Shenk states, "The worst kind of blame, and the most common, is on one's own biology. This is the great final irony of genetic determinism: the very belief of possessing inferior genes is perhaps our greatest obstacle to success" (123). He goes on to say, "there is no age of impossibility" (124). If in the same environment, according to Shenk and according to other theories, can a twenty-year-old and a fifty-year-old achieve the same greatness? Can the timing of gene activation still have an effect on the ability of a person as he or she ages?
Jenna Sherman (jsherm013@aol.com)
In theory, a 22 year old and a 50 year old can achieve the same level of greatness if put under the same conditions; however, the reason we do not see such equal abilities in today's society is not genetics, but the environment that each is in. As Shenk states, "with every year, you have less time, less scheduled flexibility, less energy and less brain and muscle plasticity" (124). As a result, the common response to such a question would be to doubt the older generation and simply believe that age determines ability. This same mindset can be seen in nature in the optimal foraging model in which "natural selection should favor a foraging behavior that minimizes the costs of foraging and maximizes the benefits" (Campbell 1133). If an animal is older and slower, then they will not survive because they will not be able to compete with the younger animals and predators. However, in terms of human capabilities, this ideal does not hold true. The reason why an older person normally does not achieve the same greatness as a younger person is because an "unmarried twenty year old [can] practice deliberately and intensively for hours every day" (Shenk 124) whereas a "married forty-five-year old with to young kids and a jumbo mortgage" (Shenk 124) has no time to practice. As a result, the younger generation usually has more time to build up muscle memory and skills whereas the older generation loses precious time in which they could be practicing. In theory, if one practices, age would not affect gene activation and a person would have the same abilities as another no matter what their age. With practice, "when individuals deliberately push themselves beyond the zone of relative comfort and engage in strenuous physical activity" (Shenk 69), then this will trigger the expression of dormant genes within DNA. This holds true no matter what one's age. Take Brett Favre, an NFL quarterback. Brett played "297 consecutive games" (http://www.aolnews.com/2010/12/15/peyton-manning-pauses-to-reflect-on-brett-favres-amazing-and-i/) up until the age of 40. He played at a level higher than almost any other NFL player who's average age was mid 20's. Favre is living proof that in the same environment, an older person can perform at the same level as a younger person. The reason that Brett is able to do so is because he is given the time and opportunity to practice just as much if not more than a younger person. "Older people should perform the activities they enjoy as the highest success rates in lifestyle change are achieved by those who choose enjoyable activities that can be incorporated into daily routines" (http://www.bgs.org.uk/index.php?option=com_content&view=article&id=1116:bpgphysicalactivity&catid=12:goodpractice&Itemid=106). Now, more often than not, an older person must practice more than a younger person to be on the same level as that person because of deteriorated muscle mass and health levels that may not be on par with that of a younger person. The heart, the muscle that pumps blood throughout the body, deteriorates as time goes on. The heart muscle eventually wears out, be it a myocardial infarction that leaves some of the muscle inactive, or just time and use. Similarly, the chance of plaque formation in arteries is much higher in older subjects. As a result, excursive is often much more difficult in older patients. But, in theory, if they excursive regularly and often and regain their strength, then they can perform at a level equal to or higher than a younger subject in the same conditions.
ReplyDeleteAs people get older, their gene expression changes and causes them to physically age, regardless of their environment. Interactions with the environment can have effects on the rate at which aging proceeds (for example, smoking accelerates aging while regular exercise decelerates the physical effects of aging), but people eventually age no matter what environment they're in. For this reason, I disagree with Sai that the main reason that a twenty-year-old would be more likely to achieve more than a fifty-year-old is influences of the social and cultural environment. If a twenty-year-old and a fifty-year-old were in the same environment, the twenty-year-old would be more likely to achieve greatness than the fifty-year-old because the fifty-year-old's aging would cause physical changes in the brain that make learning more difficult. As Sai writes, however, this does not mean that a fifty-year-old could never achieve the same greatness as a twenty-year-old; a fifty-year-old would simply have to work harder and practice more to achieve the same goal.
