ARGUMENT 2，互改，谢谢~

lizzylioUID：3791354

Firstborn monkeys, firstborn humans and first-time mother produce more cortisol than other could, to some extent, indicate that birth order affects levels of stimulation through cortisol. But the phenomenon maybe explained by many other elements as well. It is too hasty for the letter to say that the birth order cause the levels of stimulation.

First of all, although cortisol primes the body for increased activity levels, as the author mentioned, such activities might also result from other factors, such as mood in which the individual was. For example, the first-mother is so nervous to give birth to her first kid, so it maybe enhance the stimulation, those monkey who had had serval offspring would be familiar to this process, they probably thought it was a normal activity. Other possible explanation is that the environment in which the individual was brought up. Too cold or too hot will affect the stimulation, if the firstborn kind was born in the cold winter and the younger was born in a moderate weather, in the first few month, the environment can shape the gene in order to adapt the current condition, so the firstborn monkey may be have the high-level stimulation gene caused by environment, in that case the temperature will be the major factor of the high-level stimulation rather than the birth order.

Granted that cortisol levels are closely related to the levels of stimulation, the study above only studied limited situations of stimulation(namely, encountering with unfamiliar monkeys, returning of parents). Therefore, whether the level of cortisol secretion will also be different among sibling under other stimulating condition is open to doubt. The secretion of cortisol only govern activities under certain stimulation. In this case, the explanation of this study could not accurately reflect the actual relationship between the birth order and the individual’s level of stimulation.

In conclusion, notwithstanding the birth order may affect the level of stimulation, the author of the letter should consider and rule out all other possibilities before we could be convinced that the birth order is the vital and only explanation for the individual’s level of stimulation.

写了351个字，实在想不出来论点了。也请大家给点启发~谢谢啦~

小时代12355UID：3801458

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