Social norms, social approval,  social interaction Readings

Social norms, social approval, social interaction
Social norm: Rule of behavior enforced through l fb h
d h
others’ approval or disapproval
• Nyborg and Rege (2003, JEBO; sections 3‐5 cursory reading only)
• Akerlof (1980)
• Lindbeck (1997)
• See also: Nyborg and Rege (2003, PC)
Social approval matters
• Rege and Telle (2004, JPub Ec):
– One‐shot public good game; four treatments:
– Approval (non‐anonymity)/non‐approval
– Associative (“community”)/non‐associative
• Results:
– Weak evidence: associative language increases contributions
– Strong evidence: identification/indirect social approval increases contributions
Rege & Telle: Social approval matters
A social norm interpretation of ’warm glow’
• i cares about private and public goods, and social approval:
Ui = u(xi) + v(G) + si
where si = social approval
Assume gi (i’s contribution) discrete: 0 or 1
Contributor meets contributor: Gives social approval K
Non‐contributors: neither receive nor give approval
Expected social reward si in a random social encounter:
Expected social reward s
in a random social encounter:
si = giKa
 {0,1}
gi where a = share of contributors.
• E.g.: – If a = 0, si = 0 for gi = 1
– If a = 1, si = K for gi = 1.
• Social approval for contributions: increasing in the share of contributors. Contributing to get social approval
Ui = u(xi) + v(G) + si
si = giKa
a = (∑j g j)/N
N = population size i’s budget constraint
Y = x i + g i G = G0+∑j g j
G0 = public sector supply Assume that g i = 0 would be optimal for Homo Oeconomicus (G0 sufficiently large). Then, with preferences in (1), the only reason to contribute is to gain social approval.
Ui = u(Y) + v(G‐i)
(G‐i = G0+∑j≠ i g j )
If gi=0: Ui = u(Y‐1) + v(G‐i +1) + Ka
If gi=1: Will contribute if
[u(Y‐1) + v(G‐i +1) + Ka]‐ [u(Y) + v(G‐i)] > 0
v(G‐i +1) ‐ v(G‐i) + Ka > u(Y) ‐ u(Y‐1) 2
Social approval vs. impure altruism
• Contribute if public good gain plus social reward > lost cons. benefits
v(G‐i +1) ‐ v(G‐i) + Ka > u(Y) ‐ u(Y‐1) • Impure altruism: if public good gain plus warm glow benefits > lost cons. benefits
• Difference: with social approval, – Value of the private good (”warm glow”) depends on others’ behavior a > [u(Y) ‐ u(Y‐1) ‐ v(G‐i +1) + v(G‐i)]/K
• An increase in a can make i prefer to contribute
– Makes multiple equilibria possible
• Also:
– Requires observability by others (non‐anonymity) Nash equilibria
• If K is large enough, a =1 is a Nash equilibrium
– Contributing gives high social rewards, since there are many rewarders: A social norm for contributing is being enforced
– Public good supply: G = G0 +N
– Given everyone else’s strategy, contributing is the individually optimal strategy.
• a = 0 is also a Nash equilibrium:
– Contributing gives no social rewards, since there are no rewarders: No enforced social norm for contributing
– Public good supply: G = G0
– Given everyone elses’ strategy, the individually optimal strategy is to not contribute.
• a = a* is also an (unstable) Nash equilibrium – where a* is the share of contributors making i exactly indifferent.
– That is: v(G‐i +1) ‐ v(G‐i) + ka* = u(Y) ‐ u(Y‐1)
Coordination games
‐10, ‐10
‐10, ‐10
Two high‐speed drivers: Both prefer to drive at the same side of the road as the other. It doesn’t matter which side, as long as it’s the
Convention: Coordination equilibrium
Coordination games, cont.
Central 2,2
0, 0
0, 0
Self‐interested trading partners (material payoffs). Agree to trade at central market, both realize both are
close to local market: Where to go?
Local is better for both. But: Given that one expects the
other to go the the central market, it’s optimal to do the
same. Prisoners’ dilemma, reciprocal players
Cooperat Defect
Cooperate 4,4
5 2
(D,D): Each thinks the other is not being kind, thus does
not want to help: (D,D) is a fairness equilibrium.
(C,C): Each thinks the other is being kind, thus wants to help: (C,C) can be a fairness equilibrium.
Reciprocity can turn a PD into a coordination game
Social norms as cooperation equilibria
• Social norm models with multiple equilibria: n‐
person coordination games
• A social norm is a rule of behavior enforced through social sanctions • There exists a social norm: The economy is in a N h
Nash equilibrium where it is individually optimal, ilib i
i i i di id ll
i l
due to social sanctions, to obey the rule of behavior.
