by As a species, humans like to think that we are in complete control of our decisions and behavior. But just below the surface, how we think and behave are influenced by forces that are not under conscious control: our genes.
Since the 1950s, scientists have been studying the effects of genes on human health. This has led medical professionals, researchers and policy makers to support the use of precision medicine to personalize disease diagnosis and treatment, leading to faster improvements in patient well-being.
But the influence of genes on psychology has been ignored.
My research addresses 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 issues.
What do genes have to do with it?
Genetic conflict theory suggests that while our genes mix together to make us who we are, they retain markers that indicate whether they came from mom or dad. These markers prove that the genes cooperate or fight with each other as we grow and develop. Research into genetic conflict mainly focuses on pregnancy, since this is one of the few times in human development when the influence of different sets of genes can be clearly observed in a single individual.
Normally, maternal and paternal genes have different ideal strategies for growth and development. While genes from mom and dad eventually find ways to cooperate with each other resulting in normal growth and development, these genes take advantage of pushing fetal development to be a little more in line with what’s best to the parent from which they come. Genes from mom try to keep mom healthy and with enough resources left for another pregnancy, while genes from dad take advantage of the fetus taking all of the mother’s resources for itself.
When genes are not in harmony, however, undesirable outcomes such as physical and mental deficiencies for the child or even miscarriage can occur.
Although genetic conflict is a common occurrence, its impact in psychology has been largely ignored. One reason for this is that it is accepted that genetic cooperation is essential to the health and well-being of the individual. Another reason is that most human traits 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 pinpoint the unique influence of a single gene, let alone which parent it came from. Take, for example, depression. The likelihood of developing depression is not only influenced by 200 different genes, but is also influenced by environmental inputs such as childhood maltreatment and stressful life events. Researchers have also studied similar complex interactions for stress- and anxiety-related disorders.
Prader-Willi and Angelman syndrome
When researchers study genetic conflict, they typically focus on its link to disease, inadvertently documenting the impact of genetic conflict on psychology.
Specifically, researchers have studied 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 silenced—are associated with changes in behavior through studies do to people with Prader-Willi syndrome and Angelman Syndrome.
Prader-Willi and Angelman syndromes are rare genetic disorders that affect approximately 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 condition.
These syndromes develop in patients who lose one copy of a gene on chromosome 15 that is required for balanced growth and development. A person who inherits only the version of the gene from their father will develop Angelman syndrome, and a person who only inherits the version of the gene from their mother will develop Prader-Willi syndrome.
The physical hallmarks of Angelman syndrome include severe developmental delays, intellectual disabilities, trouble moving, trouble eating and excessive laughter. Physical hallmarks of Prader-Willi syndrome include reduced muscle tone, feeding difficulties, hormone deficiencies, short stature and extreme childhood overeating.
These syndromes represent one of the few cases where the influence of a single missing gene can be clearly seen. Although Angelman and Prader-Willi syndromes are associated with language, cognitive, eating, and sleep issues, they are also associated with clear differences in psychology and behavior.
For example, children with Angelman syndrome smile, laugh and generally want to engage in social interactions. These behaviors are associated with an increased ability to receive resources and investment from those around them.
On the other hand, children with Prader-Willi syndrome experience tantrums, anxiety and have difficulties in social situations. These behaviors are associated with increased hardship on mothers early in life, which may delay when the 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 investigating 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 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 baby is still in utero and helps to calibrate how reactive they will be to different social situations. Although this calibration of responses begins at a purely biological level in the womb, there are unique patterns of social behavior that influence everything from how we handle stress to our personality.
Since most scientists do not consider the impact of genetic conflict on human behavior, much of this research remains theoretical. Researchers have had to find similarities across disciplines to see how the biological process of genetic conflict affects 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 human biology makes us unique.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by: Jessica D. Ayers, Boise State University
Read more:
Jessica D. Ayers does not work for, consult with, share in, or be funded by any company or organization that would benefit from this article, and she has not disclosed any relevant connections beyond their academic appointment.
