1. Cold Spring Harbor Laboratory Cold Spring Harbor, NY USA
Development of a visuospatial representation method and evidence for rhythmic categorical perception
Amandine Penel, Christopher A. Hollweg, & Carlos D. Brody
Cold Spring Harbor Laboratory
Cold Spring Harbor, NY USA

2. Development of a visuospatial representation method to investigate the perception of temporal patterns
Serendipitous evidence for rhythmic categorical perception

3. How do they interact? Are they the only ones to operate? (unlikely)
Various processes have been proposed for the representation of temporal information in sequences, e.g.:
a multiple-look estimation of the mean time interval & variability (Drake & Botte, 1993)
the induction of a regular clock / entrainment of an attentional pulse (Povel & Essens, 1985; Large & Jones, 1999; Penel & Jones, 2005)
grouping by temporal proximity (Handel, 1998; Penel & Drake, 2004)
How do they interact? Are they the only ones to operate? (unlikely)

4. Mental representation?
Mental representation
Top-down rationale employed by research: hypothesis about a process, temporal patterns selected accordingly.
A complementary bottom-up approach (Exp.1): the visuospatial representation method is exhaustive, the theory can then be driven by the data.
Stimulus:
Auditory, temporal
Response:
Visual, spatial
1 sec
Fast, and if validated (Exp.1 control + Exp.2), gives a direct access to the mental representation.

5. Experiment 1 Method 1. Auditory experimental conditions
(2. Visual control condition)
1 or 1.2 sec sequences (blocked) of 3 short tones (4 msec), with the middle tone randomly dividing the interval (uniform distribution, 1 msec sampling).
1200 trials in each tempo condition in 8 1-hour sessions.

6. 2. Visual control condition
Experiment 1
(1. Auditory experimental conditions)
2. Visual control condition 1 2 3
steps
NO GO NO NO
1000 trials in 2 1-hour sessions.
8 Ps (nonmusicians and amateur musicians), half began/finished with the control, tempo further counterbalanced.

7. Results Raw data: For each participant:
Experiment 1
Results
Raw data:
For each participant:
1200 {stimulus, response} pairs in each auditory tempo condition, 1000 in the visual control condition.
Looks like Gert’s plot, doesn’t it?

8. Experiment 1
P2 1-sec tempo
Response (msec)
Stimulus (msec)

9. Average (N=8, 2 tempi + {N=4, 1 tempo Pilot}):
Experiment 1
Average (N=8, 2 tempi + {N=4, 1 tempo Pilot}):
Response (idem)
Stimulus (% deviation from midpoint)

10. Average visual control (N=8):
Experiment 1
Average visual control (N=8):
Response (idem)
Stimulus (% deviation from midpoint)

11. Average auditory (N=12):
Experiment 1
Average auditory (N=12):
Distributions of x-cross sections
Response (idem)
Stimulus (% deviation from midpoint)

12. Bias Variability Distributions of responses for stimuli: Experiment 1
-13.5
Distributions of responses for stimuli:
Bias
Variability

13. Experiment 1

14. Genuine perceptual effects or artifacts of the method?
Experiment 1
Genuine perceptual effects or artifacts of the method?
The participants’ visuospatial report is an accurate reflection of their mental representation.
SDT: distribution of responses == probability distribution, given the amplitude of a stimulation, that it originated from the stimulus in question. -5
Response (% deviation from midpoint)
Probability

15. Performance predictions in a 2AFC task (D = 4%):
Experiment 1
Performance predictions in a 2AFC task (D = 4%):

16. Experiment 2
Method
Each trial consisted of 2 1-sec sequences of 3 tones with D = 4% (40 msec):
1 sec D
Task: to indicate whether in the 2nd sequence compared to the 1st, the middle tone was played earlier (left button) or later (right button).

17. 11 pairs chosen to highlight the triple-U pattern:
Experiment 2
Presented in a random order, order of sequences in a pair counterbalanced.
150 repetitions per pair.
10 blocks of 11 pairs x 15 repetitions, in ~4 1-hour sessions.
13 participants (11 from Exp.1, 2 new).

18. Experiment 2
Results
Predictions +/- SE (N = 12)
Data +/- SE (N = 13)

19. Conclusion
We have developed a visuospatial representation method to investigate the perception of temporal patterns which is:
Exhaustive
Bottom-up
Fast
Gives a direct access to the mental representation
Evidence for rhythmic categorical perception (1:1 ratio), generalizing previous findings (Clarke, 1987; Schultze, 1989; Desain & Honing, 2003):
to a task which does not involve rhythmic categorization (or quantization) via (1) the use of musical notation and (2) the explicit instruction to disregard expressive timing,
to participants who are not highly musically trained.
See also Gert and Ryota & Yoshitaka’s talks today!
Confirmed in a classic 2AFC experiment, validating the method

20. Psychophysics of timing in 3-tones sequences:
Conclusion
Psychophysics of timing in 3-tones sequences:

21. Thank you!