• There is no social norm: The economy is in a Nash equilibrium where it is not individually optimal to obey the rule of behavior. 4
Crucial: Approval depends on others’ behavior
• If social approval for following the norm is – increasing in others’ norm compliance: Multiple equilibria can arise (coordination game; ’good’ or ’viscious’ circles)
– decreasing in others’ norm compliance (status‐
seeking model): Unique equilibrium
– constant: Like impure altruism
Example: Feasibility of a generous welfare state
Lindbeck (1995, 1997), Lindbeck, Nyberg and Weibull (1999) Nash equilibria: 1. Few welfare recipients; strong norms against living on social security payments (high stigma);
i l
(hi h i
) high hi h
political support for the welfare state
2. Many (potential) recipients; weak norms against living on social security payments (little stigma for welfare recipients); low political support for the welfare state.
Example: Tax evasion
• Assume: – People care about social approval
– Government cannot observe evasion, trading partner can.
– Tax evaders do not disapprove of other evaders
– Tax payers do disapprove of evaders
Tax payers do disapprove of evaders
• If most others evade, the expected social sanction by evading will be small.
• If most others pay taxes, the expected social sanction will be large.
• Both evasion by (almost) everyone and evasion by (almost) everyone may be Nash equilibria.
The role of policy
• Assume: – Full evasion and no evasion are both Nash equilibria
– No evasion is Pareto superior to full evasion
• Potential role of policy:
Potential role of policy:
– Determining relative prices
– Determining the choice set
– Coordinating the economy in the Pareto superior NE
Public policy and social norms
• Nyborg and Rege (2003, JEBO): On the evolution of norms for considerate smoking behavior
• Non‐smokers – dislike passive smoking; spontaneous (involuntary) negative reaction
– Reaction stronger if less used to passive smoking
Reaction stronger if less used to passive smoking
• Smokers: – Dislike negative reactions from non‐smokers
– Trade the disutility of social sanctions against the disutility of smoking outdoors in cold weather.
• Two (stable) equilibria:
– One in which all smokers smoke indoors
– Another in which no‐one smoke indoors
The considerate smoking norm model
• Smoker i’s utility depends on negative reactions on indoor
smoking from non‐smokers (r) and inconvenience cost of
smoking outdoors (c):
U  (r  c) i
(r – c) = net gain of smoking outdoors rather than indoors
 i = 1: i
1: i smokes outdoors (considerate);
 i = 0: i smokes indoors (inconsiderate)
• Non‐smokers’ reactions depend on believed health effects of
passive smoking (k), and how used they are to passive smoking:
r   kh
 = Share of non‐smokers in the population
h = average consideration level among smokers
Smoking regulation
• Smoking regulation divides individuals’ time between a share R spent in the regulated zone (e.g. at work) and a share (1‐R) in the unregulated zone (e.g. private homes). Average consideration level:
h  R  (1  R )
 = average consideration level in unregulated zone. • Regulated zone: No inconsiderate smoking.
• Payoff from considerate behavior depends on R (via non‐smokers’ reactions) and other smokers’ behavior:
U ( i ;  )  ( k [ R  (1  R ) ]  c ) i
Nash equilibria
All others are
considerate in the
unreg. zone
k - c > 0
I'm inconsiderate 0
All others are
inconsiderate in
the unreg. zone
kR- c < 0
 R
• Assume that
• Then, there are three Nash equilibria: – One in which every smoker is considerate
– One in which no‐one is considerate
– One in which a share of smokers x’ are considerate (all are indifferent; corresponds to a mixed strat. NE). The impact of regulation
• Initial situation: All smokers smoke indoors
• Smoking regulation: All non‐smokers now spend some share of their time in smoke‐free air. – Get less used to passive smoking
– React more strongly
• Those
Those smokers who are most vulnerable to social smokers who are most vulnerable to social
sanctions will start to going outdoors
– Non‐smokers get even less used to passive smoking...
– Even more smokers go outdoors
• In the new equilibrium, every smoker smokes outdoors – even in the unregulated zone. 7
The tipping point
x  x 
Let x be the share of smokers who are considerate. Assume that the higher payoff gain of a strategy choice, the more smokers make that choice. Then x’ is a tipping point; x = 1 and x = 0 are stable equilibria, x’ is unstable.
Smoking regulation
• Initially: x = 0, R = 0 (no consideration, no regulation)
• Introduce smoking regulation R’ > c/k • x = 0 no longer a stable equilibrium; economy moves to x=1
• If regulation is removed after x > c/k: Economy will stay in x=1 (everyone is considerate).
x x 
The role of policy
• To secure such a move, the regulatory change must be large enough
– Otherwise, the first scared smokers will soon discover that sanctions are still not all that strong, and they will go back indoors. • If the smoking regulation is reversed, the economy will stay in the high consideration NE
economy will stay in the high consideration NE
– social sanctions enforce the norm
• Policy can affect behavior indirectly, through its effect on social norms
– even behavior which cannot be regulated directly • The role of policy here: Coordination device
Concluding remarks: Social norms
• Social interaction can produce n‐person coordination games
• If – people have preferences for social approval
– people sanction those who break a norm
– strength of sanction/approval is increasing in the share of norm followers
multiple equilibria may arise
• Norm equilibria may be stable
– even with costly compliance & no formal sanctions
• Possible role for policy: Coordination device