The tortuous trail of brain development
Poverty and trauma have an outsized influence on cognitive development says one of the largest study conducted in India.
Maturity, the thinking goes, comes with age. However, this journey from childhood to adulthood is uneven: some mental proclivity surface faster than others, some are more pronounced in girls, and poverty and trauma have an outsized influence on cognitive development, says one of the largest studies of its kind, spanning nearly 9,000 children and young adults from India.
The C-Veda
The study is part of a long-term project called the ‘Consortium on Vulnerability to Externalising Disorders and Addictions’ (C-Veda). The objective is to track individuals who have undergone testing for several decades and assess how biological and environmental factors impact their cognitive growth.
During the span of childhood to early adulthood, the development of the brain advances, and a vast network of neural connections is established throughout various regions of the brain. This connectivity significantly influences abilities such as temporarily holding chunks of information, called ‘working memory’ (for instance, memorising a phone number before writing it down) and ‘set shifting’ (iterating multiple ways to solve a puzzle). These skills are classified as executive functions. Another category of functions, called social cognition help mediate relationships.
A consortium of psychiatrists, neurologists, psychologists from India and the U.K., investigating the role of environment and genetics on brain development, analysed four kinds of executive functions: verbal working memory, visuo-spatial working memory, response inhibition (the ability to stop one task and begin another), set-shifting and two kinds of social cognition: faux pas recognition (inferring social cues) and emotion recognition (inferring another’s state of mind).
They report, in the April 2023 edition of the peer-reviewedAsian Journal of Psychiatry, that ‘working memory’ develops first, followed by inhibitory control and finally cognitive flexibility. However, certain abilities such as visual and verbal reasoning stabilised by late adolescence and didn’t rise as people aged, whereas cognitive ability and emotional cognition continued to develop even after adolescence, Eesha Sharma, the lead author of the study.
The studies, spanning a range of socio-economic groups, ages, urbanisation and gender, also found that children who manifested certain traits to a high degree outperformed their peers in that skill even as they aged, while other traits didn’t constitute a permanent advantage.
“Response inhibition has a ceiling. If you are low performing early on, you will catch up as you grow older. It was the other way, however, in verbal working memory. Those who did well in early childhood continued to significantly outperform their peers,” said Dr. Sharma, an assistant professor at the National Institute of Mental Health and Neurosciences, Bengaluru. “However, what all this means in the real world is a question that we are still analysing.”
Complex abilities
The more ‘complex abilities’ — response inhibition, cognitive flexibility, and emotion recognition — are “maximally impacted” by environments such as poverty or childhood adversity.
“No matter which ability you are looking at, children in wealthier households do better,” she said.
C-Veda plans to create brain maps of the participants in the study, in order to assess and compare their neurological development.
“If we can generate brain-development charts across ages, just like how there are charts for physical growth, it could be a valuable tool in schools and mental health assessments,” Dr. Sharma said.
