QUEST question

Hello,

I am using the psychtoolbox to test orientation discrimination in
noise, and have implemented the QUEST staircase for threshold
estimation. I would like to set my prior threshold estimate for QUEST
at the beginning of each run to be a multiple of the predicted
threshold (e.g. tGuess = 2x predicted threshold). However, this means
that under conditions where a higher threshold is predicted, the
staircase doesn't settle onto a value until much later in the run.

Is there a way that I can increase the 'step-size' at the beginning
of
each run proportionally?

Thanks in Advance,

Nicole Anderson
McMaster University