Plenty of parents blame themselves for their children’s bad behaviour. But now scientists claim toddlers throw tantrums because of their genes – and not because of their upbringing.
New research into identical and non-identical twins suggests genetics have a more important role to play than previously thought.
For the past 25 years it has largely been thought that the development of childhood aggression was down to learning from bad role models.
Previous studies have indicated it starts during infancy and peaks between the ages of two and four. However, scientists from the University of Montreal found there are substantial differences in both the frequency and rate of change in tantrums because of the ‘interplay of genetic and environmental factors over time’.
“The gene-environment analysis revealed that early genetic factors were pervasive in accounting for developmental trends, explaining most of the stability and change in physical aggression,” said Dr Eric Lacourse at the university.
“However, it should be emphasised that these genetic associations do not imply that the early trajectories of physical aggression are set and unchangeable. Genetic factors can always interact with other factors from the environment in the causal chain explaining any behaviour.”
So just because children throw tantrums when they are small, there is no reason why they cannot be better behaved in later life. The study, published in the journal Psychological Medicine, involved parents of twins born between April 1995 and December 1998 in Montreal, Canada.
It included genetically identical monozygotic twins who originated from the same embryo and non-identical dizogytic twins who developed in separate embryos. Mothers were asked to rate the physical aggression of their twins by reporting behaviour such as hitting, biting, kicking and fighting, at the ages of 20, 32 and 50 months.
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