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Who rules the roost? New research reveals tots play key role in shaping the home environment

Posted on 7 May 2024

Toddlers call the shots at home, according to new research, confirming what parents have long suspected.

The findings of the study show how genes and the environment act as a combined force.

In a study carried out by experts in child development at the University of York, researchers have found that pre-school children actively select, shape and create their own experiences to match their genetic tendencies. 

The researchers looked at how genes and the environment work together to shape the brain development of children between the ages of two and four. 

They found that rather than being passive recipients of the environment around them – such as the behaviour and likes and dislikes of their parents – they also had a strong say in creating their own experiences based on their inherited preferences and character traits. 

The researchers looked at early cognitive stimulation at home including talking, singing, nursery rhymes, books and engaging with toys and puzzles. They found that children drove decisions on which activities to focus on and how often to do them at least as much as their caregivers. 

Cements the theory

Professor Sophie von Stumm from the Department of Education at the University of York, said: “As many parents will know, small children are already very clear about what they do and don’t like and this study cements the theory that, even at a young age, children are actively shaping their experiences at home. 

“A child’s preferences and differences in character will evoke distinct reactions from their caregivers. For example, if a child enjoys reading they will sit and focus on a book, which is likely to motivate caregivers to read with them more and provide more books.

“The debate over whether a child’s character and abilities are down to nature or nurture is long-running, but our findings show how genes and the environment act as a combined force. Our study can also explain why even siblings growing up in the same house can differ so widely in their behavioural tendencies, emotional development, and learning abilities.”

First systematic study

The research, funded by the Nuffield Foundation, is the first systematic study of genetics and the environment and how they interplay in very young children. 

The study used data from the Twins Early Development Study, which followed over 15,000 families with twins born between 1994 and 1996 in England and Wales. Over the course of this longitudinal study, twins’ verbal and nonverbal cognitive development was assessed at different ages, including at two, three and four, via standardised testing and extensive parent and self-reports.


Lead author of the report, Dr. Alexandra Starr, a researcher in the Department of Education at the University of York, said: “We wanted to look at the early years because we know that children are already very different before they start school, and these differences in cognitive and socio-emotional development have important long-term consequences. Early differences grow and become greater as children get older, leading to a ‘snowball effect’.

“The early home environment is particularly important to brain development, we know so many outcomes in later life are related to this - from educational achievement, career success and income level to wellbeing and the ability to have stable relationships with others.”

Powerful method

To tease apart the factors that aid children’s development, the researchers used a powerful method called polygenic scores. Polygenic scores capture DNA variants that are passed on from parents to children and that can indicate how likely a person is to, for example, do well at school. The researchers tested interactions between polygenic scores for cognitive development and environmental factors. 

“If we understand how children’s differences come about in early life it could help to identify children in need of intervention as soon as possible”, added Dr Starr. “For example, we could use DNA to identify children at genetic risk of developing reading problems, and offer them early intervention before maladaptive behaviours, like avoiding books, manifest. Preventive measures have a greater chance of being successful when implemented early in life. 

“Polygenic scores are so powerful because they can predict traits at birth just as well as later in life, acting as an early warning system which could be of particular help for those children who are likely to struggle the most.”

Potential benefits

The study found that the early home environment contributes more to differences in children than genetic effects, but the researchers believe that in future even better genetic methods will be available. These will show that genetics and the environment contribute equally to the differences between children. 

“People tend to be mistrustful of genetic testing because they fear it will result in discrimination”, added Professor von Stumm. “Our study makes the case for more research on genetics, so that we can maximise the potential benefits of genetics and minimise their risks in the future, especially in the context of child development. 

“Currently we tend to diagnose conditions like dyslexia and reading disorders when children are already struggling and have fallen behind. The latest advancements in genetic testing could mean we may one day be able to help children avoid reading difficulties altogether because we can support them effectively before they experience any of the struggles that are currently associated with dyslexia.” 

The advances of genomic research bring ethical considerations and challenges that need to be addressed to ensure genomic findings can benefit individuals, families, education systems, and society at large.


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About this research

Gene-environment interplay in early life cognitive development is published here: