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GRE Essay Samples for Argument Task - Rhesus Monkey
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Indrita Ganguly

Content Curator

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.


The research mentioned here showcases how the birth order of an individual is related to the stimulation levels in an overall manner. But here, the author has failed to define what he exactly means by ‘stimulation’ thereby weakening his claims. As we all know stimulations refer to distinctive bodily functions.

The first and foremost claim that the author has given about stimulation which has become unclear is, the relation to stimulations is only caused by the presence and absence of a caregiver. But when it refers to the classic explanation of stimulation then it refers to the arousal caused by excessive bodily movements like increased heart rate and dilated pupils, and this has numerous reasons to be. For instance, the presence of your favorite food or a person whom you adore might create stimulations in you. But these researches haven’t mentioned anything about these actions, and have only mentioned the stimulations caused by common and uncommon instances. They have only mentioned stimulation caused by the occupancy of a person or any exterior deed.

The second drawback that this assumption has is, it is not structured to assess the hypothesis that a person’s birth order affects the level of stimulation. The research focuses more on the stimulation from the absence or attachment caused by that person than their presence. In fact, the research is clearly synonymous with a study where the monkey’s reactions when its caregivers or strangers entered and left the room. This research assessed the monkey’s affectionate level more than their stimulation when their mothers entered and left the room. The first-born monkeys mentioned here are also stated in terms of their relationship with their mother rather than the stimulation they’re feeling. The research also focuses more on first-time mothers having a high levels of cortisol. Though, it must also be noted that the first-born monkeys have a distinctive relationship with their mother than the younger siblings.