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.
In the letter, the author suggests that birth order has an impact on an individual’s levels of stimulation. The conclusion is based on the facts that are observed in a recent study. At first glance, the argument seems to be plausible; however, there are different ways of interpreting the observed facts, which challenge the argument in the letter. Consequently, the conclusion is not cogent.
With the fist fact that the firstborn infant monkeys produce up to twice as much of the hormone cortisol as do their younger siblings. The letter correlates this phenomenon to the birth order suggesting that because these monkeys are born first, they are more sensitive to stimulations. However, there could be other explanations for this fact. It could result from less familiar with the soundings. As mentioned in the letter, in a situation such as encountering unfamiliar monkeys, if an infant monkey has only its parents around it and without siblings, it will encounter less situations, especially dramatic ones, compared with their younger siblings. They are born having old brother or sisters around and will subsequently get more chances of seeing and experiencing various situations. They thus react less intensively to the stimulations. If this is actually the reason, when the firsborn monkey is taken away, the second-born one, who is now alone without siblings, will also produce much higher hormone cortisol when facing stimulations. In other words, the birth order is not the cause.
Similarly, as for the fact that first born humans also produce high levels of cortisol in stimulating situations, this is also credited to the birth order by the letter. Yet, the alternative explanation is their limited sources of getting attention. When they are the only child, they mainly get the attention from their parents. By contrast, being not the only child, a younger child who gets attention from both the patents and the older sibling(s). It therefore does not respond to stimulated situations, such as the return of a parent after absence, as strong as the only child. If this is the reason, the birth order does not lead to the difference in levels of cortisol. Rather, the fact that it is the only child does.
Last, the letter implies that the reason for the first-time mother monkeys to have higher levels of cortisol is because of the order, that is, they are pregnant for the first time. Yet, they are more sensitive to simulations could result from lacking experience. If one has never experienced pregnancy before, they do not know how to deal with some symptoms or changes of the body. Because of not knowing what to do, they are more impressionable to stimulations. For comparison, those who have already experienced and learnt how to deal with different situation are more calm when tackling stimulations. Consequently, they will produce lower levels of cortisol. To further explain that birth order is not the reason, imagine a situation where some monkeys have had offspring previously. Still, due to a long interval, they will still produce higher levels of cortisol.
In conclusion, birth order could precisely explain the facts showed in the study. To make the explanation plausible, the letter needs to provide sufficient evident in order to exclude other possible accounts. Without doing so, the argument in the letter is unsound.
Comments
Essay evaluation report
This is the most difficult argument topic from new GRE. You got some points but not exactly.
The goal of the statement is to prove:
The birth order can affect an individual's levels of stimulation.
Then it gives three assumptions:
(1) 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;
(2) Firstborn humans also produce relatively high levels of cortisol in stimulating situations (such as the return of a parent after an absence).
(3) The study also found that during pregnancy, first-time mother monkeys had higher levels of cortisol than did those who had had several offspring."
So the alternative explanations could be:
1. Maybe not because of the birth order, but because first born infant monkeys,first-time mother monkeys，and firstborn humans all belong to same biological species - primates.
2. The age difference can play a major role. Maybe different siblings produce different amounts of hormone cortisol.
3. Maybe it is related to particular situations because the conditions are like: meeting with an unfamiliar monkey, reunion with a parent after an absence, and first-time birth of baby monkeys.
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Attribute Value Ideal
Final score: 3.0 out of 6
Category: Satisfactory Excellent
No. of Grammatical Errors: 0 2
No. of Spelling Errors: 0 2
No. of Sentences: 31 15
No. of Words: 549 350
No. of Characters: 2728 1500
No. of Different Words: 234 200
Fourth Root of Number of Words: 4.841 4.7
Average Word Length: 4.969 4.6
Word Length SD: 2.646 2.4
No. of Words greater than 5 chars: 191 100
No. of Words greater than 6 chars: 144 80
No. of Words greater than 7 chars: 96 40
No. of Words greater than 8 chars: 65 20
Use of Passive Voice (%): 0 0
Avg. Sentence Length: 17.71 21.0
Sentence Length SD: 8.093 7.5
Use of Discourse Markers (%): 0.548 0.12
Sentence-Text Coherence: 0.265 0.35
Sentence-Para Coherence: 0.449 0.50
Sentence-Sentence Coherence: 0.052 0.07
Number of Paragraphs: 5 5
Grammar and spelling errors:
Line 3, column 576, Rule ID: FEWER_LESS[2]
Message: Did you mean 'fewer'? The noun situations is countable.
Suggestion: fewer
...and without siblings, it will encounter less situations, especially dramatic ones, c...
