Shenk states in Chapter 2 that intelligence is a process,
not a thing that is inherited on the basis of genetics. Analyze the early
environmental triggers proposed in Chapter 2 (pages 47-48) that make
intelligence a process that, while initiated at an early age, contribute
significantly to the GxE model. In explanation of each trigger’s relationship
to the GxE model, be sure to analyze how these environmental triggers influence
the expression of genes, using evidence presented for each factor along with
Shenk’s relationship between genes, proteins, the environment, cells, and traits
(page 31). In addition, relate these early environmental triggers to the biological
concept of imprinting, as elaborated on in Section 51.2 of Campbell. Analyze
how each trigger presented by Shenk serves as an imprinting stimulus that
causes an alteration (genetically and behaviorally) during the sensitive period.
Nick Sotos (nsotos13@gmail.com)
Nick Sotos (nsotos13@gmail.com)
Hart and Risley studied the development of children, comparing children who came from professional homes, working homes, and welfare homes. All in all, they found that children who came from professional homes were generally more intelligent, while children who came from welfare homes were generally less intelligent (46). This disparity is rooted within interactions between the child and the environment. The environment provides certain stimuli, and when the children encounter these stimuli, they react accordingly and it affects them for the rest of their lives.
ReplyDeleteThe first stimuli, or trigger, is “speaking to children early and often” (47). Hart and Risley noted a large disparity in the number of words spoken in each type of household, as well as quality of the words. Children are most impressionable when they’re young. Their infantile years are their sensitive periods, and the children are constantly imprinting (Campbell 1126). The University of North Carolina actually undertook a project to determine the effect of environmental enrichment to children from birth, naming it the Abecedarian Project (47). The goal was to “enhance children’s school readiness, to ease their transition into elementary school, and to investigate the short- and long-term effects of providing high-risk children with educational experiences early in life. Care was provided five days a week, and focused on developing the cognitive, social, language, and gross motor skills of the children through age five” (http://www.childtrends.org/Lifecourse/programs/CarolinaAbecedarianProgram.htm). By continuously talking to the children, this provided them a lot of stimulus. The human brain is constantly working, and the childrens’ brains are forced to work harder to meet the challenge. The genes and environment are working together. However, since the children are developing, the environment has more bearing than genes. The children who were raised in a professional home became more intelligent because they were given more opportunities, more encouragement, and more attention. Even if the welfare or professional children were predisposed to do something particularly well, or predisposed to not to certain things well, the fact that they were raised with a certain set of stimuli guaranteed that environment would have almost all of the impact on a child’s development. Children will pick up on the frequency of speech as well attempt to follow the complexity of speech, because infants learn extremely quickly. They are stimulated into thinking harder and developing mental skills that will stay with them as they get older.
The second trigger is “reading early and often” (47). This is another case where environment has a much bigger impact than genes. Of course, genes may help determine which children have an easier time learning to read. However, reading ability is increased by actually reading. Children who read more will become more intelligent because the children are forced to think more and open their minds (http://ezinearticles.com/?4-Top-Reasons-to-Introduce-Reading-at-an-Early-Stage&id=5056381). Children are like sponges; they are very impressionable and learn things quickly. By reading early and often, not only is the parent helping the child develop thinking skills, the parent is also fostering a good habit. The more parents read to children, the faster the children will begin reading on their own. By teaching the child to read during the sensitive period, the child can develop a habit of reading or doing other such constructive activities. Reading brings a behavioral alteration for the better. Also, as the child grows up and continues to read, he or she will then read early and often to his or her children, continuing a cycle.
PART ONE
Annie Lee (xxannie.leexx@yahoo.com)
The next trigger is nurturance and encouragement. Within the study, Hart and Risley discovered that children from professional households received much more encouragement than the children from welfare households. Encouraging children gives them a sense of importance, of accomplishment. Many children strive for the approval of their parents, so many times, they will continue to do things that merit the encouragement of the child. If no encouragement or nurture is given at all, and the child is constantly corrected and discouraged, then the child will usually end up with an inferiority complex, thinking that they are never quite good enough. The child will continue to work towards more encouragement. Like reading, the children will soak up the encouragement and take these encouraging comments as a sign to continue excelling. This trigger will help in altering behavior, but not really genetics. This is mostly a case of epigenetics, because the home environment will really have much effect on the “giant control board” (Shenk 19).
DeleteAnother trigger is setting high expectations. Sherman and Key found that “children develop only as the environment demands development.” (47) Encouragement really helps children want to start and do things. By setting expectations, children are encouraged to reach, try something that is harder than usual. The children will constantly be trying to do better and challenge limitations. Our brain plasticity guarantees that our brain has “capacity to become, over time, what we demand of it” (36). The more is demanded of a child, the harder the brain will work. This will increase mental capacity, as well as foster a feeling of hard work and perseverance. Then the children, once they grow up, will continue setting high expectations for themselves, testing limits and challenging themselves. High expectations also cause an alteration in behavior, due to epigenetics. Setting high expectations and meeting them is a choice made by each individual.
