Subject: Re: phoneme recognition and stimulus length From: Richard Pastore <pastore(at)BINGHAMTON.EDU> Date: Mon, 19 Mar 2001 12:38:27 -0500Laszlo In papers of the 1970s, Dom Massaro (in several papers) and Dave Sparks both showed interference (drop in percent correct) in pitch identification of tones just above a threshold difference apart by a delayed following tone of intermediate frequency. Performance improved to an asymptotic level (but not to unmasked level) a with an ISI of 250 to 250 ms. Others [Barry Leshowitz & Ed Cudahy, (several papers in 1970s), and a paper by Chuck Watson & Bill Wroton (1980s)] measured delta-F threshold as a function of masker delay. At most, best, threshold performance was elevated out to approximately 110 ms. I am not sure that backward recognition masking is necessarily all that relevant to what is being discussed. Target tone duration is relevant to backward recognition masking. Don Ronken (early 70s) found a type of backward recognition masking when examining the frequency DL for brief tones - a trailing tone interfered with performance, but a preceding tone, if anything, improved performance. Finally, remember that the spectral bandwidth of stimulus is an inverse function of duration, and the perception of brief segments of tones are heard as clicks, tone pips, and finally as tones when duration is increased. If dealing with brief stimuli, Roy Patterson's work on minimum duration for different types of recognition is also definitely relevant. However, the questions being discussed seem to be about syllable-length stimuli, and thus time parameters that are longer than those in the literature I have tried to summarize. Dick Pastore At 05:39 PM 3/19/01 +0100, you wrote: >On Mon, 19 Mar 2001, Jont Allen wrote: > > > I dont know if this is what you are getting at, but have you looked at the > > paper by Sadaoki Furui "On the role of spectral transitions for speech > perception." > > JASA, Oct. 1986, page 1016+ > > >It partly answers my questions, as they used truncated syllables as >stimuli. But I would be more interested in the other direction: >is there any additional gain in recognition performace if we use stimuli >LONGER than a syllable? >What made me wonder about this is the "backwards recognition masking" >experiments of Massaro (unfortunately, I don't have the original papers, >only a half-page review in a Ph.D. thesis by Brian Kingsbury). Their >results say that masking has no effect if the target is longer than a >syllable or if there is at least a syllable-long silent interval between >the target and the masker. I would >need a reinforcement of these results, but possibly from the opposite >direction (i.e. not how recognition deteriorates from backwards masking >but how recognition improves from "forward helping" - so to say). > > Laszlo Toth > Hungarian Academy of Sciences * > Research Group on Artificial Intelligence * "Failure only begins > e-mail: tothl(at)inf.u-szeged.hu * when you stop trying" > http://www.inf.u-szeged.hu/~tothl * -------------------------------------------------------------------------------- Richard E. Pastore Professor of Psychology and Linguistics Binghamton University (SUNY University Center) Binghamton, NY 13902-6000 http://psychology.binghamton.edu/faculty/pastore.htm