Key Methods Used in Behavioral Genetics Research
Behavioral genetics is the study of the impact of genes of an organism on its behavior. It studies if the genes of a human being will reflect on his behavior like habits, mannerism, gestures, posture, etc. Through the interaction of heredity and growing up in the family environment etc., may have a specific composition of behavior that reflects the influence of genes.
Behaviour genetics is a branch of the study of psychology. Its other name is psychogenetics. This course had stated that abilities and disabilities must have an impact on nature and nurture. It is still a controversy. Let's see what are genetics and behaviour in psychology with their definitions and methods.
Definition of Behavioral Genetics
Behavior genetics is a branch of study that evaluates the role of genetics in the behavior of living organisms, which often includes the nature vs. Nurture debate. It is the consolidated form of behavioral genetics definition.
To explain them separately, the gene is a component of heredity, an element of DNA or RNA transferred from one generation to the next. They carry genetic information, particularly the sequence of amino acids for a protein. On the other hand, the physical and mental attributes of an organism or a human being are influenced by various factors. In simple words, we can say that the characteristics of a human being are influenced by nature and nurture.
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Origin of Genes and Behaviour
English scientist Sir Francis Galton (1822–1911) had started studying genetics and human behavior. He was the first person who coined the term nature and nurture. Nature is the internal genetic attitude of a human being. Whereas nurture is the environment supported to develop the personality. He started researching the families of excellent individuals. And he stated that few similarities were found between Charles Darwin and his cousin. Galton also made researchers on the genetics of twins for the first time. According to behavior genetics psychology, twins have more identical genes, but the behavior may differ. He's the person who gave the several statistical methods which are still in use.
In the 19th century, a British statistician and geneticist, Ronald Aylmer Fisher, explained the laws of inheritance stated by Greger Mendal. Fisher also explained how to use and implement those laws to influence attributes by environmental factors and multiple genes. Human behavior genetics research started in 1920. Then year by year, the researchers were modernized and found that several genes have much impact on Behavior and the results in depression, hyperactivity, intelligence, personality, mental disorders, autism, etc. In the book of behavioral genetics, Plomin has explained various theories and models to understand and to get a keen knowledge of genetics and human behavior.
Methods
Genetics and behavior in psychology have different methods proposed by other scientists. Even though all the ways may explain various attributes of an individual, each technique has some unique features and helps identify the complex traits.
Initially, the quantitative methods in genes and behaviour help to calculate or evaluate the net effect of the influence of environmental and genetic factors.
The following method is molecular behavior genetics. It helps to evaluate the genetic factors, and this method tries to find out if a special and unique gene belongs to that particular family or heredity. The study of molecular behavior genetics gives fruitful results in animals than in human beings.
The following method is selective breeding. It includes the identification of similar genes of various generations of a particular organism. It also helps to estimate the trait's high and low extremes.
Twin Method is an extract from the book of behaviour genetics. Plomin in his book proposed that the sharing of attributes may reflect in the behavior of different kinds of twins like identical, unidentical. Some genes may get injured, and the result may be reflected in both twins.
Another critical method is the adoption method. It is entirely in contrast to molecular behavior genetics. In this adoption method, a child is separated from his biological parents. So his behavior has been influenced by genes as well as environmental factors. This is the perfect example of nature and nurture impact.
These are the various methods available to explain the genes and behaviour of all organisms.
Conclusion
Hence the behaviour genetics is such a vast subject in which multiple variations and complex scenarios are available. The study of genes and behavior in psychology helps understand what genes are and how they relate to human behavior. The research can be done on various organisms, various kinds of people, different generations of a single individual, twins, etc.
FAQs on Behavioral Genetics: Understanding Genes and Behavior
1. What is behavioral genetics?
Behavioral genetics is a scientific field that studies the influence of an individual's genetic makeup on their behavior and the interaction between heredity and environment in affecting behavioral traits. It investigates how genes and environmental factors work together to shape differences in mood, personality, intelligence, and risk for psychiatric disorders. It does not suggest that genes are destiny, but rather that they create predispositions.
