Web Appendix for “ Habitual Voting and Behavioral Turnout ” by James H . Fowler

, ( ) 1 i t p I α ≤ − . Notice in equation (4) that the max condition applies to propensities below a certain cutpoint to keep them from falling below 0. It is easy to show that this cutpoint is α . Thus, change in the propensity due to inhibition is , 1 , ( ) ( ) i t i t p I p I α + − = if , ( ) i t p I α ≥ . Notice that the interval , ( ) [ ,1 ] i t p I α α ∈ − is not empty as long as the speed of adjustment is not too large: 1/ 2 α ≤ . In this interval there is no feedback since the magnitudes of change due to reinforcement and inhibition are equal: α α = .