Argument53

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.
(456 words)
In this argument, the author comes to the conclusion that increased levels of melatonin before birth cause shyness during infancy and this shyness coutinues into later life. To justify this conclusion, the author cites a study about a group of 25 infants and a follow-up study with these children-now teenagers earlier this year. This conclusion seems to be logical, however, deep scrutiny shows several mistakes in it which I will discuss them below.
Firstly, the studied conducted by some researchers thirteen years ago is statistically unreliable. The researchers just studied 25 infants, which make me suspect that thay can' t represent the general infants. It is highly possible that these 25 infants are special, and the reason why those researchers collected these infants rather than others was to get a result which they want to see. If this is the case, I can't be pursuaded that any data deriving from this study can be used to conclude any sound results.
Secondly, even if these infants are representative, the author can't convince me that this high rate of shyness has anything to do with melation, let alone that the former one has been caused by the later. Maybe the melatonin didn't take any function to effect the shyness, or the melation did something to the mother, not the infants, or maybe the melatonin effected these infants, but just in autumn. Without ruling out these or other possible reasons, any conclusion standing on this assumption are not convincing.
Finally, even if increased levels of melatonin before birth cause shyness during infancy, it doesn't mean that it can also cause this shyness continue into later life. To begin with, the author didn't show any data about those infants who wasn't as shy as these infants in the study, so we didn't know whether the rate of shyness among these infants is high or not. Even if the rate of shyness is higher in these children who was more shy than others during infancy, maybe there are other factors effecting this rate. As we all know that, the family atmosphere, and teaching of the teachers, the enviorment of the surrounding during his or her youths life can do something good or bad to effect or even deciede whether a child is shy when he grow up. Without explaining these or other possible factors, the author can't convince me that the melatonin before birth has anything to do with the shyness in later life.
In sum, in order to support thr conclusion, the author must prove that the infants in the study are representative. He also has to make sure that it is the melatonin effected the extra shyness during infancy and in later life other than ant other possible phenomenon.