The global recession is enough to put a strain on many family finances. But genetic science is suggesting that some moms feel the strain more, and are more likely to practice harsh parenting.

The study, published in the journal Proceedings of the National Academy of Sciences, reveals that difficult economic conditions may lead to mothers engaging in harsh parenting, such as shouting or hitting children. But it is more apparent in mothers who carry a particular gene variation.

Researchers at New York University, Columbia University, Princeton University and Pennsylvania State University’s College of Medicine, analyzed data from the Fragile Families and Child Wellbeing Study (FFS). This a population-based cohort study across 20 large US cities of around 5,000 children born in the years 1998-2000.

Following birth, the mothers of the children were interviewed when their child was at 1, 3, 5 and 9 years of age. The researchers collected data on harsh parenting when the children were at 3, 5 and 9 years of age, and at age 9, saliva DNA samples were collected from 2,600 children and their mothers.

The harsh parenting data was gathered using the Conflict Tactics Scale. Five areas measured psychological harsh parenting, such as shouting and threatening, while five areas measured corporal punishment, such as slapping and spanking.

The researchers compared this data with measurements of economic conditions in the 20 large US states where the mothers lived. This data included details on monthly unemployment rates.

Results from the analysis revealed that harsh parenting in the mothers who were studied was significantly linked to increases in a city’s unemployment rate and declined consumer confidence in the economy.

The study authors say that from this, they believe it was the “anticipation of adversity,” or the fear of being unemployed due to poor economic conditions, that led to harsh parenting, rather than poor economic conditions in general.

Dohoon Lee, assistant professor of sociology at New York University, says:

It’s commonly thought that economic hardship within families leads to stress, which, in turn, leads to deterioration of parenting quality.

But these findings show that an economic downturn in the larger community can adversely affect parenting – regardless of the conditions individual families face.”

From this, the researchers analyzed whether the responses were determined by the genetic make-up of the mothers, by looking at the brain’s dopaminergic system – the area that helps regulate emotional and behavioral responses to surrounding environments.

They particularly focused on the DRD2 Taq1A single nucleotide polymorphism (SNP) – small changes in a person’s genetic code in a specific location of the brain. The DRD2 Taq1A genotype controls the synthesis of dopamine, a chemical that regulates behavior in the brain.

The researchers say previous studies have revealed that people who possess one T allele – known as the “sensitive” gene – for this SNP are more likely to show aggression compared to those without the sensitive gene.

The study showed that around 50% of the mothers surveyed possessed the T allele.

The results revealed that mothers who were in possession of the T allele were much more likely to engage in harsh parenting in deteriorating local economic conditions and areas with decline in consumer confidence.

However, the researchers say that mothers without the T allele showed no such changes under worsening economic conditions.

Additionally, when economic conditions were improving, the researchers found that mothers with the T allele were less likely to engage in harsh parenting compared to mothers without the T allele.

The researchers say this finding is significant as it shows that the effect of genes on people’s behavior could depend on the quality of their environment.

Irwin Garfinkel, co-author of the study and professor of contemporary urban problems at the Columbia University School of Social Work, says:

This finding provides further evidence in favor of the orchid-dandelion hypothesis that humans with sensitive genes, like orchids, wilt or die in poor environments, but flourish in rich environments, whereas dandelions survive in poor and rich environments.”