1. “Social Capital, Social Mobility” by: Peter Q. Blair

2. Motivations Progress benefits everyone (conventional wisdom) Reality: pockets of poverty still exist Research Question: What role does social mobility play in transforming 'poor' communities? Result: Increased social mobility has at best a positive or at worst a neutral effect on counteracting poverty.

3. Outline Model of Social Interactions in Poor Community (Fryer, Harvard U.) Understanding Cooperation Effects of Social Mobility Conclusions

4. Model: Social Interactions in Poor Community Agents endowed with talent 'Ө' by nature Agent invests in human capital 'h' and social capital 'c'  human capital: valued in both rich and poor community, e.g. college/high school education  social capital: valued in poor community only, e.g. native dialect, familial ties  subject to constraint: h+c=1 Community observes level of social capital investment by agent Agent and Community engage in social interaction game  modeled as infinitely repeated prisoner's dilemma game

5. Pay-off Matrix Parameters: 0 α; and β < 0

6. Understanding Cooperation Cooperation a Nash Equilibrium of Game  absent social mobility agents cooperate probability of remaining in community δ(h) = 1  assume social mobility probability of remaining in poor community 0≤ δ(h) < 1  δ '(h) < 0: increased 'h' indicates lower probability of cooperating probability of remaining in poor community [1- δ(h)] > 0  v_p(h,Ө): return to 'h' in poor community, given Ө  v_r(h,Ө): return to 'h' in rich community, given Ө  v'(Ө) > 0: return to 'h' varies positively with Ө in both communities  ρδ(h): discount factor of future utility -- require 0 < ρδ(h) < 1

7. Maintaining Cooperation Require Utility(C) ≥ Utility(D)  Result: δ (h) ≥ δ (h*): cooperation an equilibrium above a threshold probability of agent remaining in poor community  h ≤ h*: cooperation limits 'h' investment  c ≥ c*: cooperation requires minimum social capital investment (“litmus test of belonging”)

8. Effects of Social Mobility Social mobility requires probability of remaining in poor community to decrease in time  δ (h*)_t ≥ δ (h*)_t+1: h*_t+1 ≥ h*_t: poor community allows agents to invest in more human capital – increases utility of cooperating agents and counters the increased probability of defection c*_t+1≤ c*_t : poor community lowers social capital threshold for signaling community commitment

9. Effects of Social Mobility Depends on Marginal Utility (MU) of agent  Cases: Positive MU: greater investment in human capital (Positive Effect) Negative MU: no change in human capital investment (Neutral Effect) Zero Marginal Utility: no change in human capital investment (Neutral Effect)

10. Conclusion Social progress encourages human capital investment in poor communities Agents who value human capital investment benefit from increased social mobility Agents who value human capital investment, negatively, or not at all, neither benefit nor lose due to increased social mobility

11. Education is Key!