Groundbreaking research unpacks genetic factors linked to gaming habits

Motivation Behind the Study

With around 3 billion people worldwide engaging in video games, researchers are keen to explore the underlying factors contributing to this widespread pastime. This interest is amplified by the potential inclusion of gaming disorder in future psychiatric classifications, underscoring the need for a nuanced understanding of the roots of gaming behavior. This study, the first of its kind to use a longitudinal twin design, aimed to dissect the genetic and environmental components of gaming, observing how these influences evolve from childhood to late adolescence.

“I’ve studied problem gambling and also became interested in gaming, since it seems to share some features, but is much less investigated. I thought longitudinal data from a large twin register might teach us something about the gaming phenotype, and eventually, its relation to psychological health and addictive disorders,” explained study author Anders Nilsson, a licensed psychologist and PhD working at Centre for Psychiatric Research at the Karolinska Institutet.

Research Methodology

The study involved a massive sample of 32,006 twins from the ongoing Child and Adolescent Twin Study in Sweden. The researchers utilized a longitudinal approach, studying participants at three critical developmental stages: childhood (age 9), early adolescence (age 15), and late adolescence (age 18). The sample was almost equally divided between males and females and included monozygotic (identical) twins, who share all their genes, and dizygotic (fraternal) twins, who share about half of their segregating genes.

Parents were asked to report their children’s frequency of gaming, including both computer and TV gaming, with responses ranging from “never” to “almost daily.” The researchers then employed sophisticated statistical techniques to analyze these responses, focusing on the similarities in gaming behavior within twin pairs. This approach allowed them to estimate the relative contributions of genetic factors and shared environmental influences (factors that are common to both twins in a pair, such as family environment) to gaming behavior.

Key Findings: The Role of Genetics and Environment in Gaming

The researchers found that genetic factors accounted for a larger proportion of the variance in gaming behavior in males compared to females. This genetic influence was not static; it increased notably as boys grew older. Specifically, the genetic contribution almost doubled for males between the ages of 9 and 15, rising from 31.3% to 62.5%. For girls, however, the genetic influence on gaming behavior remained relatively stable across ages, ranging from 19.4% to 23.4%.

“The large difference between girls and boys was a bit surprising. If other types of screen activities would have been included, maybe we would have seen other results,” Nilsson told PsyPost.

Environmental factors shared by twins, such as family setting, played a more substantial role in influencing girls’ gaming habits throughout the ages. Interestingly, the influence of shared environment was quite pronounced for both boys and girls at the younger age of 9, but as boys aged, this influence diminished markedly, suggesting a decrease in family and common environmental effects on their gaming behavior. For girls, the shared environmental influence remained stable over time, indicating a more consistent external impact on their gaming activities.

The study also revealed notable differences in gaming frequency patterns between boys and girls. Boys tended to spend more time gaming at ages 15 and 18 compared to age 9. In contrast, girls showed a decrease in gaming frequency with age; a larger proportion of girls reported never gaming at age 18 compared to age 9. This divergence underscores the varying trajectories of gaming engagement between the sexes as they grow.

The findings provide evidence “that gaming, and what explains gaming (e.g. genes and environmental factors), is varying quite extensively depending on age and sex studied,” Nilsson explained. “For example, gaming among boys seem to be more explained by genes while environment plays a much larger role for gaming among females. But also that gaming is, as with virtually all other studied phenotypes, explained both by genes and environmental factors.”

Limitations and Future Research Directions

Despite its groundbreaking insights, the study has its limitations. One significant constraint was the reliance on parental reports, which may not always accurately capture the children’s gaming habits, especially as they grow into adolescence and gain more independence. The method of measuring gaming frequency was also somewhat broad, which might have oversimplified the complexity of gaming behavior.

“The measure of gaming is somewhat crude; the twins’ parents were asked about how often the twins were gaming, from everyday to less than every month. A more detailed account on hours spent could have rendered other results,” Nilsson said.

Looking to the future, researchers are keen to delve deeper into this field. They aim to better understand the relationship between gaming, disordered gaming patterns, and psychological health. An important aspect to explore further is how gaming behavior relates to other screen activities and whether the genetic and environmental influences on gaming overlap with those on other behaviors like social media usage.

“Hopefully, we will eventually get a better understanding of gaming and disordered gaming and how it relates to psychological health,” Nilsson said. But it “is important to note” that in the current study, “we studied gaming per se, not gaming disorder or other forms of problematic gaming.”

The study, “The genetics of gaming: A longitudinal twin study“, was authored by Anders Nilsson, Ralf Kuja‐Halkola, Paul Lichtenstein, Henrik Larsson, Sebastian Lundström, Helena Fatouros‐Bergman, Nitya Jayaram‐Lindström, and Yasmina Molero.