Figure 2.

Investment by individual 1 (blue) and 2 (red) in public (left column) and private (right column) goods, given a fixed total quantity of resources (x₁ + x₂ = 2), as one varies the fraction of those resources available to individual 1 rather than to individual 2. Dotted line in left column denotes total investment by both individuals in the public good. In the top panels, both place equal value on the public good (a₁ = a₂ = 0.6), whereas in the bottom panels, individual 1 places less value on the public good than does player 2 (a₁ = 0.4, a₂ = 0.8). Vertical grey lines demarcate zones that yield qualitatively different outcomes.