objects and procedures in different conditions.
I use, for example, the same procedure, and *all* objects whether I have GO, NO-GO, GO-STOP and even NO-GO-STOP (although I kicked that possibility out since it makes very little sense). That is, if you two of the same slides after one another:

Slide1 (primary task), duration of which is stop-signal delay, time limit, something like 1000)
Slide2 (stop-signal, if any), shows the same arrow as Slide1 (it refers to same attribute), and has whatever duration

Then, the 'clever' bit is that the responses are *always* recorded in Slide1 (which makes it easier in E-DataAid), and, if there's no stop signal, slide2 just refers to same attribute, and the subject will never notice there are actually two arrows, rather than one.

Other than that, if you must, I'd suggest just a little bit of inline. Basically, you check for conditions, and calculate the mean accuracy. For example, if you made a global variable (alt+5, user script, dim LeftArrowNumberAccurate), just add an inline at the end of the trial (if c.GetAttrib("ArrowDirection") = "Left" and Slide1.ACC = 1 then LeftArrowNumberAccurate = LeftArrowNumberAccurate + 1). Then, at the end of a block, you show a text display with the accurate number (or percentage). I think all that is explained at length at the end of the infamous E-Primer: http://www.psychology.nottingham.ac.uk/staff/lpzmmas/about_me.htm (under books).

As for your other question:
"My other question pertains to the E-dataid file. I am curious if there is a way to combine all three procedures to report their reaction times for each trial under one column. Instead of a separate column for each (and a lot of NULL entries)."

What's wrong with using procedure(trial, subtrial, block, depending on the structure of your experiment) in column? Remember to filter out NULLS, they are annoying. As for two separate images, and actually, in general, I always store dependent variables in one and the same column, Y_RT (and Y_ACC, etc), just for clarity. To do this, just do the following inline at the end of your trial(s):
c.SetAttrib "Y_RT", Slide1.RT
so, if you have two images for two procedures, just store it in the same attribute and the result will be much more readable.
Best,
Mich

Michiel Spapé
Research Fellow
Perception & Action group
University of Nottingham
School of Psychology


-----Original Message-----
From: e-prime at googlegroups.com [mailto:e-prime at googlegroups.com] On Behalf Of Daniel
Sent: 28 July 2010 21:02
To: E-Prime
Subject: Combining two input recording images together to form mean accuracy

Hey,

I have programmed a stop-signal paradigm and the only way I could
figure out how to have a left red arrow (STOP) appear after a left
green arrow and a right red arrow appear after a right green arrow was
to have two difference procedures. Total I have 3 procedures. One
presents a green arrow and the person responds to the direction of the
arrow. The second procedure a green left arrow appears and after a
designated period of time this arrow turns red, if the arrow turns red
the person must withhold a response. This is the same for the right
green/red arrow, which is the third procedure. Of course they are all
randomized so there is a 70% chance a green arrow will appear and stay
green, 15% chance for a left green to appear and turn red, 15% chance
for a right green to appear and turn red.

I would like to have feedback displays after every block, that only
reports the specific data for that block, and I know how to set this
up. My question itself regards collapsing across right and left stop
accuracies. I would like to combine procedure 2 and 3 to report their
combined accuracy.

My other question pertains to the E-dataid file. I am curious if there
is a way to combine all three procedures to report their reaction
times for each trial under one column. Instead of a separate column
for each (and a lot of NULL entries). Note: I have to have seperate
names for the images the record the responses since two of them have
specific images that must be presented. I know I can do this when I
create a syntax file to strip them down and recombine them in to spss.
But, it would be easier to have it already done for me.

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