2. Pitch of unresolved harmonics: Evidence against autocorrelation Christian Kaernbach and Carsten Bogler Institut für Allgemeine Psychologie, Universität Leipzig Talk presented at “Pitch: Neural Coding and Perception” 4th-18th August, 2002, Hanse-Wissenschaftskolleg, Delmenhorst, Germany IntroductionPitch of unresolved harmonics The ur-modelLicklider, 1951 The argumentKaernbach & Demany, 1998 ConfirmationKaernbach & Bering, 2001 Trying to convincePilot data FailureShort survey on current models G rumble

3. Interlude Fugue G-major by Johann Mattheson from “ Wohlklingende Fingersprache ” performed by Gisela Gumz, Clavichord

4. single note of a clavichord, 518 Hz Pitch of unresolved harmonics SpectrogramExcitation pattern in the cochlea (LUT Ear)

5. simplification: slightly more complex: Processing of temporal structure  see Poster by Carsten Bogler

6. Studying temporal processing with clicks simple periodic: complex periodic: aperiodic:

7. Autocorrelation: The ur-model Licklider, 1951 from cochlea delay line fast line coincidence cells Autocorrelation in general s(t)  s(t-  )  w(t-t 0 ) dt   (s(t))  s(t-  ): triggered correlation (AIM) s(t) =the stimulus cochlea excitation simulated spike trains + coincidence recorded spike trains + coincidence  AC( ,t 0 ) =

8. abx 1st- versus 2nd-order temporal regularity Kaernbach and Demany, 1998 kxx : k = 5ms, x  [0,10] ms kkk abx : a  [0,10] ms, b = 10 - a, x  [0,10] ms a b kxxxkxxxx high-pass filtered, low-pass masked, Fc = 6 kHz x kxx

9. 1st- versus 2nd-order temporal regularity Kaernbach and Demany, 1998 target type:kxxkxxxkxxxxabx x  [0,10][0,10][0,10][0,10]ms AC peak at55510ms task: discriminate regular sequence from random sequence procedure: adaptive reduction of the length of the sequence abx [0,5] 5

10. abx 1st- versus 2nd-order temporal regularity Kaernbach and Demany, 1998 kxx : k = 5ms, x  [0,10] ms kkk abx : a  [0,10] ms, b = 10 - a, x  [0,10] ms a b kxxxkxxxx high-pass filtered, low-pass masked, Fc = 6 kHz x kxx  = 

11. Reducing the cut frequency Kaernbach and Bering, 2001 pitch JNDs for periodic click sequences, high-pass filtered, low-pass masked, for 15 subjects confirm Kaernbach & Demany with cut frequency = 2 kHz (x  [0,15] ms)

12. Simplifying abx & kxx too complicated. ab = periodic sequence + interfering clicks –Kaernbach & Demany 1998: vary amplitude of interfering clicks –vary cut frequency, compare with jnd (cf. Kaernbach & Bering, 2001) ab with a  [0,4], b = 8 - a, versus xy with x  [0,4], y  [4,8].

13. abx Summary of evidence kxxxkxxxx x kxx =  Further evidence: Carlyon, 1996 mixture of two complex tones composed of unresolved harmonics with different F 0 produces no clear-cut pitch percept Plack & White, 2000 pitch shifts due to variations of a gap between two click sequences are incompatible with autocorrelation ab xy

14. Survey on current models JASA online search autocorrelation (abstract type) psychological acoustics revised after 9/1998 applying/advocating autocorrelation Appeal AC modelers: test your models with 2nd-order regularities publish results (positive or negative) eventually: modify your models Appeal AC modelers: test your models with 2nd-order regularities publish results (positive or negative) eventually: modify your models

15. The Pisa effect