「Question No. 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 situations (such as an encounter with an unfamiliar monkey), firstborn infant monkeys produce up to twice as much of the hormone cortisol, which primes the body for increased activity levels, as do their younger siblings. Firstborn humans also produce relatively high levels of cortisol in stimulating situations (such as the return of a parent after an absence). The study also found that during pregnancy, first-time mother monkeys had higher levels of cortisol than did those who had had several offspring."

　　Write a response in which you discuss one or more alternative explanations that could rival the proposed explanation and explain how your explanation(s) can plausibly account for the facts presented in the argument.

　　Introduction

　　The author’s assertion about the effects of birth order on an individual's levels of stimulation is untenable / questionable / dubious. As a matter of fact, there are a number of alternative explanations that can also account for the monkeys’ or humans’ high levels of production of hormone cortisol.

　　Body

　　Alternative explanation 1: (常见逻辑疑点：偷换概念：出生顺序和年龄大小不是一个概念)

　　Instead of birth order, the age of the monkey may be the reason behind the secretion of hormone cortisol. In other words, when the second-born monkey reaches the age of the firstborn, it may produce the same level of cortisol in stimulating situation, and so do the other younger siblings.

　　Alternative explanation 2: (常见逻辑疑点：样本容量问题)

　　Second, the author cannot safely generalize from 18 rhesus monkeys studiedto all monkeys. Since there may be numerous rhesus monkeys, and the sample pool of 18 of them may be too small to represent the whole species. In addition, rhesus monkeys are only one particular species of monkeys and only may not represent other species. 先分析逻辑再总结 At this point, the result of the study may be explained as that author’s conclusive statement indicates a phenomenon that happens only on those rhesus monkeys.

　　Alternative explanation 3 (which actually contains 3 explanations): (常见逻辑疑点：研究方法—“变量”—问题)

　　Third, in the study of monkeys, it may be because the unfamiliar money provoked the firstborn monkey that the firstborn responded with intense reactions. It is also likely that the unfamiliar money happened to have a smell or an appearance that the firstborn, as a particular monkey, liked or disliked, and simulated the firstborn’s intense reaction. In other words, if a younger sibling also liked or disliked the smell or appearance, he or she would have responded as intensely as the firstborn. Likewise, in the study of humans, it may be because of the strong intimacy between the child and the parent or the child’s strong fear for the parent that the child reacted strongly to the parent’s return.

　　Conclusion

　　The birth order may not be the only plausible explanation for an individual's levels of stimulation. The author cannot be sure of the causation he or she proposes unless the aforementioned alternative explanations are ruled out.