Ar53 请多多指教O(∩_∩)O

krisoeUID: 2996451

TOPIC: ARGUMENT53 - Thirteen years ago, researchers studied a group of 25 infants who showed signs of mild distress when exposed to unfamiliar stimuli such as an unusual odor or a tape recording of an unknown voice. They discovered that these infants were more likely than other infants to have been conceived in early autumn, a time when their mothers' production of melatonin-a hormone known to affect some brain functions-would naturally increase in response to decreased daylight. In a follow-up study conducted earlier this year, more than half of these children-now teenagers-who had shown signs of distress identified themselves as shy. Clearly, increased levels of melatonin before birth cause shyness during infancy and this shyness continues into later life.
WORDS: 480
TIME: 00:30:00
DATE: 2011/1/27 16:36:00

The speaker concludes that increased levels of melatonin before birth cause shyness during infancy and this shyness continues into later life. To support the conclusion, the speaker cites a study of 25 infants who showed signs of mild distress. However, the argument suffers from several flaws which render it unconvincing as it stands.

The threshold problem is that the conclusion is base on the assumption that infants conceived in early autumn are to be influenced by increased levels of melatonin. Since the speaker provides no statistical evidence that the increase of melatonin is the determinant of the behavior of the infants conceived in early autumn, it is totally possible that it is the temperature and humidity in early autumn instead of the hormone production of their mothers that affect the infants. It is also possible that the melatonin produced by their mother will not affect their infants at all. Without ruling out these possibilities, the speaker cannot make a convincing assumption.

Even this assumption substantiated, the study of a group of 25 infants is not statistically reliable. The sample of the study should be large enough in size and be representative of all infants who showed signs of mild distress. The larger the sample size compared with the objective population, the more reliable the study. The more representative the sample is, the more valid the study. Since the author provides no statistics about the number of the total population, and proves nothing about the whether the sample is representative, the result of the study is untenable.

And even the speaker provide a valid study and substantiate the assumption that infants conceived in early autumn are influenced by the melatonin, the signs of mild distress when exposed to unfamiliar stimuli is no indication of shyness. Possibilities are there that these infants are not shy at all. Since the speaker fail to point out the correlation between the mild distress and shyness, he cannot draw the conclusion confidently.

In sum, the speaker's conclusion is unconvincing. To better assess it, I need more data about the study, including the objective population and the whether the sample is representative. Also I need the author to rule out the other factors in early autumn and provide a strong correlation between melatonin and infants’ mild distress. At last, the author should provide correlation between distress the shyness.