dear ethan
you wrote:
appropriate for 2 alternative forced choice (2afc). I suppose you are
using a yes-no paradigm, with a psychometric function running from 0.0 to
1.0. In that case, in line 45 change the guessing rate "gamma=0.5;" to
"gamma=0.0;" or whatever you think is appropriate.
stimulus intensity by copying QuestSimulate and changing the last line
from
"response=interp1(q.x2,q.p2,t) > rand(1);"
to just "response=interp1(q.x2,q.p2,t);"
I recommend log scaling of the stimulus axis. Use MATLAB's SEMILOGX
command.
you describe.
minimal length MATLAB program that exhibits the bug?
best
denis
p.s. nice to see you at ARVO.
you wrote:
>I am implementing QUEST to do a simple Muller-Lyer illusiongreat
>experiment as a lab for a class.
>
>I basically just modified QuestDemo.m. Once I'm done I'd be
>happy to share it for those who want to demo the measurement
>of the illusion or see how I was able to get QUEST to work.
>But I have a few miscellaneous questions:The demo uses a psychometric function that goes from 0.5 to 1.0, which is
>
>I would like to get the 50% threshold not the default 82%
>threshold used in the Demo. Choosing pThreshold=0.50
>causes an out of range error so I have been using 0.51 which
>looks like it gives reasonable results (a control line length
>comparison (no fins) gives good results) for this value. I would
>like to confirm that what I'm doing is OK.
appropriate for 2 alternative forced choice (2afc). I suppose you are
using a yes-no paradigm, with a psychometric function running from 0.0 to
1.0. In that case, in line 45 change the guessing rate "gamma=0.5;" to
"gamma=0.0;" or whatever you think is appropriate.
>I would like to plot the psychometric function (the Weibull fn)It would be easy to create a function to return P as a function of
>based on the results. Any hints on how to do this? I am not sure
>of how to scale the stimulus axis.
stimulus intensity by copying QuestSimulate and changing the last line
from
"response=interp1(q.x2,q.p2,t) > rand(1);"
to just "response=interp1(q.x2,q.p2,t);"
I recommend log scaling of the stimulus axis. Use MATLAB's SEMILOGX
command.
>QuestBetaAnalysis does not seem to be fully implemented. Thatit's not fully implemented. i don't think you'll want it for the project
>is it has no output. Is there a reason for this.
you describe.
>I would like to use GetMouse instead of GetClicks so that I canwe were not aware of any problems with GetMouse. Could you submit a
>check the location of the cursor and change its appearance
>based on the position. However GetMouse doesn't work so well.
>I get multiple mouse clicks when I check the button. Any ideas
>on how I can get this to work better?
minimal length MATLAB program that exhibits the bug?
best
denis
p.s. nice to see you at ARVO.