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: 302 TIME: 0:30:00 DATE: 2006-7-12
The author concluded the causal relationship between the increased levels of melatonin before birth and shyness during infancy and later life. Such conclusion seems solid at the first glance, however, after careful consideration, there are several fetal faults that could not be ignored.
First, the study on 25 infants, one of direct evidences the author supplied, contains dozens of points that needed further consideration. All we could find from the study is these infants' unusual distress facing stimuli and the possible relationship with their mothers' increasing melatonin level. Such study contains so little infant cases that could not make any sense in statistical aspect. Furthermore, there are no detailed information about the methods and strategies that the study has taken. Perhaps, most of infants has some diseases from their parents that could also cause mild distress. In addition, the study also failed to set any control groups with similar ages and health situation who do not show the same mild distress as those 25 infants. With the control group, the study result is exactly non-cogent and unbelievable.
Second, the argument confused the possible relationship between infant mild distress and increased levels of melatonin with a causal one. In the study, the discovery has just reported the possibility between these two cases using the key word "more likely". And there is no other direct and indirect evidence showing their causal relationship. There may be some genetic disorders or diseases that cause the mild distress. There is also such possibility that the relative small infant weight and other health conditions resulting in the unusual response.
In sum, the conclusion is too hasty to be trusted. Before any final conclusion was made, the author should pay more attention to the confirmation of causal relationship between the distress and increased levels of melatonin and the like.