The incremental construction of the learning rules.

(a)–(c) The different stages in the construction of the learning rules. All panels feature a mathematical formulation of the rules at the given stage and a simulation of these rules. The reinforcements in those simulations, indicated by black dots, alternate between a fixed payoff of magnitude 20 and a fixed cost of −20. The Go weights G are depicted in green, the negative No-Go weights −N are depicted in red. The parameters used in the simulations were α = 0.300, ϵ = 0.443 and λ = 0.093. (d)–(f) Definition, visualization and properties of the nonlinear function fϵ.