ARGUMENT 53 出生前melatonin的增加会导致婴儿期的羞涩并且这种羞涩将延续至生命更晚的阶段

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: 379 TIME: 00:40:00 DATE: 2011-4-9 18:00:29

In this argument, the author concludes that increased levels of melatonin before birth cause shyness during infancy and this shyness continues into later life. At first glance , this argument seems to be convincing, but further refection reveals that these evidences neither constitute a logical statement in support of its conclusion nor providing compelling support making this argument sound and invulnerable.

The threshold problem with this argument is that the author assumes that the mild distress is caused by the shyness. Although this is entirely possible, the argument lacks evidence to confirm this assumption. It is most likely that the mild distress is a reflection to the unfamiliar stimuli, that is to say, nervous does not equal to shyness. For example, even an adult may be nervous when he is exposed to an unusual odor or a tape recording of an unknown voice. Until the author provides further evidence to exclude all these concerns, it is unfounded to reach conclusion involved in the argument.

The second flaw that weakens the logic of this argument is that the author assumes that the mothers' production of melatonin leads to the mild distress of the baby. Actually , there is no evidence to prove that the production of melatonin have influence on the baby and how it works. Does it infect the mood of the mothers or the infants? The argument fails to make this point clear. In short, without better evidence ruling out these and other alternative explanations, it is reasonable to cast considerable doubt on this assumption.

The last but not the least important, even if the author can substantiate all of the foregoing assumptions, the sample of the infants is too small to prove the conclusion. The argument does not compare the group of infants to the infants born in other months, ignoring the effect of born time on the mood of the infants. It is much possible that the early autumn is a key causes that lead to the mild distress of the infants when they are exposed to unfamiliar stimuli.

To sum up, the conclusion lacks credibility because the evidence cited in the analysis does not lend strong support to what the arguer maintains. Therefore, if the author had considered the given factors discussed above, the argument would have been more through and logically acceptable.