Using EBasic

Tue Apr 19 08:01:51 UTC 2011

Hi Vera,

Now that "the proper pro's"  gave their opinion, I'd like to throw in
my 2 cents... your post reminded me of a thread on the pst user forums
not too long ago: http://support.pstnet.com/forum/Topic5031-23-1.aspx#bm5039
. This person wanted to change the background to isoluminant colors...
the solution I gave him is perhaps a bit of a detour, I later realized
that it's probably quite possible to generate rgb values and assign
them directly on to the slide object background instead of using a
canvas rectangle with the same dimensions as the display... in any
case: in his last post the guy sounded quite happy, which makes me
think that he might well have succeeded also in the isoluminance part
of his quest... you could try to e-mail him and ask him for advice.

best,

liw

On Apr 19, 8:01 am, Michiel Spape <Michiel.Sp... at nottingham.ac.uk>
wrote:
> Hi Vera, Lisa, list,
> Just to add to this: it might be worthwhile to just make a screenshot (print-screen, open mspaint, hit paste) and take whatever stimuli you want out of matlab/presentation/etc and use those just as images in e-prime. I imagine that working with E-Prime makes it easier to implement your study in an ERP paradigm. If you want to pursue that path, I don't think your real issue is with programming, because you *should* be able to create the stimuli, isoluminant and whatnot, in photoshop or such. Once you have those (and I'm expecting you don't need millions of different stimuli in an ERP design), it should be a breeze to use these then in E-Prime. The more techy way to go about this is indeed using matlab, though as far as i know, you can't tell matlab or such to just make "grayscale, low contrast, isoluminant". Once you know the formulae behind such descriptions, I believe it shouldn't be too hard to just use photoshop or anything else (I think psychophysics people might want to kill me for making this statement, however).
>
> Of course,  if you do wish to pursue the 'make visuals on the fly' sort of path, you might find it helpful to have a look at PsychoPy (developed around here), which I'm sure should be fairly easy to work with as well. It has functions predefined (I think) for gabor-type stimuli and all the basic ingredients of the field of visual cognition (and others). Since it works on PCs as well, I guess you could even run it, make the stimuli, hit print-screen and get the experiment to run in E-Prime anyway.
>
> Best,
> Mich
>
> ________________________________________
> From: e-prime at googlegroups.com [e-prime at googlegroups.com] On Behalf Of David McFarlane [mcfar... at msu.edu]
> Sent: 18 April 2011 20:23
> To: E-Prime
> Subject: Re: Using EBasic
>
> Lisa,
>
> As I recall, Presentation has some very nice high-level facilities
> for generating complex and dynamic visual stimuli on the fly.  By
> contrast, E-Prime has no such facilities.  EP can do some limited
> things with text, for anything else it usually just presents image,
> sound, or movie files.  But you can go beyond this with low-level
> E-Basic code, for that you  would make extensive use of the methods
> of the Canvas object -- see the Canvas topic in the online E-Basic
> Help.  To do this well you would probably want to make a bunch of
> custom subroutines or functions to recreate some of what Presentation
> did for you -- for more on making subroutines and functions, you
> might take a look at Chapter 4 of the User's Guide that came with
> E-Prime, and more particularly work through the classic "VBA for Dummies".
>
> Of course, you could just do this all back in Presentation, which you
> know already does this; or even better, do this all in MATLAB using
> the Psychophysics Toolbox, which has fantastic visual presentation support.
>
> On an off-topic digression, I just learned about a new free
> open-source cross-platform Python-based system called OpenSesame
> (http://www.cogsci.nl/software/opensesame).  Has anybody tried this,
> and can comment on how it stacks up against E-Prime or other products?
>
> -- David McFarlane, Professional Faultfinder
>
> At 4/16/2011 03:11 PM Saturday, Lisa Levinson wrote:
>
>
>
> >I am trying to replicate an event-related potential experiment that
> >investigated the development of the magnocellular and parvocellular
> >visual pathways. I am not looking to further study the development of
> >these pathways, rather their correlation with other behavioral
> >measures. The stims were originally programmed using the Presentation
> >software language. I have attempted to create modified versions of the
> >stims using Quark and Final Cut. I have generated the graphics and
> >imported them into E-Studio but the major issue I am having concerns
> >the parvocellular stim. If I can't control for luminance then I will
> >potentially be eliciting a response from the magnocellular pathway as
> >well.
>
> >Using EBasic I was wondering if it would be possible to create
> >"objects" such as a blue and green high frequency grating in which the
> >colors are isoluminant with the background and low spacial frequency
> >grayscale grating with a low luminance contrast. I have limited
> >programming experience but can work with others who know Visual Basic
> >for Applications. I am concerned though the psychophysical nature of
> >these stims will not work with EPrime.
>
> >Would greatly appreciate some input.
>
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