Figure 4.

Confirmatory simulations (see Methods) of the analytical solution of an accumulator model in which the sensory and feedback noise combine additively. The red line shows the result of the analytical calculation as expressed in Equation (21), wherein the sensory signal (a), magnitude of sensory noise (b), and the magnitude of feedback noise (σ) are varied. The black dots show the results of numerical simulation. The results approximate Weber's law well but for low reward magnitudes and high sensory noise (b).