PASSAGE 2

The Impact of Environment on Children

As far as a child’s growth is concerned, it would be out of the question to identify each and every influence that determines who a child becomes.

Our concern is with some of the most critical factors such as genetic features, experiences, friends, family relationships and schools to help us decipher the influences that contribute to a child’s development.

These influences have often been thought of as being analogous to building blocks.

While most people tend to have the same basic building blocks, these components can be put together in an infinite number of ways.

How much of who you are today is ascribed to your genetic inheritance, and how much is a result of your experiences of a lifetime?

In philosophy, psychology and education, the issue of nature versus nurture has been debated for centuries.

Generally, the given rate of influence to children is 40% to 50%, and it may refer to all of the siblings of a family.

Then are we shaped by our genetic background or the environment?

Today, the argument arrives at a reasonable conclusion that both genes and the environment play important roles in determining a child’s growth.

A child’s personality may have natural inclinations, but external ingredients such as education can affect how he behaves.

From the earliest moments of life, the interaction of heredity and the outside world has started to define who children are and who they will become.

While the environment has few influences on biological processes related to genes and proteins, it does affect whether children will express the genetic directions.

The dynamic relationship of nature and nurture is persistent and lifelong instead of occurring occasionally.

So how exactly do different types of environments, shared and non-shared, affect children’s development?

Shared environments, also known as common environments, refer to environmental elements that are making siblings in a family more similar to one another.

Specifically, shared parenting styles, shared peer groups, shared socio-economic status and so on are all environmental influences that would be shared by children within any specific family.

Actually, strong evidence for shared environments’ effects on individuals’ behaviours has not yet been detected, particularly those measured in adults.

One possible reason discussed is that shared environmental effects play a significant role in children and adolescents, but these effects during that period would be decreased in the future life span.

Advancement in modern behaviour genetic methods has made it possible to recognise the significance of shared environments and distinguish familial and non-familial sources of shared environmental features.

It may be concerned with all siblings in a family, but the influence rate accounts for less than 10%.

It was not until a century ago, with the advent of quantitative genetic study, that the importance of non-shared environmental influences became apparent.

Quantitative genetic methods, such as studies regarding twins and adoption, were to clarify nature and nurture in order to interpret family similarity.

There are indications that, for almost all complex phenotypes, the key to the question of the origin of family resemblance is nature – things run in families mainly for genetic reasons.

Nevertheless, the valuable evidence reflecting the importance of environmental influences comes from the same quantitative genetic research, because influences merely from genes cannot explain all of the variances for complex phenotypes, and other variances have to be attributed to the environmental influences.

Non-shared environments may involve part of siblings of a family, and the rate of influence to children takes up 40% to 50%.

However, it took many decades for the full implication of these findings to be found.

If genetics can explain the similarities between siblings reared in the same family, the importance of environment lies in the fact that salient environmental stimuli can make siblings different from each other.

In other words, the environment is not shared by children growing up in the same family but is ‘non-shared’.

This meaning about non-shared environmental influences was underestimated because the field’s attention was then firmly on the nature-nurture debate.

In reality, children are not spared from environmental influences and are even more susceptible to such influences.

The term ‘non-shared environments’ is the shorthand for a component of phenotypic variance, which refers to ‘effects’ rather than ‘events’.

Several recent studies have suggested that the impact from parents can be easily interrupted by that from children of the same age.

They also show that the variation of knowledge that children gain from other cultures is increasing.

A number of interests between, whatever, fathers and mothers or parents and their children are conflicting.

Because siblings living in the same home share some of the potential genetic and environmental factors that influence their behaviours, it is difficult to tease apart whether genetic or non-genetic elements are responsible for differentiating children’s behaviours.

Sometimes, it is obvious.

Turkheimer and Waldron (2000) have noted that non-shared environmental influences may not be systematic but instead may be distinctive and in ways that cannot be ascertained.

Thus, it is challenging to work out the effectiveness of quasi-experimental behavioural genetic designs to identify systematic non-shared environmental mechanisms sectionally and longitudinally, which could motive the current study.

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Questions14 – 18

Complete the table below.

Choose NO MORE THAN THREE WORDS AND/OR A NUMBER from the passage for each answer.

Write your answers in boxes 14-18 on your answer sheet.

The Type of Impact on Children	The Range of People Involved	The Rate of Influence
14 factors from parents and family	all of the siblings	40%-50%
shared environments	15	below 16
17	part of siblings	18-50%