Argument53 【Persistence 小组】第二十六次作业

欣馨之火UID: 2183210

53. 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.


In the argument, the author draws the conclusion that increase levels of melatonin-a hormone known to affect some brain functions-before birth cause shyness during infancy and this shyness continues into later life. To support the conclusion, the author cites a study of a group of 25 infants thirteen years ago and a follow-up study earlier this year. According to the former one, the arguer concludes the shyness of infants who have been conceived in early autumn is caused by melatonin their mother produced, and according to the latter one, the conclusion that this shyness continues into later life is drawn. Close scrutiny of these studies and analysis, however, reveals that none of them lend credible support to the conclusion.

First of all, no evidence justify that the 25 infants participated in the study 30 years ago are all conceived in early autumn. If none of the infants who showed signs of mild distress when exposed to unfamiliar stimuli is conceived in early autumn, and in this case, the conceived season undoubtedly has nothing to do with the shyness of those infants. Therefore, the melatonin which naturally increases in early autumn would not be the reason of the shyness.

Secondly, even if these infants are conceived in early autumn, the author still draws hastily that the reason of the shyness of the infants is the effects of melatonin. Perhaps the infants' mothers have involved in some mental diseases which could probably influence the babies when the period of pregnancy; or perhaps these infants were treated inappositely when they came into the world in the hospital. Without take accounting to these possibilities, that increased levels of melatonin before birth cause the shyness is unsubstantiated.

Furthermore, the result of the recent study does not necessarily indicate that the shyness of these teenagers is caused by the increased levels of melatonin before their birth. The arguer does not give us any information about how these infants were adopted. As we all know, different outside environments can give different effects on ones characteristic during ones growing process. It is entirely possible that the parents of these children-now teenagers-are more likely to be shy. For that matter, it might be the characteristics of their parents, not the continuous shyness caused by melatonin, that make the teenagers to be shy now.

In sum, the conclusion in this argument relies on scant evidence and analysis which render it unconvincing as it stands. To bolster it, the author has to give more information about the time when the tested infants were conceived and the situation of the pregnant women. Moreover, I still need details about the growing process of these infants to evaluate the conclusion.