The next trigger is embracing failure. This goes along with the previous trigger, the trigger of setting high expectations. By setting lofty goals, one must also expect failure. Children are encouraged to push their limits and reach their potential. However, sometimes, it’s too much. In this way, failure must be embraced and not seen as something shameful or wrong. By expecting too much of the child and not accepting anything but complete success polarizes a child. They can either strive to be perfect, becoming too competitive, or they can give up as a whole, because they feel like they cannot beat others. By embracing failure, parents are showing that what’s important is that each child tried his or her best. This causes alteration behaviorally but is also rooted in genetics. Of course, behavior will be altered for the future, because by embracing failure, the individual is creating shades of gray, instead of just having black and white, success and failure. However, the parents may know that their child is genetically predisposed to be good at or not good at something; thus, it may not create an alteration but failure should also take into consideration the pre-existing abilities of the child.
Finally, the last stimulus is believing in growth. Basically, this is the belief that a person can hone their abilities. Mental fortitude is crucial in development of an individual. By believing that they can become better, children will become better because they want to. If we are stuck believing that genes are the sole factors controlling our lives, then nobody would ever try or challenge themselves, because they don’t believe that they can actually do it. If every organism didn’t try because they thought they couldn’t do it, then evolution would grind to a halt. Evolution and adaptation stem from the effort and belief that there is room for growth. Like most of the other stimuli, alteration is brought behaviorally.
PART TWO
Annie Lee (xxannie.leexx@yahoo.com)
PART 1/2
ReplyDeleteA conscious parent who speaks to the child often and early (to the extent of a fetus) is exemplifying one of the many positive environment triggers David Shenk listed that will stimulate the child (47). The role of the parent is incredibly important—they provide the environment the child’s genes will interact with. Gene expression and the proteins that correlate are ultimately products of both environmental and genetic influence.
David Shenk gives us a new model of genetic development, calling it GxE: genes, proteins, and environment signals constantly interact with one another—as opposed to the old view which environment only influences cell function (31). In the parent-offspring communication example where parents widen their eyes and speak in an exaggerated high pitch, the infant’s brain becomes stimulated and more attentive. The frontal lobe is activated; the volume of connections in the frontal lobe is directly correlated with the development of emotional regulation (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2675477/). When an infant is constantly stimulating the frontal lobe, there is high activity at synapses (a region where nerve impulses are transmitted and received). Due to repeated stimulations, signaling increases and the activity of one synapse correlates with that of other synapses—the connection is strengthened (Campbell 1079). And how is synapse activity increased? The genes in charge of synapse formation must have been expressed—as a result of the stimulus provided by the environment. By increasing neural connections in the frontal lobe, emotional maturity grows.
A scenario of the parent-offspring communication example that fits within David Shenk’s model of GxE could the following: the environment (parent talking with infant) influences cell-specific gene expression to produce a cell called glia which secretes proteins that promote synapse formation (http://med.stanford.edu/news_releases/2005/february/glia.htm). Thus, if cells like glia continue to secrete synapse—promoting proteins, neural connections in the frontal lobe—also known as the emotional control center –continue to be strengthened and emotional regulation to develop. As a result, a trait may (or may not) develop in a child that is emotionally precocious.
This example of parent—offspring communication can also be related to the idea of imprinting. Imprinting is the formation of a long-lasting behavioral response to a particular identical or object during a sensitive period (Campbell 1126). Humans also exhibit imprinting to some extent. Before birth, the fetus experiences a period similar to the sensitive period in development—there’s learning, protein making, organ development, etc. DNA methylation, a gene repression mechanism, was even turned off (http://neurosciencenews.com/environment-gene-regulator-brain-executive-hub-dna-methylation/). It is during this time that fetuses can learn to recognize their mother’s voice if their mother speaks to them. This fact is well-documented since studies have shown that the fetal heart rate increases in response to the voice of the mother as opposed to a stranger (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2675477/). In addition, like I mentioned before, the fetus could also enhance its ability for emotional regulation.
Linda Xu (lindaxu22@hotmail.com)
PART 2/2
ReplyDeleteThis topic relates to the theme of change and continuity. It relates to “change” since the stimulus caused gene expression to change and result in cell differentiation (glia). Glia then produced proteins that stimulated synapse formation in the frontal lobe. It also relates to “continuity” because once the stimulus is gone, stimulated synapse formation will stall. Without the stimulus, negative feedback might ensue. Or, methyl groups can be added to histone tails of the chromatin and promote condensation, inhibiting gene expression (Campbell 358).
While I agree with the basis of Annie’s post, my response differs in that I focused on one positive environment trigger—“speaking to children early and often”. By focusing on one stimulus, I went into very specific research about how exactly the stimulus is affecting gene expression. I took different pieces of research to try to fit it together under David Shenk’s GxE model. I think a very important part of this understanding is the neurological aspect of it. I wanted to understand how this stimulus was affecting the brain. However, I understand Annie’s sociological viewpoints. But, I disagree with some generalizations she made. For example, Annie wrote, “Since the children are developing, the environment has more bearing than genes.” From my interpretation, there is no factor that can be attributed more to the development of children. David Shenk’s model is the interaction of environment and genes: one can’t exist without the other. There are people who try extremely hard but do not improve significantly. To those, David Shenk replies it’s because, “genes are [also] involved… ‘When individuals deliberately push themselves beyond the zone of relative comfort…, they [induce] an abnormal state for cells …[which] will trigger the activation [of] dormant genes’” (69). Thus, genes are as much as a part of development as the environment. If the environment does not interact with genes to induce gene expression, there is not going to be significant improvement.
Linda Xu (lindaxu22@hotmail.com)