Subject: Re: Stimulus properties of sound streams From: Al Bregman <BREGMAN(at)HEBB.PSYCH.MCGILL.CA> Date: Sun, 25 Mar 2001 23:07:19 -0500Dear Jan, I have inserted my replies between your questions. They aren't based on specific pieces of research but on my own expectations (and sheer guesses) after listening to many types of laboratory sounds. > 1.. what properties of the sound streams make it easy or difficult for the > listener to pre-attentively perceive a change in the display, An abrupt increase in loudness should facilitate the registration of the change; however, it might also attract attention to itself, so that it didn't remain pre-attentive. Of course, the greater the magnitude of the change, the easier it would be to pre-attentively register the change. Also changes in louder streams should be most easily registered. Finally, the greater the magnitude of the difference that segregates one stream from the others, the easier it should be to register a difference in that stream. > 2.. what properties facilitate the voluntary direction of attention to the > changing auditory dimensions within a stream, for eg. pitch and/or tempo, so > that information about the variable of interest can be extracted. If there are several streams, each with a different pitch range or frequency range, changes in the highest should be more noticeable, followed by changes in the lowest, then by changes in the steams in the intermediate range (such as the inner voices in music (you may want to ask Caroline Palmer about this question: cpalmer(at)magnus.acs.ohio-state.edu). > I am wondering whether anyone has some thoughts about whether auditory > stimulus dimensions can be integral or separable, along the lines of > Garner's (1970, 1974)classification of visual stimuli. Integral dimensions > facilitate tasks where both dimensions are attended to, but interfere with > tasks where one dimension is attended to. Separable dimensions have the > opposite effect. While there are some reports in the literature of integral > auditory dimensions such as pitch and loudness, I haven't seen any reference > to separable dimensions, and in fact I'm wondering whether this is a concept > that could be applied to sound stimuli. I would imagine that the length of a sound (where the length is at least 400ms, to exceed the temporal integration window for loudness) would be separable from any steady-state property of the sound, such as pitch, loudness, or timbre. > The other concept I'm wondering > about is auditory emergent features. Visual emergent features have a strong > facilitative effect on monitoring performance - what would an auditory > emergent feature within a sound stream be like? A phoneme would be an emergent feature arising from the pattern of intensities of frequency components, whether or not the components are harmonic, inharmonic, or random (as in whisper). An example of an emergent feature in music is whether the chord is major or minor, or, indeed, any chord quality. A stream is also an emergent entity ("entity" rather than "feature"). Corresponding with visual shapes, which are emergent, are melodies. Timbral "brightness" can also be considered to be an emergent feature, arising from the relations among partials, with no partial essential in producing the brighness. Al ------------------------------------------------- Albert S. Bregman, Emeritus Professor Dept of Psychology, McGill University 1205 Docteur Penfield Avenue Montreal, QC, Canada H3A 1B1 Office: Phone: +1 (514) 398-6103 Fax: +1 (514) 398-4896 Home: Phone & Fax: +1 (514) 484-2592 Email: bregman(at)hebb.psych.mcgill.ca -------------------------------------------------