53 Thirteenyears 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 this argument, the arguer concludes thatincreased level of melatonin before birth leads to shyness during infancy andshyness lasts into babies' later life. To justify the conclusion, the arguercited an experiment on 25 babies showing more or less signs of distress whenexposed in strange circumstances and claims that this distress is related totheir mothers' increased melatonin. And a follow-up study on these babies showsthat the shyness still exists in their later life. I find this argument flawedin several respects.
Firstly, the sample of the mentioned studyis too limited not only because of the mere 25 babies but also some otherproblems.
The most important thing is that the arguersimply equates mild distress with shyness. After all, it's quite common forinfant to show distress because little babies are always scared ofanything.
The arguer doesn't inform usabout the exactly number of babies conceived in autumn. I believe that it'sbetter separate the babies into two groups and make a comparison betweeninfants who are conceived in autumn and those who are not. Without controllingthe sample of the experiment, I don't feel this research any persuasive.
Secondly, the arguer failed to establish adirect causal connection between the mothers' increased level of Melatonin andshyness of their infants. There is no scientific evident given to explain howMelatonin causes shyness. Even if such explanation makes sense, the high levelof Melatonin of the mothers is not necessarily going to be inherited by theiroffspring. The arguer gives us a vague correlation between mothers' Melatoninand children's shyness, so it's also fair to guess that the Melatonin shouldonly influence the mothers but does nothing to the infants.
Thirdly, even we accept the causal relationbetween Melatonin and infants' shyness, the arguer hastily asserts that theshyness continues into later life. There is possibility that children confesstheir shyness to you while they aren't really timid person because differentindividuals may define the term shy in various ways. What's more, the pudencycharacteristic of a teenager is not consequentially caused by the Melatonin.For instance, the growth atmosphere of a child does play a crucial role indeveloping the child's characteristic; some special event ever happened duringthe childhood changes the characteristic a lot. The arguer cannot ascribe theteenagers' shyness to the early Melatonin of their mothers without eliminatingsuch factors as mentioned above.
In sum, the argument is logically unsound.To strengthen it the arguer must show that the babies in the experiment dobehave their shyness, and that the mothers' Melatonin is one of the factorsthat lead to their babies' inherent personality of pudency. To better assessthe argument, I would like the arguer not to neglect some other causations ofthe shyness developed during the children's childhood.