Figure 1.

Typical error curves generated by simulating the two-state model, equation 2.1, with (A) ${\sigma }_w^2=1\times {10}^{-4}$ and ${\sigma }_v^2=3\times {10}^{-4}$, (B) ${\sigma }_w^2=5\times {10}^{-4}$ and ${\sigma }_v^2=15\times {10}^{-4}$, and (C) ${\sigma }_w^2=10\times {10}^{-4}$ and ${\sigma }_v^2=30\times {10}^{-4}$. Thin gray lines depict individual realizations, and thick black lines depict average error curves. External perturbations are 0 in trials 1–30 and 1 in trials 31–100 (shaded areas).