BF - Genetic and Environmental Influences on Behavior Lesson

 

Genetic and Environmental Influences on Behavior

Examine the role of genetics in the development of behaviors.

Do you ever think about how you would have turned out if you'd been raised differently? Would you have the same taste in music, academic GPA, social habits, and athletic skills if you had grown up in another household? This is what some psychologists study. They want to understand the interacting effects of the environment and heredity on human behavior.

First, it's important to understand that every cell in your body contains genetic material that determined how you would be built. You received this genetic material from your biological parents - 23 chromosomes from each parent. Each of these 46 chromosomes contains little pieces called genes. Genes can be active or inactive; it's the active ones that create the proteins that make up your teeth, muscles, hair, bones, blood, and all the other building blocks that make you your own unique personality. Your personality and intelligence are determined by clusters of genes... but that isn't the whole story.  

Any two humans have genes that are 99.9% identical. So how is it possible that we find such vast differences amongst people? Even identical twins, who share the same chromosomes from the same sperm and egg, aren't perfectly identical in height, IQ, personality, and other traits. Psychologists who are interested in this question study epigenetics.

Have you ever worked out for a season? After a few months of hard work, your body changes. You're faster and stronger, with more defined muscles. Your body adapted to the environment that you subjected it to. Your genes work the same way. Just like you created harder muscles by putting them in that environment, certain environmental factors can "turn on" a gene, causing it to create a protein molecule that creates a characteristic in a human.

Imagine that you got the genes for being intelligent and hilarious, while your sister got the genes to be quiet and sensitive. It's possible that people might treat you differently and you might take different classes in school, enhancing these differences. You could end up very, very different because your environments enhanced your genetic predisposition.

In a study of identical twins, scientists found that if one twin developed schizophrenia (a mental disorder characterized by debilitating hallucinations), 50% of the time the other twin also developed the disorder. This was only the case about 15% of the time in non-identical twins. Clearly, neither genes nor the environment is completely in control of a human's destiny.

 

Correlation between Twins	Correlation of Sibling Traits

 

You could also imagine that identical twins with a genetic predisposition toward anxiety, if separated at birth and adopted by different families, these children's environments could "turn on" or "turn off" that anxiety gene, making the child more or less likely to have crippling anxiety as an adult. Life for a child in a stressful environment with an abusive parent or a lack of financial stability could activate the gene, while life for a child in a calm, loving environment could inactivate the gene.

In summary, genes and environment interact to create the person. You are a product of an interaction between the genes your parents provided and the environment in which you were raised.

 

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