2. What is the importance of studying behavioral genetics?
Studying behavioral genetics is important for several reasons:
- It helps quantify the extent to which genetic and environmental factors contribute to individual differences in behavior.
- It provides insights into the biological pathways underlying both normal and abnormal behaviors, which can aid in developing treatments for psychiatric and neurological disorders.
- It helps us understand the complex interplay between nature (genes) and nurture (environment), moving beyond simplistic debates.
- It can identify genetic markers that may indicate a predisposition to certain conditions, allowing for early intervention strategies.
3. Can you provide an example of a behavioral trait influenced by genetics?
A classic example is intelligence, often measured as IQ. While no single “intelligence gene” exists, studies on twins and adopted children show a strong genetic component. Identical twins raised apart often have more similar IQ scores than fraternal twins raised together. However, genetics only accounts for a portion of the variance. Environmental factors like education, nutrition, and socioeconomic status play a crucial role in determining how that genetic potential is expressed.
4. What are the common research methods used in behavioral genetics?
Researchers use several key methods to investigate the genetic basis of behavior:
- Twin Studies: This method compares the similarity of a trait in identical (monozygotic) twins, who share 100% of their genes, with fraternal (dizygotic) twins, who share about 50%.
- Adoption Studies: These studies compare behavioral similarities between adopted children and their biological versus adoptive parents to disentangle genetic from environmental influences.
- Molecular Genetics Studies: These include techniques like Genome-Wide Association Studies (GWAS), which scan the entire genome of many individuals to find genetic variations associated with a particular trait or disorder.
5. How are complex behavioral traits different from simple Mendelian traits?
The key difference lies in the genetic architecture. Simple Mendelian traits, like Huntington's disease or cystic fibrosis, are monogenic, meaning they are controlled by a single gene. In contrast, behavioral traits like personality or intelligence are polygenic, meaning they are influenced by many genes, each with a small effect. Additionally, behavioral traits are multifactorial, as their expression is significantly shaped by complex interactions with multiple environmental factors, which is less prominent in simple Mendelian traits.
6. What is the main difference between behavioral genetics and epigenetics?
Behavioral genetics focuses on how variations in the DNA sequence itself (our genes) contribute to differences in behavior. Epigenetics, on the other hand, studies how behaviors and environmental factors can cause changes to the way your genes work without altering the DNA sequence. Epigenetic changes are modifications like methylation that can switch genes on or off, providing a mechanism for how nurture can shape nature.
7. Why is it incorrect to say a single gene 'causes' a complex behavior like aggression?
It is incorrect because complex behaviors are not determined by a single gene. They are the result of the combined action of hundreds or thousands of genes (polygenic influence), each contributing a tiny amount to the overall predisposition. Furthermore, these genetic predispositions are heavily moderated by gene-environment interactions. Factors like upbringing, social learning, and life stress play a massive role in whether a genetic tendency towards a certain behavior is ever expressed.
8. Are personality traits like introversion or extroversion determined by our genes?
Genes play a significant role in influencing personality traits like introversion and extroversion, but they are not the sole determinants. Heritability estimates from twin studies suggest that genetics can account for roughly 30-50% of the variation in these traits. This means that a substantial portion is also shaped by individual life experiences, social environment, and personal choices. Genetics might provide a baseline or a tendency, but environment and experience build upon it.
9. What are Turkheimer's Three Laws of Behavioral Genetics?
Psychologist Eric Turkheimer proposed three laws that summarize the findings of behavioral genetics:
- First Law: All human behavioral traits are heritable.
- Second Law: The effect of being raised in the same family is smaller than the effect of genes.
- Third Law: A substantial portion of the variation in complex human behavioral traits is not accounted for by the effects of genes or families.
The third law highlights the importance of the non-shared environment—unique experiences that happen to one individual but not their siblings—in shaping who we become.
