The Musical Mind:

Insights from Congenital Amusia

Dr. Vicky Williamson

http://www.gold.ac.uk/music-mind-brain/

http://www.gold.ac.uk/psychology/staff/victoria-williamson/

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Overview

• What is amusia? How is it diagnosed?

• Behavioural studies – what is difficult?

• How music overlaps with other cognitive processes

• Neurological studies; structural and functional

• How their abilities and brain structure inform about typical music processing

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We are born ‘musical’• Preference for consonance at

2 days (Deaf parents: Masataka, 2006).

• Notice changes to contour (ups and downs) but not intervals (Trehub et al,1997)

• Respond to phrase structure in Mozart (Krumhansl & Jusczyk, 1990)

• Can distinguish different rhythm deviations at 2 days (Winkler et al. 2008)

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Natural musical development

• Newborn – perceive and remember pitch sequences, sensitivity to contour, preference for consonance

• 4-6yrs – Respond to tonal more than atonal music

• 7yrs – Sensitive to the rules of implied harmony

• 10yrs – Understand finer aspects of key structure

• 12yrs – Begin to develop tastes and recognition of definite styles

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What is amusia?

• People are born with the ability to internalize the music of their own culture (Hannon & Trehub, 2005)

• Amusia: Lifelong difficulties with music perception (production)

• Not acquired

• Estimated ~4% of the population (Kalmus & Fry, 1980)

• No hearing loss, lack of exposure to music, social or cognitive impairments (Peretz et al., 2002; Ayotte et al., 2002)

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If you were amusic…• You report having the condition for as long as you can

remember

• Typically unaware when music, including your own singing, is off-key

• Only ~50% have difficulties with rhythm

• Difficulty discriminating or recognizing melodies without lyrics

• May dislike musical sounds and even avoid public places and situations where music occurs.

• Significantly less likely to “use” music in everyday life or experience reactions such as chills, relaxation or mood enhancement

(Ayotte et al, 2002; Peretz et al, 2003; McDonald & Stewart, 2008Ayotte et al, 2002; Peretz et al, 2003; McDonald & Stewart, 2008)

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AMUSICS

CONTROLS

Agree Unsure Disagree Agree Unsure Disagree

Memories 86% 10% 5% 100% 0% 0%

Shivers 43% 14% 43% 91% 0% 10%

Match mood 57% 14% 29% 100% 0% 0%

Catharsis 38% 14% 48% 100% 0% 0%

Relax 52% 0% 48% 100% 0% 0%

Uplift 33% 5% 62% 100% 0% 0%

Sadden 48% 10% 43% 95% 0% 5%

Comfort 29% 10% 62% 95% 0% 5%

Motivate 48% 10% 43% 100% 0% 0%

Spiritual 24% 24% 52% 72% 10% 19%

Psychological Functions

McDonald & Stewart, Music Perception (2008)

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Some (possible) examples

• Milton Friedman – Nobel prize winning economist

• President Theodore Roosevelt

• Che Guevara

• Florence Foster Jenkins

• King Alfonso XIII of Spain - (Anthem servant)

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Why is amusia interesting?

• Sheds light on cognitive, neural and potentially genetic basis of normal musical processing

• Can address questions concerning the extent to which musical capacities are associated with other capacities (language, spatial awareness)

• May shed light on possible origins of other developmental (congenital) disorders such as dyslexia, prosopagnosia and dyscalculia

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Diagnosis - MBEAThe Montreal Battery for the Evaluation of Amusia

Hear 2 melodies and say same or different

Subtests: Scale, Contour, Interval, Rhythm, Meter (Memory)

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1) Pitch Perception Deficits

• What is the smallest difference in pitch that can be detected? (Pitch Change)

• What is the smallest difference in pitch that can be discriminated? *

(Pitch Direction)

What type of test to use?

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Stimulus

Pitch Identification

‘Report up or down’

Pitch Production

‘Imitate the pitch change’

Gliding tone

Segmented tones

Based on Loui et al. (2008)

Testing pitch direction

0

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Problem: Really excessive thresholds!

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An alternative – AXB tasks

Pitch Detection

Pitch Direction

The advantage of this task is that it is ''criterion free'' (Macmillan & Creelman, 2005)

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AXB thresholds

Williamson et al. 2012Neuropsychologia

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Conclusions: Pitch Perception

• Many amusics can detect pitch changes but have problems discriminating direction

• Right Heschl’s gyrus lesions (Johnsrude et al. 2000),

bilateral lesions of AC (Tramo et al. 2002), and ‘direction poor’ listeners (Mathias, Micheyl & Bailey, 2010)

• Affects the small changes which are often used in (western) music (e.g. semitones)

• Amusic thresholds are sensitive to task demands

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2) Pitch memory problemsWilliamson & Stewart (2010) – Memory

N = 28 (14 amusics)

• Tone span (how many tones can you remember?)

