2. The following appeared as part of a letter to the editor of a scientific journal.A recent study of eighteen rhesus monkeys provides clues as to the effects of birth order on an individual's levels of stimulation. The study showed that in stimulating si

In this letter, the author believed that birth order has effects on an individual’s levels of stimulation from the study of eighteen rhesus monkeys. To support this claim, the author has cited some arguments. However, these arguments have some logical flaws and possess weak premises which will undermine the ultimate conclusion.

The study is only based on eighteen rhesus monkeys which are too small to make a clue for any scientific phenomenon to represent an entire species. There is a possibility that these selected samples might show aberrant result from normal characteristics of rhesus monkey because there is no explanation for the eating habits of samples and they might belongs to particular kind of environment shared same type of foods. These would result in the production of the high amount of cortisol in them.

The argument says that “the first-born monkeys produce up to twice as much of the hormone cortisol which primes the body for increased activity levels, as do their younger siblings”. This evidence might be true for first-born monkey or human, because any stressful situation causes production of hormone cortisol in first-born infant than their younger siblings. For example, the presence of food, feel very frightened or an attractive member of the opposite sex can be factors of increased stimulation. However, the study did not mention any increase activity or didn’t talk about the number of monkeys that exhibit this characteristic.
The argument has no explanation to believe that there exists any relationship between the characteristics of monkeys and humans.

The author claims that during the pregnancy, the first-time mother monkeys had higher levels of cortisol than did those who had had several offspring. However, he did not provide any reason for this increment of cortisol level. The situation to study the stimulation level in the monkeys refers to meeting someone “unfamiliar” while that in case of the humans is opposite when meet someone as “familiar” as their parents. These opposite situations may be but also may not be taken to have the same effect.

From the alternative explanations I have given, the argument looks very doubtable, and there are lots of things the arguer need to do to strengthen the argument.