File Name: influence of heredity and environment on child development .zip
- How Genes Influence Child Development
- Human Growth and Development
- Heredity, Environment and Intelligence
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Many aspects of human characteristics such as height and eye color are largely genetically determined. Psychology researchers, however, tend to be interested in dimensions that are relatively less determined by genetics—traits that subject more to environmental influences, such as how a person feels, acts, and thinks. Given that the degree of genetic determination appears to vary from one dimension to another e. For example, Javier has two biological daughters who share the same biological mother.
How Genes Influence Child Development
Many aspects of human characteristics such as height and eye color are largely genetically determined. Psychology researchers, however, tend to be interested in dimensions that are relatively less determined by genetics—traits that subject more to environmental influences, such as how a person feels, acts, and thinks.
Given that the degree of genetic determination appears to vary from one dimension to another e. For example, Javier has two biological daughters who share the same biological mother.
Both are tall, well mannered, and musically inclined. Despite these similarities, the older child appears socially reserved and quiet, while the younger one, who was born into the same family environment, seems more outgoing.
In addition, one of his children has been diagnosed with a learning disability while the other seems exceptionally well-functioning cognitively. How can these similarities and differences between the two children be explained? One may think, "Well, Javier is tall and he is also a talented musician himself, so these girls must have gotten these 'good genes' from Javier. And he is quite strict when it comes to disciplining his children, so that explains their good manners.
But why is the younger one so sociable—and what about her learning disability? Maybe she hasn't been read to as much as the older one has. The field of behavioral genetics aims at understanding the observable differences in a wide variety of human characteristics, typically by analyzing the contributions made by heredity and environment in the development of the characteristics in question.
Although the research in behavioral genetics is ideologically and methodologically diverse, it is fair to state that it often helps one theorize how much heredity and environment contribute to an observed outcome, and how various factors may interact with each other to create a particular outcome. At the root of such research endeavors lies what is called the nature-nurture controversy. What are the roles of heredity and environment in the development of various human characteristics?
The nature-nurture controversy deals with this perennial question. The works by several early philosophers are often viewed as marking the beginning of this controversy. They therefore took the nativist perspective that humans are born with certain cognitive tendencies. By contrast, the clean slate view, proposed in by the British philosopher John Locke , focuses instead on the role of the surrounding environment in describing human thoughts. Locke compared the human mind to a piece of blank paper without any ideas written on it, and he suggested that only from experience do humans draw reason and knowledge.
Following these diametrically opposed ideas, scientists have since extensively explored the roles of heredity and environment. Before describing such efforts in detail, it is useful to define relevant concepts. Nature refers to heredity: the genetic makeup or "genotypes" i.
Heredity may range from genetic predispositions that are specific to each individual and that therefore potentially explain differences in individual characteristics e. The notion of nature, therefore, refers to the biologically prescribed tendencies and capabilities individuals possess, which may unfold themselves throughout the course of life.
Nurture, by contrast, refers to various external or environmental factors to which an individual is exposed from conception to death. These environmental factors involve several dimensions. For example, they include both physical environments e. Also, environmental factors vary in their immediacy to the individual; they involve multiple layers of forces, ranging from most immediate e.
To complicate matters even further, the factors in each of these layers influence and are influenced by elements within and outside of these layers. For example, the kind of peers a child is exposed to may depend on his or her parents' view of what ideal playmates are like, the local government 's housing policies, and the history of race relations. Despite its nomenclature, the nature-nurture controversy in its current state is less dichotomous than commonly believed.
In other words, the term "nature-nurture controversy" suggests a polarization of nature and nurture; continuity and interaction, however, more aptly describe the central processes involved in this controversy. Therefore, it is not about whether either heredity or environment is solely responsible for observed outcomes.
Rather, it is more about the extent to which these factors influence human development and the ways in which various factors influence each other. For example, following the fifteen-person massacre committed by two boys at Columbine High School in Colorado in April , the media were flooded with people offering their interpretations of what drove these high school students to commit this heinous and violent act.
Some were quick to attribute the boys' actions to such environmental factors as inadequate parenting practices in their families and the violence prevalent and even glorified in the American media. Others, by contrast, were convinced that these boys were mentally ill as defined in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders and that their ability to make responsible judgments had been impaired, perhaps due to a chemical imbalance to which they were genetically predisposed.
Which argument is "correct," according to most researchers? Probably neither. Most theorists agree that both nature and nurture are intertwined and influence most aspects of human emotion, behavior, and cognition in some ways. Given the prevailing views in current psychology, most researchers would agree that the violent acts committed by these boys probably stemmed from an unfortunate interaction among various hereditary and environmental factors.
