As a species, humans like to think we have complete control over our decisions and behaviors. But just below the surface, forces beyond our conscious control influence how we think and act: our genes.
Since the 1950s, scientists have been studying the effects of genes on human health. This has led medical professionals, researchers, and policymakers to advocate for the use of precision medicine to personalize disease diagnosis and treatment, leading to faster improvements in patient well-being.
However, the impact of genes on psychology has been ignored.
My research looks at 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 advance the treatment of psychological problems.
So what do genes have to do with it?
The genetic conflict theory suggests that, despite the combination of genes that make us who we are, they retain markers that indicate whether they come from our mother or our father. These markers cause genes to cooperate or fight with each other as we grow and develop. Research on genetic conflict focuses primarily on pregnancy, because it is one of the few times in human development when the effects of different sets of genes can be clearly observed in an individual.
Typically, maternal and paternal genes have different optimal strategies for growth and development. While maternal and paternal genes eventually find ways to cooperate with each other resulting in normal growth and development, these genes benefit by ensuring that fetal development is a little more in line with what is best for the parent they came from. While maternal genes work to keep the mother healthy and leave enough resources for another pregnancy, paternal genes benefit the fetus by using all of the mother’s resources for itself.
However, when genes do not reconcile, unwanted outcomes such as physical and mental disabilities in the baby and even miscarriage may occur.
Although genetic conflict is a normal occurrence, its impact has been largely ignored in psychology. One reason is that researchers assume that genetic cooperation is essential to an individual’s health and well-being. Another reason is that most human traits are controlled by many genes. For example, height is determined by the combination of 10,000 genetic variants, and skin color is determined by more than 150 genes.
The complexity of psychology and behavior makes it difficult to pinpoint the unique effects of a single gene, or even which parent it comes from. Take depression, for example. The likelihood of developing depression is influenced not only by 200 different genes, but also by environmental inputs such as childhood maltreatment and stressful life events. Researchers have also examined similar complex interactions for stress- and anxiety-related disorders.
Prader-Willi and Angelman syndromes
When researchers study genetic conflict, they often focus on its connection to disease and inadvertently document its impact on psychology.
Specifically, the researchers examined people with Prader-Willi syndrome and Angelman syndrome to see how extreme examples of genetic conflict (for example, when the effects of one parental gene group are fully expressed while the effects of the other group are completely silenced) were associated with changes in behavior.
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 for either condition.
These syndromes develop in patients who are missing one copy of a gene on chromosome 15 that is necessary for balanced growth and development. Someone who inherits only the version of the gene from their father develops Angelman syndrome, while someone who inherits only the version of the gene from their mother develops Prader-Willi syndrome.
Physical symptoms of Angelman syndrome include major developmental delays, intellectual disabilities, difficulty moving, difficulty eating, and excessive smiling. Physical symptoms of Prader-Willi syndrome include decreased muscle tone, feeding difficulties, hormone deficiencies, short stature, and childhood overeating.
These syndromes represent one of the few examples in which the effect of a single deficient gene can be clearly observed. Both Angelman and Prader-Willi syndromes are associated with language, cognition, eating, and sleep problems, as well as marked differences in psychology and behavior.
For example, children with Angelman syndrome smile, laugh, and generally seek out social interactions. These behaviors are associated with an increased ability to obtain resources and investments from those around them.
On the other hand, children with Prader-Willi syndrome experience temper tantrums, anxiety, and have difficulty in social situations. These behaviors are associated with increased challenges for mothers early in the individual’s life, potentially delaying the mother’s ability to have another child. Therefore, the child’s access to resources such as food and parental attention increases.
Genetic conflict in psychology and behavior
Angelman syndrome and Prader-Willi syndrome highlight the importance of studying the impact of genetic conflict 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 influences attachment by determining the sensitivity and responsiveness 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 to calibrate how much they will respond to different social situations. Although the calibration of these responses begins on a purely biological level in the womb, it results in unique patterns of social behavior that affect everything from how we cope with stress to our personalities.
Much of this research is still theoretical, as most scientists do not consider the impact of genetic conflict on human behavior. Researchers have had to find cross-disciplinary parallels to see how the biological process of genetic conflict affects psychological processes. Studies on Angelman and Prader-Willi syndromes are just one example of how integrating the genetic conflict framework into psychological research can provide researchers with a way to examine how our biology makes us uniquely human.
This article is republished from The Conversation, a nonprofit, independent news organization that brings you facts and trusted analysis to help you understand our complex world. By Jessica D. Ayers Boise State University
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Jessica D. Ayers does not work for, consult, own stock in, or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond her academic appointment.