Subject: Re: [AUDITORY] Matlab Code for interleaved adaptive procedure From: Owen Brimijoin <owen@xxxxxxxx> Date: Wed, 26 Jun 2013 16:00:27 +0100 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dear Emmanuel and the List, I have something that might help. A while back I realized I was wasting a little time with each new experiment I built, scratching my noodle over the rules governing what to do with a signal in an adaptive track. I wanted a simple function that was flexible enough to cover all the usages I could think of, because let's face it, each time we want to measure some threshold we always need something to be a little bit different, right? That said, there's one thing that's always the same, namely the need to know what to do with the signal on the next trial. Do I increment the level? Decrement it? If so by how much? Do I leave it the same? When is the track 'done?' To solve these pesky recurring problems, I wrote a compact function called adaptive_track_engine.m and posted it on the Mathworks file exchange: http://www.mathworks.co.uk/matlabcentral/fileexchange/40892-adaptive-track-engine You give it the history of the listener's answers up to that point, the step sizes and number of reversals you want in each stage, and any arbitrary adaptive rules (like 3 down 1 up or, equally, something bizarre like .. say... 2 down 6 up). It returns what you need to do to the signal on the next trial and tells you when the track is finished. Simple as that. I've added an example for how to use adaptive_track_engine to do multiple interleaved tracks in the zip file on that page. It's important to note that this is NOT a ready-to-play psychometric threshold estimation program. If that's all you want, there are any number of commercial or free standalone complete programs available elsewhere. The idea behind this function was to be as flexible as possible so that it could be used in *any* custom adaptive track program. The core function also allows scalar output, making it flexible enough to use in, for example, an adaptive minimum audible angle measurement too (to change degrees instead of dB). Not incidentally, I'd be awfully grateful if any of the readers of the Auditory List had suggestions for how to improve its flexibility. Best of luck and I hope this helps! -Owen. -- --------------------------------- W. Owen Brimijoin MRC Institute of Hearing Research Glasgow, United Kingdom owen@xxxxxxxx ---------------------------------