Researchers, however, may disagree on 1 the extent to which heredity and environment each influences particular developmental outcomes and 2 the way in which a mixture of hereditary and environmental factors relate to each other. In other words, the controversy involves the extent of contribution as well as the nature of interaction among a variety of genetic and environmental forces.
How do researchers address these issues? Since as early as the s, researchers have attempted to estimate the contribution of hereditary and environmental factors to various aspects of human cognition, by comparing pairs of individuals varying in genetic relatedness. These studies are often called kinship studies, and twin studies and adoption studies represent two of the most common types of such studies. They have been extensively conducted to estimate the heritability of a wide variety of human characteristics.
In traditional twin studies, monozygotic identical twins and dizygotic fraternal twins are compared in terms of their emotional, behavioral, and cognitive similarities. In the process of cell divisions upon formation of a zygote, sometimes the resulting cells fully multiply and produce two identical babies; they are called monozygotic twins, since they come from a single zygote and are genetic "carbon copies. By contrast, dizygotic twins develop from two separate zygotes, as a result of two eggs being fertilized by two sperms independently.
Consequently, the genetic profiles of the resultant babies are similar only to the extent that they share the same set of biological parents. By comparing the correlations of a particular dimension, such as intelligence test scores, between identical twins and those between fraternal twins , researchers can theoretically compute the relative influences of nature and nurture on the dimension.
For example, Sandra Scarr reported an interesting finding in the book Intelligence, Heredity, and Environment. She found a correlation for IQ test scores of. Some influence of heredity, therefore, is evident. If IQ scores were percent genetically determined, however, the correlation for identical twins would have been 1. In this example, therefore, heredity appears to play an important, but not definitive, role in explaining the determinants of what is measured through IQ tests.
In addition to these heritability estimates, researchers also study concordance rates: the rates at which both twins develop the same, specific characteristics. The absence or presence of a particular mental illness would be a good example. If both twins had clinical depression in all pairs examined in a study, then the concordance rate would be percent for this sample.
On the other hand, if all twins in a study had one individual with clinical depression and another with no depression, then the concordance rate is 0 percent.
Reportedly, concordance rate for clinical depression is reportedly about 70 percent for identical twins and about 25 percent for fraternal twins. This appears to demonstrate a sizable genetic contribution involved in the development of depression. Despite scholars' consensus that genetic contributions are not to be ignored, these correlational data are often believed to be exaggerated. Identical twins are genetically predisposed to a great deal of similarities, and, through a process known as reactive correlation, people around them tend to treat them similarly, which may help lead the twins to be similar beyond what their genetic profiles may warrant.
The correlation of. Identical twins encounter environmental experiences that are extremely similar to each other's, as the environment tends to react similarly to those who are genetically similar. As a result, for instance, adults and peers may treat identical twins similarly, and teachers may also develop similar expectations about these twins in terms of their emotional, behavioral, and cognitive functions. This similarity in environmental influences and expectations, therefore, may cause heritability estimates and concordance rates to be exaggerated.
Furthermore, the process of active correlation or niche-picking suggests the possibility that children's genetic predispositions cause them to seek particular environments, causing the differences in hereditary predispositions to be enhanced by the subsequent environmental exposure.
If a child has the genetic predisposition to enjoy cognitive challenges, for example, that may prompt the child to seek situations, friends, and activities that suit this particular predisposition—provided that such choices are offered to the child.
This child, therefore, may start out with a small genetically prompted inclination to want to use his or her "brains," but such a tendency would subsequently be magnified through environmental influences. Given the varying degrees of genetic similarities between identical and fraternal twins, these sources of confusion may theoretically become more consequential when twins grow up in the same family.
This is because twins reared in the same family are typically subject to the same resources, parenting philosophy, living environments, and so on. Their genetic predispositions, therefore, are most likely promoted—or inhibited—in similar ways. For example, if a pair of twins share the hereditary predispositions for musicality and their upper-middle-class parents own a piano and are interested in fostering musicality in these children, their musical potential will perhaps be cultivated in very similar ways.
Specifically, their parents will probably get the same or similar piano teacher s for them, and they will probably be encouraged to practice equally. Therefore, the genetic similarities between the twins are magnified by virtue of them growing up in the same household. How does one address these concerns? Adoption studies provide some answers. Compared to traditional twin studies, adoption studies are theorized to offer better alternatives for separating hereditary influences from genetic ones.
There are typically two variations in adoption studies: ones involving comparisons of identical twins reared apart and ones comparing the degree of similarity between adopted children and their biological and adoptive parents.
Identical twins reared apart share genetic patterns with each other, yet they do not share the same environmental experiences. Adopted children, by contrast, typically share with the rest of the adoptive family similar environmental experiences but do not share any genes with them. The advantage of adoption studies is that researchers can reasonably estimate the heritability by comparing the heritability estimates and concordance rates of pairs of individuals varying in genetic relatedness and in environmental distance.
