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PSYC 182 Auditory Illusions:Circularity and Speech

‘talking about music is likedancing about architecture’

Topics

• Pitch Circularity• Tritone Paradox• Sometimes Behave So

Strangely• Whistled Languages and Talking

Drums• “Ringing my Phone”

Grouping Mechanisms

• GestaltConcepts– Proximity– Similarity– Good

continuation– Common fate– Familiarity

Pitch – Perceptual Phenomena

Octave equivalence – a note doubled in frequencysounds similar to the original

• cross-cultural (cross-species?)

• 2 dimensions of pitch:– “pitch class” (circular) +

– “height” (linear)

Limits of octave equivalence:

• Mysterious Melody

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Helix

A’’

A’

A’’’

A

PC Circle

Pitch Circularity: Shepard Tones• Shepard (1964) decoupled these dimensions

– Minimized tone-height cues• 10 octave-spaced sine wave partials; spectral envelope

– Subjects judged tone pairs’ pitch: ‘’ or ‘’– Determined by pitch class proximity

Scale heard as endlessly ascending!

Escher

steps

gliss

Rissetrhythm

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Proximity: Shepard tones

• Octave-relatedcomplexes

• Follow by proximity– pitch class circle– smaller intervals

Pitch Circularity: A New Model• Attenuate odd harmonics

relative to even• Increase odd harmonics

with each step up• Overall pitch height drops

as scale ascends• Uses full harmonic series:

more natural sound

2 channel model

From Deutsch, D. Psychological Review, 1969

Relative amp odd-even

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Spec A

A

Spec As

A#

Spec B

B

Spec C

C

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Spec Cs

C#

Spec D

D

Spec Ds

D#

Spec E

E

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Spec F

F

Spec Fs

F#

Spec G

G

Spec Gs

G#

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Spec A

A

PrxInt 9 12

MDS All 9 MDS AB 12

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MDS B 12

PrxInt 9

Hi-lo 9

New Pitch Circularity

• New Circular Scale Steps

• New Circular Scale: Gliss

• New Circular Scale: Reverse Gliss

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Pitch Circularity in MusicCompositional technique (Braus, 1995)

– Evident in Western art music by 1500’s– Baroque, Romantic, & 20th Century– Modern composers used Shepard tones (Beck)

∞Reflects infinity-seeking compositionalaesthetic; climactic; builds tension

Tritone Paradox• Judging Shepard

tone-pairs:

• What happens w/oproximity cues(tritone)?

• Consistent perceptswithin subjects

Tritone: examples• Systematic variation

between subjects

– Geographic region(dialects)

– Pitch range of speech

– Mother-child similarities

Tritone Paradox: Data Sheet• For each tone pair:

⇑ if the 2nd pitch soundshigher than the 1st

⇓ if the 2nd pitch soundslower than the 1st

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Tritone Paradox: Key 1• 1st pitch of each

tone pair

• For each ⇓record the notename

• Count # of eachpitch class

Tritone Paradox: Key 2

• 1st pitch of eachtone pair

• For each ⇓record the notename

• Count # of eachpitch class

Tritone Paradox: Key 3

• 1st pitch of eachtone pair

• For each ⇓ recordnote name

• Count # of eachpitch class

Sometimes Behave So Strangely• Strangely 1: Strangely 2:

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Sometimes Behave So Strangely• A repeated phrase of normal speech• Begins to sound like song• The musical reinterpretation persists indefinitely

Parellels in Music & Language

• Common brain areas forprocessing musical andlinguistic syntax

• Music can facilitate theprocessing of words

• Emotion is conveyed bythe same acoustic cuesin both language & music

• Neuroimaging research supports syntactic overlap– musical syntactic processing activates 'language areas'

• Maess w/ MEG: early right anterior negativity ERAN– associated with harmonic processing in music– in left frontal language area (Broca's) & its RH homologue

• fMRI studies of harmonic processing:– activation of these areas and Wernicke's language area

Imaging and SyntaxWhistling a Language

• Whistles ≈ sine waves• (no timbral variation, consonants)• Pitch glides: vary range, contour, length• Silbo Gomero: Canary Island sheperds• 2 vowels, 4 consonants• Populations: typically isolated, sparse• Terrain: difficult, mountainous• Long distances (1-5 km)

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Silbo Gomero sound clips

• “Domingo is sick”• Domingo está enfermo

• “John milks the goats”• Juan ordéñame las cabras

Silbo Imaging: Methods

• Functional neuroimaging was acquiredwhile Silbadores and non-whistlers:

• listened passively to Silbo and Spanishsentences vs. a reversed-Silbo baseline

• monitored cycles of Silbo and Spanishwords for target words vs. a silent baseline

Silbo Imaging: Results

• Processing Silbo activated left hemisphere regionsassociated w/ spoken-language only in Silbadores

• No common cortical language areas found for Silboand speech in non-whistlers

• Language-processing regions adapt to a widerange of signaling forms

Talking Drum• Long distance

communication• Imitates language• West African tone

languages, e.g.Yoruba, Bantu

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Phone Conversation Melody

• Emphasizing melodic aspects of speech– Pitch, pitch contour– More apparent without focus on semantics

• “Ringing my Phone: Straight out ofIstanbul” by Jason Moran

Speech, Melody, and Palin• http://ca.youtube.com/watch?v=

9nlwwFZdXck