In each of the following scenarios, determine whether the change in people’s behavior is the result of a nudge or a substantive change in economic incentives.
a. A country with a low birth rate decides to offer free public child care for kids under the age of five.
b. A nonprofit organization runs a highly publicized campaign offering teenage girls a very small symbolic reward (say, $5) for each week that they stay in school, come to support group meetings, and avoid pregnancy.
c. A country with a rapidly growing population levies steep fines on any family that has more than two children.
d. A government agency runs an ad on television informing women about low-cost birth-control options.