A theory of music cognition Day 4

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A theory of music cognitionDay 4

• Music Cognition
• MUSC 495.02, NSCI 466, NSCI 710.03
• Harry Howard
• Barbara Jazwinski
• Tulane University

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Course administration

• Spend provost's money

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A theory of music cognition
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What question should a theory of music cognition
answer?

• It's not a rhetorical question. Take a few
  minutes to discuss it with someone.
• Some answers I've found, with no pretence to
  authority
• What happens when I hear music?
• How do I hear music?
• What y'all have said
• how does the brain perceive and interact with
  music?
• what is music what is cognition?
• how does the brain differentiate between music,
  language, and noise
• course objectives
• how does the brain interpret the external stimuli
  of music and process it into something
  meaningful?
• how does the brain integrate all the parts of
  music?

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My answerdrawn from language cognition

• What will the next note be?
• Advantages
• It joins perception and production
• What is the next note that I will hear?
• What is the next note that I will play?
• It is easy to verify
• It is easy to quantify
• Disadvantages
• It ignores the emotional content of the next note
• What will the next note be, and will I like it?

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This is a question of predictionHere's an
example

• Sitting in my living room, I hear my wife call
  "mails here!" from the next room, and within a
  few seconds I am heading toward the front door to
  retrieve the days offerings from the mailbox.
• But what just happened?
• Take a few minutes to discuss what just happened
  with a friend.

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What just happened

• A pattern of sound energy impacted my ears, which
  I decoded as the words "mails here" spoken by my
  wife.
• I infer
• that there is mail waiting for me,
• that I am being given an oblique instruction to
  pick it up,
• and that there is indeed something worth picking
  up.

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But none of these inferential leaps is infallible

• It is possible
• that the words spoken were not "mails here", but
  "Mels here" an unexpected visit from our
  neighbor Mel
• or that, although something did indeed come
  through our mail slot, it was not the U.S. mail
  but a flyer from a local restaurant
• or that the mail has been delivered, but is
  nothing but junk (the most likely possibility)
• or that my wife simply said "mails here" as an
  informational update, and has already gone to
  pick up the mail herself.
• My pondering of the situation reflects all of
  these uncertainties, and the complex interactions
  between them.
• If I dont actually have a neighbor named Mel,
  for example, then the probability that my wife
  said "Mels here" is decreased.

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The next note

• But a moment later, these dilemmas are largely
  resolved.
• I hear a louder, clearer, more insistent "The
  mail is here!" from my wife,
• which clarifies
• both the words that were spoken
• and the intent behind them she does expect me
  to get the mail.
• (Whether the mail contains anything worth getting
  remains to be discovered.)

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The moral

• This everyday situation captures several
  important things about the probabilistic nature
  of thought and perception.
• Perception is a multi-leveled inferential process
• Probabilistic judgments are shaped by our past
  experience
• Producers of communication are sensitive to its
  probabilistic and fallible nature, and may adjust
  their behavior accordingly

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Perception is a multi-leveled inferential process

• Levels of knowledge in the story
• I hear sounds,
• infer words from them,
• infer my wifes intended message from the words
  (and from the way she said them),
• and make further inferences about the state of
  the world.
• Each of these levels of knowledge contains some
  uncertainty, which may endure in my mind
• even heading for the door, I may be uncertain as
  to what my wife said.
• As such, they lend themselves very naturally to a
  probabilistic treatment, where propositions are
  represented
• not in true-or-false terms
• but in levels of probability.

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Probabilistic judgments are shaped by our past
experience

• That is, by our observation of events in the
  world.
• In judging the likelihood
• that my wife wants me to get the mail,
• or that the mail (not Mel) is at the door,
• or that it contains something besides junk,
• I am influenced by the frequency of these various
  events happening in the past.

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Sensitivity to probability

• My wife knew that I had not fully gotten her
  message the first time,
• and thus re-conveyed both the words and the
  intention in an amplified form.

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Relevance for music cognition

• Let me rephrase the principles
• Perception of music is an uncertain multileveled
  inferential process.
• Knowledge of musical probabilities comes, in
  large part, from regularities in the musical
  environment.
• Producers of musical communication are sensitive
  to, and affected by, its probabilistic nature.

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Perception of music is an uncertain multileveled
inferential process

• In listening to a piece of music, we hear a
  pattern of notes and we draw conclusions about
  the underlying structures that gave rise to those
  notes
• These judgments are often somewhat uncertain and
  this uncertainty applies not just at the moment
  that the judgment is made, but to the way it is
  represented in memory.
• In the development section of a sonata movement,
  for example, we may be uncertain as to what key
  we are really in
• this ambiguity is an important part of musical
  experience.

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Perception of music is an uncertain multileveled
inferential process, 2

• The probabilistic nature of music perception
  applies not only to these underlying structures,
  but also to the note pattern itself.
• certain note patterns are probable, others are
  not
• our mental representation of these probabilities
  accounts for important musical phenomena
• surprise
• tension
• expectation
• error detection
• pitch identification

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Knowledge of musical probabilities comes from
regularities in the musical environment

• The probabilities we assign to note patterns and
  to the structures underlying them are shaped by
  our musical experience.
• Proof of this is seen in the fact that people
  with different musical backgrounds have different
  musical expectations, perceptions, and modes of
  processing and understanding music.
• This is not to say
• that our musical knowledge is entirely the result
  of environmental influence,
• or that it can be shaped without limit by that
  environment.

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Producers of musical communication are sensitive
to, and affected by, its probabilistic nature

• In many cases, music production is affected by
  perception, adjusting and evolving to facilitate
  the perceptual process.
• This is reflected
• in spontaneous individual choices
• for example, with regard to performance
  expression
• and in the long-term evolution of musical styles
  and conventions.

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Source

• The story about probability and its relevance for
  music is taken from pp. 2-3 of Temperley (2007)
  Music and Probability.
• The library has an e-book version of it, so you
  can view it online.
• Note that Temperley does not propose any
  particular theory of music cognition, except to
  imply that whatever it is, it is probabilistic.

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Hypothesis v. 2

• What is the next note probably going to be?
• And will I like it?

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Back to our regularly scheduled program
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Ingredients of music cognition mostly receptive,
mostly from Levitin
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Next Monday

• Perception, 1-2 of Levitin