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Formal modeling of cognitive bistability (e.g.[1][2]) is an interesting problem because a constant stimulus (e.g. the Necker cube) excites quasi periodic alternations between only two well defined perception states. Periodic stimulus–off switching (toff < 1 s, ton = 300 ms) was introduced by Orbach et al. [3] as experimental paradigm to get more insight into the underlying perceptual dynamics. Their Necker cube experiments showed a maximum of the percept reversal rate R at Rmax 36 min-1 and toff 200 ms which was confirmed by recent experiments [4]. Noest et al. [5] demonstrated with a low level neural activation model [6] that a bifurcation of the percept choice dynamics during the ambiguous-stimulus on-off switching dominates the statistics of the reversal time series. Our simulations based on a macroscopic (behavioral) dynamics model [7][8] (similar to [1]) support this finding and show that the measured R vs. toff-time characteristics can be fitted with only few model parameters: attention (= adaptive feedback gain) fatigue time constant = 1 – 2 s, feedback delay T = 40 ms, gain-noise power J. Synchronisation of attention fatigue induced self-oscillations (yielding inter-stimulus transition time TTr 4 – 5 T) with stimulus-onset induced percept bifurcation appears to determine the reversal rates and the toff-value at Rmax. A linear approximation allows for an estimate of the cognitive damping time constant (v ≈ 1 s) which by use of the Fluctuation-Dissipation theorem via Jdefines an index of cognitive inertia (suggested in [8]) as crucial parameter of the simulated dynamics. [1] Ditzinger, T., Haken, H. (1989). Oscillations in the Perception of Ambiguous Patterns. Biol. Cybern. ( 61) 279-287 [2] Huys, R,, Jirsa, V.K. (2010): Nonlinear Dynamics in Human Behavior. Springer Verlag, Berlin, Heidelber. [3] Orbach. J., Zucker, E., Olson, R. (1966). Reversibility of the Necker Cube: VII. Reversal rate as a function of figure-on and figure-off durations. Percept. Motor Skills (22), 615-618 [4] Kornmeier, J., Ehm, W. Bigalke, H., Bach, M. (2007): Discontinuous presentation of ambiguous figures: How interstimulus-interval durations affect reversal dynamics and ERP’s. Psychophysiology, 44, 552-560 [5] Noest, A.J., van Ee, R., Nijs, M.M., van Wezel, R.J.A. (2007) Percept-choice sequences driven by interrupted ambiguous stimuli: A low-level neural model. J of Vision 7, 1-14 [6] Amari, S. (1977): Dynamics of pattern formation in lateral-inhibition type neural fields. Biological Cybernetics vol. 27, 77-87 [7] Fürstenau, Norbert (2010). A nonlinear dynamics model for simulating long range correlations of cognitive multistability. Biol. Cybern., vol. 103. (3) 175-198 [8] Gao, J.B., Merk, I., Tung W. W., Billok V., White, K.D., Harris J G, Roychowdhury V P. (2006). Inertia and memory in visual perception. Cogn. Processing vol. 7 105-112 |
