Simultaneous Grouping Flashcards
Harmonic Relations
Moore, Glasberg & Peters (1985):
- periodic tones correspond to F0, whether F0 is present or not
- harmonic relations contribute to the computation of global pitch, even for small mistuning of up to 3%, more than which lead to the exclusion of the component from the complex tone
Hartmann, McAdams and Smith (1990):
- found that when mistunings reach about 1.5-2% they begin to be heard out
- after 3-4% it segregates from complex tone into separate stream with different pitch and timbre
Diuhfurs et al (1982) & Scheffers (1983) - Harmonic Sieve
- auditory systems applies an internal template for periodic tones, in which most components should pass and have the least empty slots
- components that fall outside these slots are excluded
Brunstrom & Roberts (1998)
- provided evidence for idea of harmonic sieve
- harmonic within a complex tone were removed
- participants listened to various probes and were to hit a button every time the probe was heard out from rest of the complex tone
- if the harmonic template is activated by the rest of the spectral frame, then the probe should be suppressed (unable to be heard out when aligned with missing harmonic components)
- hit rate minima aligned with positions of missing components of harmonic, indicating they were not heard out when it matched the rest of the complex
- this was also true when F0 on either side of missing components was changed, indicating the concurrent activation of two different templates
Roberts & Bregman (1991) - Spectral Relations
- investigated whether harmonic relations were the only factor influencing grouping by changing spectral shape
- investigated harmonics that were related but all even numbered harmonics were removed with the exception of one
- participants completed clarity rating task indicating whether the added even could be heard out
- found that even harmonics segregated from odds, indicating that spacing between spectral pattern also influences grouping
Roberts (2005)
- found that influence of spectral pattern was also true even if harmonics were not related but still evenly spaced
Onset Asynchrony in the Detection of Change
Darwin (1984): onset asynchrony of 30-40ms is sufficient to reduce the contribution of leading component to timbre of vowel quality
Dawrin & Ciocca (1992): onset asynchrony of 300-400ms required to reduce contribution of leading component to pitch
Peripheral Adaptation Mechanism
- initial réponse stronger than subsequent response
- response to leading asynchronous component has already been adapted therefore reducing its contribution to harmonic
Roberts & Moore (1991) - Onset and Offset Asynchrony
- investigated peripheral adaptation mechanism by comparing the effect of onset and offset asynchrony
- if PA is true then lagging component should not influence its contribution to harmonic, however they found that it did
- therefore cannot be explained by PA
Darwin & Sutherland (1984) - Captor effect in Asynchrony
- added a captor tone asynchronous leading component at double the frequency and found that this restored the contribution of the asynchronous component to the harmonic
- this is due to the grouping of the asynchronous component and the captor
- if PA were true then the captor and asynchronous component should have been adapted and therefore their contribution to the complex should have been reduced
Roberts & Holmes (2006) - found that this is due to the near-synchronous ending of the captor and start of the vowel
- if the end of the captor is not synchronous with the start of the vowel, this effect is no longer apparent.
Bregman et al (1991) - Abrupt changes
- abrupt changes in rise time trigger segregation
- old plus new heuristic
Common Fate
- correlated changes in frequency (coherent FM) cause segregation
- this segregation is dependant on the rate of modulation
Carlyon (1991) - the influence of coherent FM is only indirectly through harmonic relations
- it only leads to segregation because it introduces mistuning cues, which leads to grouping based on harmonic relations
Darwin (1992) - changes in coherent AM have no effect on segregation as changes in level do not lead to other grouping cues e.g. mistuning/harmonic relations
- highlights that coherent AM and FM do not have direct influences on grouping
Abrupt changes in spatial location
Kubovy et al (1974) - used changes in ITD’s to demonstrate grouping effects
- participants are played 8 tones and for each component at a time, a brief ITD was introduced
- a constant chord of the 8 pure tones was head in the centre of space, and ascending scale heard in the left ear
- this indicated grouping based on spatial location, however only because the changes in location were abrupt, therefore effect is indirect
Shackleton et al (1992)
- investigated ITD changes that weren’t abrupt
- if changes in F0 were introduced, then grouping was based on that
Darwin & Ciocca (1992) - investigated this effect using dichotic presentation (most extreme change in location)
- found that spatial location was not a strong grouping cue, rather grouping was based on near-synchronicity and harmonic relations between components
Turgeon et al (2005) - RMR
- an integration between sequential and simultaneous grouping
- participants are presented with a series of pure tones with small, regular gaps between them
- maskers are then introduced which are the same as the target but randomly spaced which makes the target sequence difficult to hear
- if maskers are paired with flankers that are harmonically related to them, they capture the maskers therefore segregating them from the target
- however, when the masker and captors are asynchronous, this effect is no longer present, therefore capturing effect is dependant on the synchrony of the masker with the flanker
