for a complete beginner's intro to the fascinating world of neuroscience.
The following demo explores the effect of temporal regularity, or rhythmicity, on stream segregation. It uses the stimuli used in the study by Rajendran and colleagues (2013 JASA-EL).
This demo works well with recent versions of Google Chrome, Firefox and Safari, not yet tested with Internet Explorer. It does not work with most mobile browsers.
This podcast by science journalist Dr Carinne Piekema explores how hearing loss affects people, in particular how it affects musicians, and what modern prosthetic devices such as hearing aids or cochlear implants can and cannot do for these patients. It contains insightful interviews with inspirational deaf musicians, some of the UKs leading hearing researchers, as well as simulations designed to show to normal listeners what it would be like to have to rely on a hearing aid or a cochlear implant.
You can listen to the podcast here,
Humans show evidence of being able to preattentively extract rather complex rules governing a stimulation sequence. One of the most extreme examples in the literature comes from a paper by Paavilainen, Arajarvi, and Takegata (2007), as described in chapter 6 of the book.
Here is a sequence of sounds following the rule used in that paper. It is composed of four possible stimuli: a high frequency tone and a low frequency tone, each with either a short duration or a long duration. Can you find what is the rule that govern the sequence?
Here's an illustration of streaming by amplitude modulation. The sounds you will hear are all sinusoidally amplitude-modulated pure tones. The carrier frequency is always at 6 kHz. The galloping rhythm is produced by an 'A' tone that is modulated at a rate of 100 Hz while the modulation frequency of the 'B' tone can be changed from 106 Hz to 800 Hz.
This demonstration illustrates the inharmonic vowels used by de Cheveigné to study double vowel identification. The software used to synthesize these vowels is courtesy of Alain de Cheveigné.
One of the most intensively used paradigm for studying simultaneous sound segregation is the identification of double vowels. The most important result discussed in Chapter 6 of the book is the finding that the introduction of a difference in the pitch of the two vowels improves their identification.
Streaming has been used by classical composers as a way of creating simultaneous multiple melodies with an instrument that can produce only one note at a time. The standard examples come from Bach's compositions for violin solo.
This is yet another example of streaming, using the 'galloping', or 'ABA' rhythm paradigm. The two possible perceptual states of this sequence are illustrated in the figure below (this is Fig. 6-11 of the book). When the repetition rate is slow, or the interval between the two tones is small, the sequence is usually perceived as a 3-note melody with a galloping rhythm. At faster rates, or when the interval between the two tones is large, the sequence breaks down into two streams, the upper one at half the repetition rate of the lower one.