The ideal age of marriage, according to neuroscience

Those opposing the bill have argued that gender equity could be brought about by reducing the legal marriage age for males to 18. There is also the point of view that what’s required is the proper implementation of existing laws, rather than such changes. Then there is the stale argument that is often brought into any debate on appropriate ages in this country: the proposal to go by the age at which we are eligible to vote. The question raised is: “In a country where 18-year-olds can choose who their Prime Minister should be, why can’t they decide who they want to marry at age 18?"

So, what is the appropriate age for an individual to take a marriage decision?

Among all living beings, humans babies are the most under-developed at their time of birth. Most animals’ newborns can stand on their feet within few minutes of birth, and are ready to produce their own offspring within two or three years. Humans acquire reproductive capability once they attain puberty around 10-12 years of age. Several studies, including a notable one by the American Academy of Pediatrics, have found that boys and girls are now starting puberty earlier than previously recorded. This can be attributed to an increased body mass index among children, nutritional factors, and/or the hormone influences of their dietary intake.

Socially speaking, the age at which girls are typically expected to marry has long been influenced by their age of puberty. There is a patriarchal view in many societies that it is the divinely-ordained duty of a girl’s guardian to hand her over, chastity protected, to a husband. The sooner girls got married after attaining puberty, the earlier these so-called ‘protectors’ of their chastity could breathe sighs of relief. So the marriageable age for women in the 19th century was around 10 years. By 1940, it had increased to 12-14 years. By 1978, the marriageable age had moved up only to 15. Now, with the government’s decision to raise their marriage age to 21, the gap between a girl attaining puberty and getting married has widened a bit more. Is this decision to extend the time between a female’s achievement of reproductive ability and her being given legal reproductive rights a move in the right direction?

There are many studies that suggest teenage pregnancy poses a higher risk of reproductive health challenges. Evidence gathered by demographer Ann Blanc and others suggests that giving birth in adolescence is quite unsafe and maternal mortality after age 18 is far lower.

Apart from this crucial health fact, any decision on the age of marriage should be guided by our knowledge about the source of all human decisions: the human brain.

In the past few decades, the advent of magnetic resonance imaging (MRI) has offered a safe and accurate way to study the anatomy and physiology of people’s brains at all ages. So our knowledge of various brain systems, their interactions and their influence on a wide range of cognitive and emotional processes has grown substantially. The consistent theme that emerges is that different parts of the brain reach maturity at different ages and the adolescent brain is far from having matured. The reward systems of the brain, those that make the young seek such thrills of life as sex and speed, are usually mature by the age of puberty. Studies on humans and laboratory animals generally support the notion that adolescents are more sensitive than adults to rewards. During adolescence, this hyper-responsive reward system manifests itself in multiple ways, including in elevated levels of sensation seeking and risk taking.

Consider the prefrontal cortex, the system of the brain that has the ability to regulate emotions, control impulsive behaviour, assess risks and factor into decisions the consequences of choices. It is biological reality that the prefrontal cortex reaches maturity only by the age of 25. So, until the age of 25, the risk management and long-term planning abilities of the human brain do not kick into high gear.

In his article, ‘The Amazing Teen Brain’ in Scientific American, Jay N. Giedd, chair of the division of child and adolescent psychiatry at the University of California, San Diego, and a professor at the Johns Hopkins Bloomberg School of Public Health, reminds us of the significance of a mismatch between the maturation of networks in the limbic system, which drives emotions and gets turbo-boosted in puberty, and the maturation of networks in the prefrontal cortex, which occurs later and promotes sound judgement and impulse control.

If we believe that attaining reproductive capability and maturation of the brain’s reward systems are the only basis for the age of marriage, then humans are ready as soon as they hit puberty. But if we believe that marriage requires individuals to assume significant responsibility for their decisions, then they should wait till their prefrontal cortex is fully mature. If so, the minimum age for men and women to get married should be 25.

Biju Dominic is the chief evangelist, Fractal Analytics and chairman, FinalMile Consulting