As a species, humans like to think that we are completely in control of our decisions and behavior. But just beneath the surface, forces beyond our conscious control influence how we think and behave: our genes.
Since the 1950s, scientists have been studying the influences that genes have on human health. This has led medical professionals, researchers, and policymakers to advocate the use of precision medicine to personalize the diagnosis and treatment of diseases, leading to faster improvements in patient well-being.
But the influence of genes on psychology is overlooked.
My research focuses on how genes influence human psychology and behavior. Here are some specific ways psychologists can use genetic conflict theory to better understand human behavior—and potentially improve the treatment of psychological problems.
What do genes have to do with this?
The theory of genetic conflict states that while our genes merge to make us who we are, they retain markers that indicate whether they come from our mother or father. These markers ensure that the genes work together or fight with each other as we grow and develop. Research into genetic conflict has focused primarily on pregnancy, as it is one of the few times in human development when the influence of different sets of genes can be clearly seen in a single individual.
Normally, maternal and paternal genes have different ideal strategies for growth and development. While maternal and paternal genes eventually find ways to work together that result in normal growth and development, these genes benefit by aligning the fetus’ development somewhat more closely with what is optimal for the parent they came from. Maternal genes try to keep the mother healthy and with enough resources left for another pregnancy, while paternal genes benefit from the fetus taking all of the mother’s resources for itself.
However, when genes are unable to identify the cause, it can have undesirable consequences, such as physical and mental deficiencies in the baby or even miscarriage.
Although genetic conflict is a common occurrence, its influence has been largely overlooked in psychology. One reason for this is that researchers assume that genetic cooperation is necessary for the health and well-being of the individual. Another reason is that most human characteristics are controlled by many genes. For example, height is determined by a combination of 10,000 genetic variants, and skin color is determined by more than 150 genes.
The complex nature of psychology and behavior makes it difficult to determine the unique influence of a single gene, let alone which parent it came from. Take depression, for example. The likelihood of developing depression is influenced not only by 200 different genes, but also by environmental influences such as childhood abuse and stressful life events. Researchers have also studied similarly complex interactions for stress- and anxiety-related disorders.
Prader-Willi and Angelman syndrome
When researchers study genetic conflicts, they typically focus on their association with disease, thereby inadvertently documenting the influence of genetic conflicts on psychology.
Researchers have specifically examined how extreme cases of genetic conflict—such as when the influence of one set of parental genes is fully expressed while the other set is completely suppressed—relate to behavioral changes by studying people who have Prader-Willi syndrome and Angelman syndrome.
Prader-Willi and Angelman syndromes are rare genetic disorders that affect 1 in 10,000 to 30,000 and 1 in 12,000 to 20,000 people worldwide, respectively. There is currently no long-term treatment available for either disorder.
These syndromes develop in patients who are missing one copy of a gene on chromosome 15 that is needed for balanced growth and development. A person who inherits only the version of the gene from their father will develop Angelman syndrome, while a person who inherits only the version of the gene from their mother will develop Prader-Willi syndrome.
Physical features of Angelman syndrome include severe developmental delays, intellectual disability, difficulty moving, difficulty eating, and excessive laughing. Physical features of Prader-Willi syndrome include decreased muscle tone, feeding problems, hormone deficiencies, short stature, and extreme overeating in childhood.
These syndromes represent one of the few cases where the influence of a single missing gene can be clearly observed. Although both Angelman and Prader-Willi syndromes are associated with language, cognitive, eating, and sleep problems, they are also associated with marked differences in psychology and behavior.
For example, children with Angelman syndrome smile and generally want to participate in social interactions. These behaviors are associated with an increased ability to obtain resources and investment from those around them.
In contrast, children with Prader-Willi syndrome experience tantrums, anxiety, and have difficulty with social situations. These behaviors are associated with increased hardship for mothers early in the individual’s life, which may delay when their mother has another child. This would therefore increase the child’s access to resources such as food and parental attention.
Genetic conflict in psychology and behavior
Angelman syndrome and Prader-Willi syndrome highlight the importance of examining the influence of genetic conflicts on psychology and behavior. Researchers have documented differences in temperament, sociability, mental health, and attachment in these disorders.
The differences in psychological processes between these syndromes are similar to the proposed effects of genetic conflict. Genetic conflict affects attachment by determining the responsiveness and sensitivity of the parent-child relationship through differences in behavior and resource needs. This relationship begins to form while the child is still in the womb and helps calibrate how responsive they will be to various social situations. Although this calibration of responses begins on a purely biological level in the womb, it results in unique patterns of social behavior that influence everything from how we deal with stress to our personalities.
Because most scientists do not consider the influence of genetic conflicts on human behavior, much of this research is still theoretical. Researchers have had to find common ground across disciplines to see how the biological process of genetic conflicts influences psychological processes. Research on Angelman and Prader-Willi syndromes is just one example of how integrating a genetic conflict framework into psychological research can provide researchers with a way to study how our biology makes us uniquely human.
This article is republished from The Conversation, a nonprofit, independent news organization that brings you facts and reliable analysis to help you understand our complex world. It was written by: Jessica D. Ayers, Boise State University
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Jessica D. Ayers is not an employee of, an advisor to, an owner of stock in, or a recipient of funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond her academic appointment.