If you think your parents let your younger siblings get away with everything, you''re probably right. Parents punish older children more harshly – and they''re wise to do so. These are the conclusions of new research by Professors Joseph Hotz, Lingxin Hao and Ginger Zhe Jin published in the April 2008 issue of the Economic Journal.
The study – Games Parents and Adolescents Play – finds evidence that parents are more likely to withdrawal financial support from older siblings who either drop out of school – or in the case of girls, get pregnant – than their younger brothers and sisters who wind up in the same situations.
Further, the study presents analysis that supports such unequal treatment of children because more severe discipline of older children deters younger siblings from engaging in the activities for which they know their older siblings were penalised.
''My older sister always complains that she never got away with anything when she was growing up, and we all agree that my younger sister got away with murder'', says Professor Hotz, who grew up the middle child of five siblings. ''That''s the story of this paper.''
The researchers analyse parent-teenager interactions using the logic and mathematical tools of game theory. Their model assumes that parents want their adolescent children to avoid long-term negative consequences that can result from risk-taking behaviour, such as drinking, drug use, sexual activity and dropping out of school.
Teenagers, on the other hand, are assumed to value the short-term thrills of risk-taking behaviour while also wanting to avoid punishment.
The authors posit that parents need a reputation among their children for following through on threatened punishments. This reputation can change if parents do not punish their children after promising they will.
This reputation factor proves pivotal, as its predictions vary by the birth order of the children. According to the authors' theory, parents have an incentive to punish their first-born child if that child engages in risky behaviour in order to deter such behaviour by younger siblings.
First-born children, recognising that their parents are likely to be tougher on their transgressions, are generally deterred from being rebellious. But this deterrence motive for parents is predicted to wane as their younger children reach adolescence.
''Tender-hearted parents find it harder and harder to engage in “tough love” since, as they have fewer young children in the house, they have less incentive to uphold reputations as disciplinarians'', says Jin, herself an older sister and a parent of two.
''As a result, the theory predicts that last-born and only children, knowing that they can get away with much more than their older brothers and sisters, are, on average, more likely to engage in risky behaviour.''
''We became stricter with our son after our daughter was born'', Jin adds. To test their model, the researchers look for evidence of differential treatment of adolescent risk-taking by birth order in survey data from the National Longitudinal Study of Youth (NLSY), provided by the US Bureau of Labor Statistics.
They find two measures of adolescent rebellion and two measures of parental punishment. Dropping out of school and getting pregnant are interpreted as rebellion; not allowing a teenager to live in the family house and not financially supporting a teenager are interpreted as punishment. (Providing financial support is defined as parents paying half or more of a child's living expenses.)
The results of the researchers' analysis of the NLSY data are consistent with their model. The analysis shows that first-born children who dropped out of school or got pregnant are less likely to be living at home or receiving financial support from parents than younger siblings in the same situations.
Moreover, as predicted, younger siblings are more likely to engage in these behaviours, especially dropping out of school, than their older siblings.
''Parents often worry about how forceful of a stand to take in response to their older children's behaviour'', says Hao, the youngest of three sisters and a mother of one daughter. ''Our study finds that some parents are successfully using this strategy of influencing their younger children by stopping their older children''s risky behaviour.''
Despite being the youngest in her family, and therefore less likely to be disciplined, Hao says, ''I turned out to be pretty good.''
''Games Parents and Adolescents Play'' by Joseph Hotz, Lingxin Hao and Ginger Zhe Jin is published in the April 2008 issue of the Economic Journal.
Their research was supported by a grant from the National Institute for Child Health and Human
Development in the United States.