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Introduction:
Environment and
heredity have been considered two key factors that influence learning. Learning
environment is critical in sound teaching and learning process. Review of
literature shows that Internal and external environment affect learning to a
greater extent. Besides environment, heredity/genetic factor has also been
found to have some influence on human behavior. This article briefly discusses
these factors and their influence on learning.
Childhood learning and literacy in
general is dependent upon both prerequisites in the individual and the
environment where this individual is growing up. Individual variations in the
acquisition of literacy can of course depend upon cognitive and verbal ability
as well as specific language difficulties such as articulatory and perceptual
phonetic factors. In addition to this home environment plays a decisive role in
the development of linguistic competence. In a home where the parents read for
the child and where children’s questions are encouraged and responded to in an
elaborated way the chances for a successful reading and writing competence are
much better than in a linguistically deprived environment. Genetic factors also
are influential since parents with reading and writing problems often get
children with the same type of difficulties. Naturally it also works the other
way around so that parents who are excellent readers and writers both
genetically transfer this and show their children all the joys of being part of
the world of letters and books. Also in intellectually proficient families
there are children at risk of developing reading and writing difficulties. The
parents could be too occupied to notice the need of stimulation in their child.
Resources of the school might be insufficient in areas where most of the
children are expected to read and write without problems, and the child might
feel different and stupid in comparison to the classmates. In addition to this
there are substantial differences in physical maturation between boys and girls
contributing to the boys having more difficulties in young ages to adapt to the
traditional school system. This might increase the number of boys being
referred to special education.
·
Influence
of Environment on Learning
The behavior and
development of people is mostly affected by the physical environment in which
the live. School environment is vital in enhancing learning. A conducive
environment of the school compound for instance, helps learners to be able to
achieve well in their academic pursuits. The school environment can be viewed
as the personality of the school which makes it distinct and unique from
others.
A survey by Swedish
Work Environment Authority (2005) investigated the environmental impact on
effective instruction. The study found out that a good psycho-social school
environment is an important prerequisite of learning and of pupil satisfaction
in school. The study dealt specifically with environment and its impact on
effective learning without looking into the overall components of effective
learning.
The physical
environment of the classroom also affects the individual children and the group
as a whole. The physical environment includes the size of the room, the colors
of the walls, the type of flooring, the amount of light, and the number of
windows. A physical environment which is secure, appealing and well planned
helps children to effectively engage in healthy learning activities. Such an
environment can support goals for children and helps them to interact in
positive ways, thus reinforcing learning.
If genetic influences account for
between 40 and 80 percent of the variation in intelligence, then environmental
influences account for between 20 and 60 percent of the total variation.
Environmental factors comprise all the stimuli a person encounters from
conception to death, including food, cultural information, education, and
social experiences. Although it is known that environmental factors can be potent
forces in shaping intelligence, it is not understood exactly how they
contribute to intelligence. In fact, scientists have identified few specific
environmental variables that have direct, unambiguous effects on intelligence.
Many environmental variables have small effects and differ in their effect on
each person, making them difficult to identify.
Schooling is an important factor that
affects intelligence. Children who do not attend school or who attend
intermittently score more poorly on IQ tests than those who attend regularly,
and children who move from low-quality schools to high-quality schools tend to
show improvements in IQ. Besides transmitting information to students directly,
schools teach problem solving, abstract thinking, and how to sustain
attention—all skills required on IQ tests.
Many researchers have investigated
whether early intervention programs can prevent the lowered intelligence that
may result from poverty or other disadvantaged environments. In the United
States, Head Start is a federally funded preschool program for children from
families whose income is below the poverty level. Head Start and similar
programs in other countries attempt to provide children with activities that
might enhance cognitive development, including reading books, learning the
alphabet and the numbers, learning the names of colors, drawing, and other
activities. These programs often have large initial effects on IQ scores.
