Trueman Chap5

Trueman Chap5 - Chapter 5 Human Development THESE NOTES ARE...

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Chapter 5 Human Development THESE NOTES ARE NOT A SUBSTITUTE FOR READING THE TEXT OR COMING TO CLASS Genetic Principles Heritability Some traits are easily traced to a single gene. An example of such a trait is Huntington’s Disease. There are many others.
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Genetic Principles Heritability But even traits traced to a single gene may be strongly environmentally influenced. An example of this kind of gene is PKU. PKU causes profound mental retardation, but only if the affected person’s diet includes foods containing a certain enzyme. If the person with the PKU gene is kept on a strict diet for the first two decades of life, he will have normal intelligence. Genetic Principles Heritability Many characteristics and conditions of interest to psychologists cannot be traced to a single gene. Mental processes and behaviors
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develop through complex interactions of the influences of genes and environment. In the case of traits such as addiction, personality characteristics, and intelligence, it is meaningless to ask if the trait depends solely on heredity or environment. Genetic Principles Heritability The concept of heritability helps us to rephrase the question to make it more useful. Does a difference in behavior or outcome depend more on differences in genetic make-up or differences in environment? Heritability is an estimate of the variance in a population that is due solely to heredity. If we could somehow make the environment the same for all individuals, the
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differences we would see would then be attributable to genetic differences. Genetic Principles Heritability Heritability is measured from 0 to 1. 0 means that almost none of the variance in the trait in due to heredity – what religion a person practices has no basis in heredity. 1 signifies that variance in the trait is due entirely to heredity. If you have Huntington’s Disease or not will depend solely on whether you get the gene. Genetic Principles Heritability Many researchers have worked on the problem of heritability. It is difficult to know the exact degree
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of genetic influence because: The environment can start to impact an individual right from conception (a mother’s lifestyle and nutrition affect the growing fetus). Environments are hard to “standardize” or make identical (except in the laboratory, perhaps). Genetic Principles Heritability Genetic factors contribute to variations in almost all behaviors and processes of interest to psychologists. Yet there are good reasons to suspect an overestimation of heritability in psychology research due to the difficulties involved in studying humans in diverse environments.
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We need more evidence before we can confidently describe the role of heredity in forming human potential and personality. Genetic Principles
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Trueman Chap5 - Chapter 5 Human Development THESE NOTES ARE...

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