Irrationality makes society as a whole better off as long as the psychological benefits minus the material costs are positive: Psychological Benefits – Material Costs > 0. Irrationality makes the individual better off under far less stringent conditions: Psychological Benefits – p * Material Costs > 0. where p is the probability of casting the decisive vote. If p = 0, irrationality is utility-maximizing as long as there are any psychological benefits: Psychological Benefits > 0