Children who participate gain as much as 15 IQ points compared to control
groups of similar children not in the program. Unfortunately, these gains seem
to last only as long as the intervention lasts. When children from these
programs enter school, their IQ declines to the level of control groups over a
period of several years. This has come to be known as the “fade-out” effect.
Even though early intervention
preschool programs do not seem to produce lasting IQ gains, some studies
suggest they may have other positive long-term effects. For example, the
Consortium for Longitudinal Studies reported that participants are less likely
to repeat grades, less likely be placed in remedial classes, and more likely to
finish high school than comparable non-participants—even though both groups
show about the same levels of academic achievement. Preschoolers in early
intervention programs may also benefit from improved health and nutrition, and
their mothers may sometimes benefit from additional education that the programs
provide. Because a substantial portion of the variation in intelligence is due
to environmental factors, early intervention programs should be able to produce
significant and lasting IQ gains once the specific environmental variables that
influence IQ have been identified. Researchers continue to search for the
interventions that will increase IQ and, ultimately, academic achievement.
·
Influence
of Heredity on Learning
Many aspects of
human characteristics such as height and eye color are largely determined by
genetics. Learning has also been tied with genetic influence.
In the 17th and 18th centuries, philosophers such as René
Descartes and Immanuel Kant argued that human cognition was largely reflective
of genetically determined predispositions. They maintained that humans are born
with certain cognitive inclinations. On the contrary, John Locke compared the
human mind to a piece of blank paper without any ideas written on it (tabula
rasa), meaning blank slate. He suggested that only from experience do
humans draw reason and knowledge. Following these opposed ideas, scholars have
continued to explore the influence of heredity on learning.
A study by Frank et
al (2007) on how genes influence learning is a source of new insights among
scientist on the role of genetics in learning. The study found links to
learning behaviors in three separate genes associated with dopamine (a chemical
in the brain that is associated with pleasure, learning among other behaviors).
The study found genetic differences between slow and fast learners. Such
findings among others, have continued to address the issue of genetic influence
on learning.
In behavioral genetics, the heritability
of a trait refers to the proportion of the trait’s variation within a
population that is attributable to genetics. The heritability of intelligence
is usually defined as the proportion of the variation in IQ scores that is
linked to genetic factors. To estimate the heritability of intelligence,
scientists compare the IQs of individuals who have differing degrees of genetic
relationship. Scientists have conducted hundreds of studies, involving tens of
thousands of participants that have sought to measure the heritability of
intelligence. The generally accepted conclusion from these studies is that
genetic factors account for 40 to 80 percent of the variability in intelligence
test scores, with most experts settling on a figure of approximately 50
percent. But heritability estimates apply only to populations and not to
individuals. Therefore, one can never say what percentage of a specific
individual’s intelligence is inherited based on group heritability’s alone.
Although any degree of genetic
relationship can and has been studied, studies of twins are particularly
informative. Identical twins develop from one egg and are genetically identical
to each other. Fraternal twins develop from separate eggs and, like ordinary
siblings, have only about half of their genes in common. Comparisons between
identical and fraternal twins can be very useful in determining heritability.
Scientists have found that the IQ scores of identical twins raised together are
remarkably similar to each other, while those of fraternal twins are less
similar to each other. This finding suggests a genetic influence in
intelligence. Interestingly, fraternal twins’ IQ scores are more similar to
each other than those of ordinary siblings, a finding that suggests
environmental effects. Some researchers account for the difference by noting
that fraternal twins are probably treated more alike than ordinary siblings
because they are the same age.
Some of the strongest evidence for
genetic influences in intelligence comes from studies of identical twins
adopted into different homes early in life and thus raised in different
environments. Identical twins are genetically identical, so any differences in
their IQ scores must be due entirely too environmental differences and any
similarities must be due to genetics. Results from these studies indicate that
the IQ scores of identical twins raised apart are highly similar—nearly as
similar as those of identical twins raised together. For adoption studies to be
valid, placement of twin pairs must be random. If brighter twin pairs are
selectively placed in the homes of adoptive parents with higher intelligence,
it becomes impossible to separate genetic and environmental influences.
