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Psychophysical measurement technique - PEST?
- To: Multiple recipients of list AUDITORY <AUDITORY@xxxxxxxxxxxxx>
- Subject: Psychophysical measurement technique - PEST?
- From: Peter Marvit <marvit@xxxxxxxxxxxxxxxxxxxxxxx>
- Date: Sun, 28 Feb 1993 15:29:22 EST
- In-reply-to: Your message of "Thu, 25 Feb 93 11:37:11 EST." <9302251721.AA11439@cattell.psych.upenn.edu>
- Sender: Research in auditory perception <AUDITORY@xxxxxxxxxxxxx>
Having successfully used the up/down technique to get estimates of
psychometric functions for different % correct levels in various
psychoacoustic tasks (see Levitt, 1970, Journal of the Acoustical Sociery
of America, V49 #2, pp467), it was suggested I look into PEST (Parameter
Estimation by Sequentual Testing) as a more efficient adaptive procedure.
The original reference is Taylor & Creelman, 1967, JASA, V41 #4, pp782f.
My (current) application? I want to find difference limens at 75% correct
in psychiatric patient populations and so want to do the measurement with
the least number of trials possible.
While I think I understand the basic concepts of the 1967 PEST paper, I
do *not* understand how to determine the parameters of the algorithm for
a given "probability of positive response" (P sub t in the paper). I
also don't fully understand the meaning of W. The paper references a
book by Wald (1947, "Sequential Analysis") which I admit not to have seen
yet. Would this shed some illumination?
So, my questions: Can someone offer any of 1) a pointer to a more recent
paper describing PEST and its theoretic efficiencies (and/or
implementations), 2) code fragments illustrating an actual computer
implementation, or 3) an intuitive explanation of the variables and their
effects in the PEST procedure?
Many thanks in advance,
Peter "maybe I need RAID?" Marvit
: Peter Marvit <firstname.lastname@example.org> :
: Psychology Department, University of Pennsylvania :
: 3815 Walnut St., Philadelphia, PA 19104 w:215/898-9208 h:215/387-6433 :