^^^^
Discourse Markers used:
['actually', 'also', 'consequently', 'first', 'however', 'if', 'second', 'similarly', 'so', 'still', 'therefore', 'thus', 'as for', 'in conclusion', 'such as', 'in other words']
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance in Part of Speech:
Nouns: 0.214057507987 0.25644967241 83% => OK
Verbs: 0.151757188498 0.15541462614 98% => OK
Adjectives: 0.0958466453674 0.0836205057962 115% => OK
Adverbs: 0.0670926517572 0.0520304965353 129% => OK
Pronouns: 0.0335463258786 0.0272364105082 123% => OK
Prepositions: 0.113418530351 0.125424944231 90% => OK
Participles: 0.0415335463259 0.0416121511921 100% => OK
Conjunctions: 2.80002023874 2.79052419416 100% => OK
Infinitives: 0.0303514376997 0.026700313972 114% => OK
Particles: 0.00159744408946 0.001811407834 88% => OK
Determiners: 0.110223642173 0.113004496875 98% => OK
Modal_auxiliary: 0.0143769968051 0.0255425247493 56% => OK
WH_determiners: 0.0239616613419 0.0127820249294 187% => OK
Vocabulary words and sentences:
No of characters: 3373.0 2731.13054187 124% => OK
No of words: 549.0 446.07635468 123% => OK
Chars per words: 6.14389799636 6.12365571057 100% => OK
Fourth root words length: 4.84053189512 4.57801047555 106% => OK
words length more than 5 chars: 0.367941712204 0.378187486979 97% => OK
words length more than 6 chars: 0.28233151184 0.287650121315 98% => OK
words length more than 7 chars: 0.185792349727 0.208842608468 89% => OK
words length more than 8 chars: 0.138433515483 0.135150697306 102% => OK
Word Length SD: 2.80002023874 2.79052419416 100% => OK
Unique words: 241.0 207.018472906 116% => OK
Unique words percentage: 0.43897996357 0.469332199767 94% => More unique words wanted or less content wanted.
Word variations: 51.4219404289 52.1807786196 99% => OK
How many sentences: 31.0 20.039408867 155% => OK
Sentence length: 17.7096774194 23.2022227129 76% => OK
Sentence length SD: 50.4543147532 57.7814097925 87% => OK
Chars per sentence: 108.806451613 141.986410481 77% => OK
Words per sentence: 17.7096774194 23.2022227129 76% => OK
Discourse Markers: 0.516129032258 0.724660767414 71% => OK
Paragraphs: 5.0 5.14285714286 97% => OK
Language errors: 1.0 3.58251231527 28% => OK
Readability: 45.9428286033 51.9672348444 88% => OK
Elegance: 1.46202531646 1.8405768891 79% => OK
Coherence and Cohesion:
Essay topic to essay body coherence: 0.510741396744 0.441005458295 116% => OK
Sentence sentence coherence: 0.124052175205 0.135418324435 92% => OK
Sentence sentence coherence SD: 0.0829306579069 0.0829849096947 100% => OK
Sentence paragraph coherence: 0.506932209379 0.58762219726 86% => OK
Sentence paragraph coherence SD: 0.145550582934 0.147661913831 99% => OK
Sentence topic coherence: 0.191076668656 0.193483328276 99% => OK
Sentence topic coherence SD: 0.112830818964 0.0970749176394 116% => OK
Paragraph paragraph coherence: 0.429168481695 0.42659136922 101% => OK
Paragraph paragraph coherence SD: 0.115238409266 0.0774707102158 149% => OK
Paragraph topic coherence: 0.375219604552 0.312017818177 120% => OK
Paragraph topic coherence SD: 0.0595422497124 0.0698173142475 85% => OK
Task Achievement:
Sentences with positive sentiment : 5.0 8.33743842365 60% => OK
Sentences with negative sentiment : 6.0 6.87684729064 87% => OK
Sentences with neutral sentiment: 20.0 4.82512315271 414% => Less neutral sentences wanted.
Positive topic words: 0.0 6.46551724138 0% => More positive topic words wanted.
Negative topic words: 3.0 5.36822660099 56% => OK
Neutral topic words: 8.0 2.82389162562 283% => OK
Total topic words: 11.0 14.657635468 75% => OK
What are sentences with positive/Negative/neutral sentiment?
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More arguments wanted.
Rates: 50.0 out of 100
Scores by essay e-grader: 3.0 Out of 6 -- The score is based on the average performance of 20,000 argument essays. This e-grader is not smart enough to check on arguments.
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Note: This is not the final score. The e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.