Another way of studying the genetic
contribution to intelligence is through adoption studies, in which researchers
compare adopted children to their biological and adoptive families. Adopted
children have no genetic relationship to their adoptive parents or to their
adoptive parents’ biological children. Thus, any similarity in IQ between the
adopted children and their adoptive parents or the parents’ biological children
must be due to the similarity of the environment they all live in, and not to
genetics.
There are two interesting findings
from studies of adopted children. First, the IQs of adopted children have only
a small relationship to the IQs of their adoptive parents and the parents’
biological children. Second, after the adopted child leaves home, this small
relationship becomes smaller. In general, the IQs of adopted children are
always more similar to their biological parents’ IQs than to their adoptive
parents’ IQs. Further, once they leave the influence of their adoptive home,
they become even more similar to their biological parents. Both of these
findings suggest the importance of hereditary factors in intelligence.
People sometimes assume that if
intelligence is highly heritable, then it cannot be changed or improved through
environmental factors. This assumption is incorrect. For example, height has
very high heritability, yet average heights have increased in the 20th century
among the populations of many industrialized nations, most likely because of
improved nutrition and health care. Similarly, performance on IQ tests has
increased with each generation, yet few scientists attribute this phenomenon to
genetic changes. Thus, many experts believe that improved environments can, to
some degree, increase a person’s intelligence.
Some genetic disorders, such as
phenylketonuria (PKU) and Down syndrome, may result in mental retardation and
low IQ. But evidence for genetic influences should not be interpreted as
evidence of a direct connection between genes and intelligence. In PKU, for
example, a rare combination of recessive genes sets the stage for a series of
biochemical interactions that ultimately results in low IQ. These interactions
only occur, however, in the presence of the amino acid phenylalanine. If the
disorder is detected early and phenylalanine is withheld from the infant’s
diet, then large IQ deficits do not develop.
·
How Does Heredity and Environment Influence on learning and
intelligence?
There are many claims, opinions, and
arguments about where intelligence comes from - is it from our genetic
heritage, or is it a consequence of the environment and our experiences? Below
are some research findings and compelling arguments about how our genes and our
society influence intelligence.
·
Genetic Influences on learning and Intelligence
Research findings confirming that
intelligence is a by-product of our heredity revolves around finding specific
genetic markers and associating IQ levels of parents and siblings.
Genetic markers on intelligence are
believed to be found in chromosomes 4, 6 and 22. The genetic marker in
chromosome 6 appears in 1/3 of children with high IQ, and only 1/6 of children
with average IQs.
·
Environmental Influences on learning & Intelligence
Environmental influences come in
different packages - family, ethnicity, socio-economic status, gender, and
education.
The family has a critical role in
elevating IQ scores. Communication received during the first 3 years of life is
the primary predictor of Stanford-Binet IQ score at age 3. Moreover, simply
moving or exposing children to families with better environments increases
their IQs by 12 points.
The notion of intelligence also
differs across cultures. Socio-economic status is also very important. Having
the means and the resources gives a sense of security and access to stimulating
environments.
One's gender can also influence
intelligence. On average, males and females have similar IQ levels. However,
males' scores are more variable. Males specifically perform better in spatial
and abstract reasoning, while females tend to be better at finding synonyms.
Lastly, and perhaps the most
important of all, is education. Intervention day care increases IQ score by 17
points at age 3, and 5 points by age 15. South African Indian children lost 5
IQ points per year of schooling delayed due to the unavailability of teachers.
The gap between African and White Americans on standardized test scores is
narrowing, especially in college, most likely because of having similar
educational environments. In 1999, James Flynn also discovered that the human race
is becoming more and more intelligent (also called the Flynn Effect). In the
ancient times, only adult priests can read; nowadays, 7-year old children must
already know how to read.
