Re: [AUDITORY] Estimation of auditory sensory thresholds from below: any evidence?

[Ken Grant <ken.w.grant@xxxxxxxxx>]

I agree that starting the track with easy trials have proved to be beneficial. However, this is when each trial presents a different token, and the cues used by listeners change throughout the track.  

Coming from below and repeating the same token over and over  treats every speech (sentence) as it’s own separate track, and very few sentences are needed. This may be necessary if the study compares several different conditions. 

The initial trial is typically below the targeted performance level and subjects have no trouble quickly moving on from a very poor SNR to something better. To speed things up further, after the first sentence is presented we start the next sentence at the previous SNR threshold minus 5 dB (may have to be closer to 10 dB if the next sentence presented is too easy and the targeted performance level exceeded). This ensures that the first time a sentence is played, recognition performance is below the targeted performance level. 

Ken W. Grant, Ph.D.
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On Tue, Nov 21, 2023 at 12:13 AM Les Bernstein <lbernstein@xxxxxxxx> wrote:

Of course, there is no auditory "threshold" and Dr. Dennis McFadden has argued for years that the use of the term to indicate the magnitude of the independent variable corresponding to a given level of performance is to confuse the historical background.  Although he is quite correct, I have no illusions that people will retire the term.  As for starting from "above," I agree with Dick.  It's a more efficient way to conduct an experiment.  Still, in an objective psychophysical task with feedback, one could start from below.   Taking the 2-down, 1-up Levitt tracker as an example, in practice, starting from below tends to result in a bunch of "wasted" trials.  The method of limits is, of course, a biased psychophysical procedure that has its own set of issues.

Les

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On 11/18/2023 12:30 AM, Richard F. Lyon wrote:

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I think the subject needs to feel like they're doing the job well, so starting easy (above threshold) makes sense.  And they get to know very well what signal to listen for.

If you approach from below, they don't know what signal to expect, so may not be in an "optimal detector" state of mind.

Dick

On Fri, Nov 17, 2023 at 9:19 PM Massimo Grassi <massimo.grassi@xxxxxxxx> wrote:

Dear all,

I was recently writing a paper about threshold estimation in hearing and at some point I stopped. 

Let suppose you are estimating a frequency discrimination threshold with a classic 2-down 1-up staircase rule (Levitt, 1971). Theoretically, you could approach the threshold from below or from above, I repeat this every year to 1st year students when I teach them the method of limits! In practice, however, in psychoacoustics we rarely-to-never approach the threshold from below.

Is there any reason for this "tradition"? I know the psychometric function should be symmetric below and above threshold! But this does not explain the "tradition"!

All the best from "it is almost winter" North East Italy.

m