A recent study that mapped the personality traits of thousands of twins and their families suggests that narcissistic behavior patterns are passed down from parent to child entirely through genetic inheritance, rather than through parenting methods. The study, published in Social Psychological and Personality Science, shows that an individual’s life experiences outside the home during childhood shape the remaining variations in this trait. These results have led to a major change in the way psychologists think about the origins of narcissism.
Narcissism is a personality trait defined by a sense of grandiosity, feelings of entitlement, and a strong urge to gain social status. People who exhibit high levels of narcissism often find early success in dating and leadership roles, projecting an initial confidence that others find attractive. At the same time, this personality aspect regularly leads to interpersonal conflicts, risky decision-making, and long-term organizational disruption. Because narcissistic tendencies remain very stable once formed during adolescence or early adulthood, psychologists are very interested in understanding how these traits develop in the first place.
Historically, popular psychology and academic theory alike have pointed to the family environment as the primary cause of the development of narcissism. According to the psychoanalytic model, narcissistic behavior appears as a protective mask to compensate for a cold, unloving parent. Learning theory suggests that when parents overestimate themselves or consistently put themselves on a pedestal, children develop an unrealistic view of themselves. Both of these frameworks dominate public discussions about narcissism. They are based on the largely untested assumption that a parent’s particular parenting style influences the development of a child’s personality.
Psychologist Mitya Bach of the University of Münster in Germany and her colleagues wanted to test the validity of this developmental assumption. The researchers noted that parents share both the environment and genetic material with their children, making it difficult to separate the influence of physical genetics from upbringing. To disentangle these factors, the researchers turned to the Extended Twin Families Study Design and analyzed broad patterns in family characteristics. Previous behavioral genetic studies have examined narcissism, but have relied on traditional twin models that have small sample sizes and fail to account for complexities such as parents choosing similar partners.
The study used data from Germany’s TwinLife project, a large-scale evaluation of twins and their families. The final sample included 6,715 identical and fraternal twins, their nontwin siblings, mothers, fathers, and romantic partners. This special family structure allows scientists to compare similarities in personality among relatives who share varying amounts of genetic material. Identical twins share nearly all of their DNA, while fraternal twins and typical siblings share about half of their segregating genetic sequences.
Participants completed a standardized psychological questionnaire designed to measure a number of narcissistic tendencies. Adolescents answered questions about their perceived leadership abilities, feelings of being special, and desire to control others. Adults responded to items assessing their desire for admiration, attention, and social prestige. The researchers surveyed participants across three specific age cohorts, collecting data from people aged approximately 15, 21, and 27.
By comparing survey scores for different types of family relationships, the team determined the proportion of narcissism that stems from different sources. They calculated the influence of inherited DNA, which researchers formally refer to as genetic variance. They also measured the influence of the shared environment, referring to influences jointly experienced by siblings living in the same household, such as family wealth and common parenting styles. Finally, the team evaluated the role of the non-shared environment. This includes a person’s unique experiences, such as a particular peer group, unique romantic partnerships, or personal workplace dynamics.
Researchers have found that about 50 percent of individual differences in narcissism are due to genetic factors. The remaining 50 percent comes from entirely non-shared environmental influences, meaning that the shared family environment contributes little to the development of the trait. Factors that siblings experience together, such as extensive parenting strategies or warmth provided by their mother or father, do not result in equal levels of narcissism. Identical twins were much more similar than dizygotic twins, indicating a strong biological basis.
Although parents and children did show similar levels of narcissism, the data revealed that this similarity was driven entirely by shared biology. Researchers found no evidence that parents transmit narcissism to their children through their actions or direct parenting methods. In fact, mathematical models suggest that there is a small negative effect on the environment, suggesting that highly narcissistic parents may create an environment that slightly interferes with traits in their offspring. Although the researchers note that this finding requires careful interpretation, it strongly contradicts the common belief that narcissistic parents shape highly narcissistic children through their parenting choices.
The researchers observed another pattern that contributes to family resemblance, a concept known as assortative mating. This refers to the tendency for people to choose romantic partners with similar characteristics to themselves. In this study, parents showed similar levels of narcissism to each other. This pattern contradicts the cultural idea that narcissistic people intentionally choose submissive or opposing personalities as romantic partners, slightly increasing the likelihood that their children will inherit these associated biological markers.
The relative influence of genetics and personal experience was consistent across different age groups. The study authors initially suspected that genetic factors played a larger role in the older cohort, as younger adults gained the autonomy to seek out environments that matched their genetic biological predispositions. The data showed no statistically significant differences between age cohorts. This indicates that the proportional contributions of biology and unshared experience are highly stable from adolescence to adulthood.
The study was based on self-report questionnaires, which could introduce bias if participants were not self-aware or answered in a way they considered socially acceptable. Such biases can artificially reduce mathematical estimates of actual family resemblance. Still, the authors note that this data limitation does not change their main conclusions. Narcissism is primarily prevalent in families through genetic inheritance, and not through the shared environment of the childhood home.
Buck et al. suggest that future research should focus on the experiences of the individuals who make up non-shared environments. Since parenting style shows little influence, psychologists need to investigate how peer networks, romantic relationships, and repeated advancements in the workplace can strengthen narcissistic tendencies. The researchers suggest studying how people respond to social rewards over time. These unique social interactions can interact with genetic predispositions to amplify a person’s behavior over time.
Scientists also need to identify the specific biological mechanisms by which genetic inheritance actually influences. The study authors recommend investigating how specific gene sequences affect hormone levels such as testosterone and the nervous system that processes reward and threat. Understanding how biological susceptibility to social status interacts with specific life events will fundamentally change the way psychologists approach narcissistic individuals in therapy, the workplace, and everyday relationships.
The study, “Genetics Causes the Prevalence of Narcissism in Families: An Extended Twin Family Analysis,” was authored by Mitja D. Back, Jana Instinske, Theresa Rohm, Marco Deppe, and Christian Kandler.
