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Speech & Music

Speech & Music. PSY 295 – Sensation & Perception Christopher DiMattina , PhD. Music. Music has powerful emotional effects. Study by Blood and Zatorre (2001) Subjects listened to music which was emotionally compelling to them and gave them ‘chills’ PET imaging of brain activity .

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Speech & Music

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  1. Speech & Music PSY 295 – Sensation & Perception Christopher DiMattina, PhD

  2. Music PSY 295 - Grinnell College - Fall 2012

  3. Music has powerful emotional effects • Study by Blood and Zatorre (2001) • Subjects listened to music which was emotionally compelling to them and gave them ‘chills’ • PET imaging of brain activity PSY 295 - Grinnell College - Fall 2012

  4. Physiological effects • Changes in heart rate, breathing, muscle tone PSY 295 - Grinnell College - Fall 2012

  5. Brain effects • Increase in activity in brain areas related to reward (ventral striatum, left dorsal midbrain) • Decrease in other areas (amygdala) PSY 295 - Grinnell College - Fall 2012

  6. Other studies • Music can reduce pain • Promote positive emotions • Alleviate stress PSY 295 - Grinnell College - Fall 2012

  7. Musical notes • Pitch is the psychological quality of perceived frequency • As we recall from the missing fundamental demo, not necessarily the same as actual spectral energy PSY 295 - Grinnell College - Fall 2012

  8. Pitch neurons in A1 • Neurons in A1 show sensitivity to perceived musical pitch (Bendor & Wang 2005) PSY 295 - Grinnell College - Fall 2012

  9. Musical Scale • Musical notes go from 25 Hz to 4000 Hz • Different instruments cover different ranges PSY 295 - Grinnell College - Fall 2012

  10. Octave • If one tone has twice the frequency of another, they are 1 octave apart • Sound more similar than tones with nearby frequencies (pitch is not simply frequency!) • Middle C sounds more like High C than Middle D PSY 295 - Grinnell College - Fall 2012

  11. Helix • Can describe pitch by two dimensions • Tone height (frequency) and chroma (color) PSY 295 - Grinnell College - Fall 2012

  12. Pitch and temporal coding • Frequency can be encoded by both place and temporal coding • Temporal coding weak above 5000 Hz • Pitch is weak above 5000 Hz – sequence of tones does not convey melody well PSY 295 - Grinnell College - Fall 2012

  13. Chords • A chord is a set of three notes of different pitch which are played together • Mathematical ratios of frequency determine chord quality • Consonant chords have simple ratios (2:1, 3:4, ) • Dissonant chords have complex ratios (16:15, 45:32) PSY 295 - Grinnell College - Fall 2012

  14. Web activity • http://sites.sinauer.com/wolfe3e/chap11/notesF.htm PSY 295 - Grinnell College - Fall 2012

  15. Speech PSY 295 - Grinnell College - Fall 2012

  16. Basic anatomy • Larynx – houses the vibrating vocal chords • Vocal tract – airway above the larynx used for production of speech PSY 295 - Grinnell College - Fall 2012

  17. Respiration and phonation • Phonation – process where air is pushed out of lungs and vocal chords vibrate (vary tension of vocal folds) • Articulation – changing shape of vocal tract to produce speech sounds PSY 295 - Grinnell College - Fall 2012

  18. Harmonic spectrum • Vibrations of the vocal folds create a harmonic spectrum • Spectrum needs to be shaped by vocal tract to give recognizable speech PSY 295 - Grinnell College - Fall 2012

  19. Articulation • Changing size and shape of vocal pathway changes the filter function applied to the harmonic spectrum PSY 295 - Grinnell College - Fall 2012

  20. Formants • Peaks in the speech spectrum are called formants • Different vowels are specified by their formants PSY 295 - Grinnell College - Fall 2012

  21. Spectrograms • Vowels are steady-state and characterized by their spectra • Most other sounds (consonants) vary over time and must be characterized by their spectrogram PSY 295 - Grinnell College - Fall 2012

  22. Vowel sounds of english • Vowels differ by location of tongue (low/high, front/back) PSY 295 - Grinnell College - Fall 2012

  23. Voiced and voiceless consontants • Voiced – vocal chords vibrating • Voiceless – vocal chords not vibrating PSY 295 - Grinnell College - Fall 2012

  24. Coarticulation • Acoustic properties of speech sounds depend on previous and subsequent speech sounds – coarticulation • In book, say ‘moody’ and ‘eedoom’ – path of tounge different and ‘d’ sounds different • Context sensitivity means there are no invariants of speech sounds – hard for computer speech recognition PSY 295 - Grinnell College - Fall 2012

  25. Coarticulation • The formant transition for F1 is the same for ‘bah’,’dah’,’gah’ when they preceed the same vowel • They differ when proceeding different vowels PSY 295 - Grinnell College - Fall 2012

  26. Categorical perception • For most stimuli, gradually changing parameters gradually changes perception • For speech this does not hold • Cannot discriminate sounds with the same category label • Perception ‘jumps’ for equidistant sounds with different category labels PSY 295 - Grinnell College - Fall 2012

  27. Categorical perception PSY 295 - Grinnell College - Fall 2012

  28. Primate vocalization morphing • Can study categorical perception in other species (DiMattina & Wang 2006) PSY 295 - Grinnell College - Fall 2012

  29. Is speech special? • “Motor theory” – processes used to produce speech sounds are used to understand speech • Problem with this: Other species which don’t produce human speech can learn to categorically perceive human speech PSY 295 - Grinnell College - Fall 2012

  30. Categorical perception is ubiquitous • Many complex stimuli are perceived categorically PSY 295 - Grinnell College - Fall 2012

  31. Web activity • http://sites.sinauer.com/wolfe3e/chap11/catpercepF.htm PSY 295 - Grinnell College - Fall 2012

  32. McGurk Effect • http://sites.sinauer.com/wolfe3e/chap11/mcgurkF.htm PSY 295 - Grinnell College - Fall 2012

  33. McGurk Effect • Visual articulation cues bias auditory perception PSY 295 - Grinnell College - Fall 2012

  34. BBC • http://www.youtube.com/watch?v=G-lN8vWm3m0 PSY 295 - Grinnell College - Fall 2012

  35. Speech and the brain PSY 295 - Grinnell College - Fall 2012

  36. Cochlear implants PSY 295 - Grinnell College - Fall 2012

  37. Speech with cochlear implants • http://sens.com/helps/demo05/helps_d05a_RK_7055_CI_20_65a.htm PSY 295 - Grinnell College - Fall 2012

  38. Speech perception in A1 • Complex sounds, including speech, activate area A1 • However, speech sounds activate areas more anterior and ventral to A1 PSY 295 - Grinnell College - Fall 2012

  39. Electrode arrays • Neural activity in auditory regions shows categorical perception of syllables ‘bah’, ‘dah’, ‘gah’ PSY 295 - Grinnell College - Fall 2012

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