ReplyDeleteOne of the major ways that people achieve greatness is by learning. People learn by strengthening preexisting connections or making new connections in the brain. These abilities are part of neural plasticity. Neural plasticity is the capability of the nervous system to change its structure in response to its own activity (Campbell 1079). As people get older, however, their neural plasticity decreases and their connections can weaken or even be lost. In one experiment, scientists studied how young, middle aged, and old rats' brains responded and recovered from stress. One of the observed effects of stress was the shortening of dendrites in neurons. Dendrites are branches that stick out of the cell body of the neuron and receive signals from other neurons (Campbell 148). Shortened dendrites would break and weaken connections in the brain and limit neurons' ability to form new connections. The dendrites of the young rats recovered after a short while, but the dendrites of the older rats did not. The scientists conducting the experiment concluded “that with aging you lose a lot of the capacity to have experience-induced plasticity” (http://www.msnbc.msn.com/id/43159632/ns/health-aging/t/stress-cuts-aging-brains-ability-learn-new-tricks/#.T4jDqO3TJSU). For this reason, a fifty year old would not be able to learn and develop greatness as well as a twenty year old would because the fifty year old would have decreased plasticity and be less able to make new connections or strengthen connections in his or her brain when compared to the twenty-year-old.
Another advantage that a twenty-year-old would have over a fifty-year-old is sleep. Studies have shown that “sleep and dreams are involved in consolidating learning and memory” (Campbell 1071). Without sleep, people can't process or maintain short term memories and synapses that were made earlier in the day. A study from last November found that older people don't process short term memories effectively even when they do sleep. In the study, people from 18-30 and 50-80 years old memorized a sequence of colored doors to travel through virtual rooms and 12 hours later tried to reproduce what they'd memorized. The young group improved by 50% after sleep compared with not sleeping, but the older group's results were the same after sleeping and after staying up. The scientists this that this is probably because the average sleep cycle for old people is shorter than the average sleep cycle for young people. Because their sleep cycle is shorter, “older people spend less time in sleep stage 2, in which the day’s events are played back and committed to memory”(http://www.sciencenews.org/view/generic/id/336077/title/Sleep_doesnt_help_old_folks_remember).
Adele Padgett adele.padgett@gmail.com
This would cause a fifty-year-old to be able to retain less learning overnight than a twenty-year-old, making it easier for the twenty year old to “achieve greatness” by maintaing the strength and number of new connections made from practice earlier that day. The hormone that plays the main role in regulating the sleep cycle is melatonin. Melatonin production is increased during the night and decreased during the day. Melatonin induces sleep by lowing body temperature and causing drowsiness. As people age, they produce less melatonin, and less melatonin could possibly lead to shorter and more disrupted sleep cycles (http://onlinelibrary.wiley.com/doi/10.1111/j.1600-079X.1986.tb00760.x/abstract). Producing less melatonin leads to quicker sleep cycles and does not allow older people to process information learned during the day. Although scientists are not sure why people produce less melatonin as they age, one change in gene expression that could lead to less melatonin is the production of less of one of the enzymes that converts serotonin to melatonin, arylalkylamine N-acetyltransferase (AANAT). Because “AANAT plays a unique time-keeping role as the molecular interface between the environment and the hormonal signal of time, melatonin” a decrease in expression of the gene that codes for AANAT could lead to less conversion of serotonin to melatonin, and consequently, less melatonin could lead to changes in the sleep cycle (http://www.springerlink.com/content/4mkvabxfvlnnkp6p/).
ReplyDeleteDifferences in achievement of a twenty-year-old and a fifty-year-old in the same environment relate to the theme of structure and function because the differences between an average twenty-year-old and an average fifty-year-old are physical differences. Older people tend to have less neural plasticity, meaning that their neurons aren't as able to make new connections and strengthen old ones as the neurons of a young person. This structural difference translates to the functional difference that young person has a much higher ability to learn new things than an old person. During sleep, new connections or strengthened connections from the day are reinforced during stage 2 of the sleep cycle. However, the sleep cycle in older people is shorter, so their brains aren't able to reinforce or process as many of the learning connections as young people.
Adele Padgett adele.padgett@gmail.com