| Nonlinear Dynamics, Psychology, and Life Sciences, Vol. 2, Iss. 2, Apr, 1998, pp. 73-93 @1998 Society for Chaos Theory in Psychology & Life Sciences Effects of Random Noise and Internal Delay in Nonlinear Psychophysics Abstract: The effects of introducing second-order random noise on to parameters, so that they are unstable over time, and the effects of internal delay in a deterministic and therefore noise-free G recursion are compared. This is done by examining changes in the shape of the escarpment region which corresponds to the traditional psychometric function in sensation intensity or threshold experiments. Some of the grosser psychophysical response surface features are preserved, but only over a limited region of the parameter space. The system is robust against low noise and very brief internal delays, but will lose information and stability outside the region corresponding to low inputs and medium stability. This finding is compatible with what is reported on nonlinear cellular neural networks, for which a few analytical results on stability have been derived. Keywords: Key Words: psychophysics, ogive, delay, chaos, bifurcation |