• Digit span (similar test)

• Both tasks use a list probe recognition paradigm, and a 2up 1down adaptive tracking staircase procedure.

• Working memory span (Operation span – Professor Randall Engle)

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Amusic’s tracks

Digits Tones

Span = Average of last 6 reversalsSpan = Average of last 6 reversals

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Findings

• Amusics have lower spans for tones but not digits

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Conclusions: Memory

• Significantly reduced tone span but comparable digit span

No general short-term memory problem

• Influence of pitch perception (direction) problems only arguable in two extreme cases.

• Supporting evidence: Inability to maintain pitch sounds in memory (Williamson et al. 2010, Advances in Cognitive Psychology)

• Around 20% may have reduced working memory = poorer attention?

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3) Speech problems?

• Pitch is important to audible speech• Especially if we are apart.

1) Tone languages (65%)2) Intonation: Question to statement, convey

attitude.3) Speaker Identity

• Do amusics have trouble hearing speech?

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Liu et al.(2010) Brain

Statement-question discrimination with SUBTLE pitch changes:

1. Natural speech 2. Gliding tones 3. Nonsense speech

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Natural speech Gliding tones Nonsense speech

* * *

amusic control

Most amusics have difficulties with all 3 tasks

amusic control amusic control

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Conclusions: Speech

• Difficulty with subtle speech prosody

• No difficulty with ‘natural’ sentence stimuli (Patel et al. 2008)

• Not a huge problem in real life:

1)Large pitch leaps (5-12 semitones)2)Semantic and sentence context

• But important processing overlap

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4) A spatial problem?

• Pitch has a spatial association

•“Lower” or “Higher”• The musical stave

•SMARC effect (Rusconi et al., 2006)

•Musicians better on spatial tasks (Brochard et al., 2004)

•Amusia as a failure to implement a spatial representation of pitch?

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Supportive evidence

NB. No overall difference in reaction times

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Visuo-spatial tasks Williamson, Cocchini & Stewart (2011) – Brain and Cognition

• MBEA

• Pitch detection and direction discrimination thresholds

• Mental Rotation – Shepard & Metzler

figures

• Visual Patterns Test (VPT)

– visual memory

• Corsi Blocks – spatial sequence

memory

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Results

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Conclusions: Wider cognition

• Amusia is associated with wider pattern of difficulties than just pitch perception...but...

• All difficulties have a pitch basis

• Spatial difficulties in amusia have not been replicated in two published studies

• Unique view of processes that underlie music cognition

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Neurological underpinnings

• No difference in structure of PAC

• Hyde et al. (2006) measured white matter density between the right frontal and temporal lobes.

• Amusics white matter was thinner, suggests a weaker connection.

• Severity of Amusia = Thinner white matter.

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Diffusion tensor tractography studies

• Loui et al. (2009) – Arcuate fasciculus (AF).

• “Disconnection” in the temporal-frontal pathway

• Abnormal migration of proteins along tract

• Underdev of higher order musical processing

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In 9/10 Amusics the right superior AF (red) was unidentifiable

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EEG study of melodic expectancy (Omigie, Pearce, Williamson & Stewart, in revision)

• Task: Detection of expected or unexpected notes in a melody (Pearce and Wiggins, 2006; Pearce et al. 2010) using an implicit (timbre) and explicit task

• Previous finding: Amusics were comparable in the implicit task but significantly worse at explicit recognition of unexpected notes

• Present study: EEG while listening to real melodies . ERPs associated with the recognition of an unexpected musical event (ERAN/N1; 150ms)

• Hypothesis: Amusics will show attenuated responses

• N = 30 (15 amusics): 58 hymns in electronic piano (32 or 64 notes long), all but first 2-4 notes divided into 3 ‘bins’ of low, medium and high expectancy

• Listen to the melodies and detect any deviation in timbre

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Results• Less expected notes =

ERAN/N1 in controls that was diminished in amusics

• Amusics have internalised the regularities of music but have less robust representation

• Supported by studies of musicians (Koelsch et al. 1999; 2007)

• Early pre-attentive mechanisms increase probability that change will be consciously perceived (Teemu Rinne et al. 2006)

Scalp maps showing voltage and illustrating the negativity in the N1 time window for low, medium and high expected notes, and the difference in voltage between the low and high IC conditions.

Amusics

Controls

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Conclusions• Congenital Amusia is a neurodevelopment disorder that impacts on

music listening (and production)

• Pitch perception problems; discriminating pitch direction

• Pitch memory weaknesses

• Carry over into subtle speech difficulties

• But no spatial difficulties

• Most likely brain origin is a breakdown in pathways that carry pitch-based information to higher centres (role in other ND disorders)

• Diminished explicit awareness of change alongside intact implicit knowledge – links back to task sensitivity issues in pitch perception

• Insight into the organisation of musical mind.

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Thanks for listening

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