·
Variation in early language and literacy development
Children acquire language proficiency
in communication with the environment. Language development is thus linked to
both a cognitive and a socio-cultural perspective. Language learning is an
adaptive process consisting of biological prerequisites to process information as
well as the communication patterns and language structures that the child
encounters. The child stores information and adapts to new stimuli by
reorganizing and adapting. This is however a reciprocal process since the
social environment also adapts to the child. When the child begins to talk, the
child possesses a powerful tool that can be used in influencing the social
environment. Speech starts with an increase in vocabulary which is followed by
morphology and grammar in typically developing children. This process is
dependent upon the social environment of the child but does not require
specific training. Literacy on the other hand does not occur by itself but has
to be taught in an educational process. It is therefore not self-evident that
children who are orally advanced are not encountering difficulties in learning
to read and write. On the other hand children who are orally advanced can show
profound difficulties learning to read.
The variation in language development
is therefore dependent upon perceptual, motor and cognitive abilities relevant
for language learning but also on the interplay between the child and its
social and educational environment.
·
Conclusion:
Today
researchers agree that heredity and environment have an interactive influence on
intelligence. Heredity places an upper and lower limit on the IQ that can be
attained by a given person. The environment determines where within these
limits the person’s IQ will lie. If
the environmental factors were more important than
the genetic factors the defense would have been very high. Adoption studies
also show that adopted children somewhat resemble their biological parents in
intelligence researchers have found that IQ scores of adopted children more
highly correlation with that of their biological parents than that of their
adaptive parent’s IQ.
Because of strong genetic link
between the adopted children and their biological parents it can be concluded
that heredity is more important than environment. Researchers have
also found that heritability of intelligence increases from
as low as 0.45, in infancy to as high as 0.80 in late adulthood. This is
because as we grow older, the effect of environment reduces upon us and we
interact more with the environment as we like not under our parent’s pressure or
the of society.
Example: Sometimes parents push children to
become engineers / doctors, incompatible environments, but as adults these
individuals may select their own career environments.
The heritability index has several
flaws as it greatly depends on the data fed into its calculation. The data is
collected from traditional IQ tests which is deemed by some experts as not the best indicator
of intelligence. Also heritability assumes that both environment and heredity
are separate factors and each excerpts a distinct amount of influence but genes
and environment works together, with the environment shaping the genetic
activity. Children are not predestined to have an intelligence level similar to
their biological parents.
Example: Most children of extra ordinary
intelligence were born to average intelligence parents. Genetic ancestry of a
child is not a 100 % or surefire predictor of his / her intelligence
environment also makes an appreciable difference as we shall now see.
Today most researchers agree that
modifications in environment can change the IQ scores of individuals
considerably. Biological unrelated children raised together in the same home
have some similarity in IQ. A correlation of 0.25 exists for unrelated children
reared together in the same environment moreover, blacks who are raised in
economically enriched environments have IQ score similar to whites in
comparable environments.
Example: in a study of black children adopted
by middle class while families at an early, the IQ of the adopted children
average 15 point above the IQ scores of un-adopted black children the racial
gap in IQ narrows considerably after college education.
Early childhood literacy development
is dependent upon both hereditary and other individual prerequisites as well as
influences in the home, peer group, school and society. An interactional model
based on results from twin research illustrates the importance of restrictive
and stimulating factors in the environment at various levels. A permissive
setting tends to increase the literacy variation depending upon heredity and
home background influences.
From the research regarding
heredity-environment influences on early childhood literacy it can be concluded
that genetic aspects are evident and particularly so for children at risk for
developing reading and writing difficulties. Phonological awareness seems to be
a key factor in this respect. Children who have difficulties combining sounds
and letters need structured and encouraging reading instruction by preschool in
order to protect them from school failure later on. Parents are both
transferring their genes to their children and a home environment where reading
and writing might be more or less encouraged.
*****
Tags
B.Ed