A typical adoption study may involve, for instance, comparing the concordance rates for the following two pairs: a child and her biological parent shared genes but not environments versus the same child and her adoptive parents shared environments but not genes.
Though the estimates of hereditary influences are generally lower in adoption studies than in twin studies, adoption studies provide results that are largely consistent with twin studies. In a study, Sandra Scarr and Richard Weinberg found that the IQ scores of adopted children showed higher correlations with the IQ scores of their biological parents than with those of their adopted parents.
Similarly, John Loehlin, Lee Willlerman, and Joseph Horn demonstrated through a study that in the area of clinical depression, adopted children tended to have much higher concordance rates with their biological relatives than with their adoptive relatives.
Still, many scholars argue that heritability may be overestimated in these studies. First, the reactive and active correlations discussed earlier would occur, to a degree, even if the twins were reared separately, as the twins share all of the hereditary predispositions. Second, one must also examine the possibility that parents may systematically treat their adoptive children differently than they do their biological children, which may explain the less-than-expected resemblance between children and their adoptive parents.
Given that biologically related individuals tend to share greater hereditary similarities, it is fair to state that heritability estimates may be thrown off by environmental effects induced by particular genetic predispositions. As illustrated so far, most psychology researchers are in agreement that heredity and environment both play significant roles in the development of various human traits. Researchers may disagree, however, on the extent to which heredity and environment contribute to the development of a particular dimension, and on how various factors may affect each other to create a certain human characteristic.
Neither heritability estimates nor concordance rates provide useful information on the latter type of disagreement: how various hereditary and environmental factors interact with each other to result in a particular characteristic. Mental health , education, and applied psychology researchers are especially concerned about optimizing the developmental outcomes among people from all backgrounds.
Human Growth and Development
Learn about how genetics play a powerful role in the development of a child of heredity, but environmental factors such as nutrition can also have an effect.2.
Heredity, Environment and Intelligence
Biological factors can play a particularly important role in early development. These factors influence a child in both positive and negative ways. They can affect children throughout their development, particularly during critical times such as the prenatal period and early childhood. Biological factors include genetic influences, brain chemistry, hormone levels, nutrition, and gender. Here is a closer look at nutrition and gender and how they affect development.
What determines how a child develops? While it is impossible to account for each and every influence that contributes to who a child eventually becomes, what researchers can do is look at some of the most apparent factors. These include things such as genetics, parenting, experiences , friends, family, education, and relationships.
Today, researchers generally agree that heredity and environment have an interactive influence on intelligence. Many researchers believe that there is a reaction range to IQ, which refers to the limits placed on IQ by heredity. Heredity places an upper and lower limit on the IQ that can be attained by a given person.
Essential Psychology pp Cite as. The interaction of a biological structure with an environment in which to function is a necessary prerequisite for the production of behaviour. Without a biological structure no behaviour is possible; without an environment which provides the stimulation and the context, no response can be displayed.
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The CTET exam is one of the very popular exams among the aspirants. Those who are aspiring to get a prestigious job as a teacher undergo this exam. Lakhs of candidates every year appear for this exam and give their best. Aiming to become a teacher? These 2 parameters define how we grow and how we turn out to be. It is also often debated that which factor influences more. Heredity is the science where we study the impacts of genetic factors on our behavior and development.
While there are many nuances to the nature vs. To briefly touch on the nurture side of the conversation, our environment — i. So, in spite of our desire to turn the nature vs. As we all know, genes from our parents influence everything from height, weight, eye color, and other physical characteristics, to behavioral patterns in achievement, intelligence and motivation. Typically, this means that the resulting embryo contains 46 chromosomes, which are the DNA molecules that house genetic information. These instances can lead to babies born with disabilities and conditions such as Down syndrome, characterized by an extra 21 st chromosome, or trisomy For children and students with Down syndrome, the effects on learning can vary widely and specialized education techniques are often necessary.
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It is universally agreed that we must pay attention to height when we want to estimate a child's physical development. But in order to make the right use of this.
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Появилась вторая пара, с детьми, и шумно приветствовала соседей. Они болтали, смеялись и троекратно целовали друг друга в щеки. Затем подошла еще одна группа, и жертва окончательно исчезла из поля зрения Халохота. Кипя от злости, тот нырнул в стремительно уплотняющуюся толпу. Он должен настичь Дэвида Беккера. Халохот отчаянно пытался протиснуться к концу улочки, но внезапно почувствовал, что тонет в этом море человеческих тел. Со всех сторон его окружали мужчины в пиджаках и галстуках и женщины в черных платьях и кружевных накидках на опущенных головах.