"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

Essay topics:

"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.

While it may be true that birth order affects an individual’s level of stimulation, the author fails to provide a cogent argument for this claim. Their explanation relies on a number of key assumptions lacking the requisite evidence for support. Without such evidence, the author's conclusion that first-born monkeys and potentially first-born humans reach higher levels of stimulation is not the only compelling explanation of the facts presented.

Because the study had a sample size of just eighteen rhesus monkeys, extrapolations from these results are limited in scope, and it may simply be that the observed variations in cortisol levels reflect such existing variation in the rhesus monkey population. If there were only eighteen monkeys in total, then there must have been even smaller sized groups of firstborn and “later-born” monkeys. The common minimum recommended threshold for sample size to achieve statistically meaningful results is thirty, but there may well have been fewer than ten monkeys within the firstborn or “later-born” groups. As such, the fact that firstborn infant and first-time mother monkeys had higher average levels of cortisol could simply be attributed to the natural variation in cortisol levels among rhesus monkeys. Without any information about studies on humans or evidence for correspondence between human and monkey cortisol levels, the results of this study certainly cannot be used to draw any conclusions about humans either.

Setting aside the sample size concerns, it is still possible that any elevation of cortisol levels in firstborn monkeys may be due to the fact that these firstborn infants are older than their siblings. The author did not describe whether the study ensured each infant was only evaluated once reaching a fixed age, so cortisol levels could have been assessed in monkeys spanning a range of ages. If that was the case, then higher cortisol levels in firstborn monkeys may be an effect of older age rather than some biological difference due to birth order. For instance, perhaps young rhesus monkeys develop stronger responses to stimulation as they grow throughout their childhood. To determine whether this or the author’s proposed explanation is valid, a more controlled study would need to be performed where each monkey is evaluated at the same age, or better yet, in adulthood when all can be certain to have already met the same developmental milestones.

Finally, even if it is accepted that firstborn monkeys display higher cortisol levels, this may point to structural differences in endocrine systems instead of suggesting higher levels of stimulation. It is true that cortisol prepares the body for activity, but it is only one of many hormones responsible for response to stimulation. For example, adrenaline is another key ingredient in an individual’s preparation for action. Since the author noted that first-time mother monkeys had higher levels of cortisol in their system, it is possible that this chemical environment affects the operation of the endocrine system in their offspring, explaining the higher cortisol levels in firstborn infant monkeys. Because there is no evidence that the study investigated other components of a stimulation response, there is no reason to believe from the high cortisol levels alone that the firstborn infants overall had greater levels of stimulation.

It may well be that firstborn monkey offspring and perhaps even human offspring have higher levels of stimulation than their younger sibling counterparts. However, from the sparse facts presented, there is simply not enough evidence accumulated to posit this claim. In order to rule out the alternative explanations presented, a more rigorous study would need to be performed to clarify the interpretation of the results.

Votes
Average: 6.6 (1 vote)
Essay Categories

Comments

Grammar and spelling errors:
Line 1, column 279, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'authors'' or 'author's'?
Suggestion: authors'; author's
...for support. Without such evidence, the authors conclusion that first-born monkeys and ...
^^^^^^^
Line 6, column 1, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...met the same developmental milestones. Finally, even if it is accepted that fir...
^^^

Transition Words or Phrases used:
but, finally, first, however, if, may, so, still, then, well, while, for example, for instance, it is true

Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments

Performance on Part of Speech:
To be verbs : 31.0 19.6327345309 158% => OK
Auxiliary verbs: 16.0 12.9520958084 124% => OK
Conjunction : 13.0 11.1786427146 116% => OK
Relative clauses : 16.0 13.6137724551 118% => OK
Pronoun: 37.0 28.8173652695 128% => Less pronouns wanted
Preposition: 68.0 55.5748502994 122% => OK
Nominalization: 29.0 16.3942115768 177% => OK

Performance on vocabulary words:
No of characters: 3256.0 2260.96107784 144% => OK
No of words: 594.0 441.139720559 135% => OK
Chars per words: 5.48148148148 5.12650576532 107% => OK
Fourth root words length: 4.93681225224 4.56307096286 108% => OK
Word Length SD: 3.05595205709 2.78398813304 110% => OK
Unique words: 268.0 204.123752495 131% => OK
Unique words percentage: 0.451178451178 0.468620217663 96% => OK
syllable_count: 1011.6 705.55239521 143% => OK
avg_syllables_per_word: 1.7 1.59920159681 106% => OK

A sentence (or a clause, phrase) starts by:
Pronoun: 6.0 4.96107784431 121% => OK
Interrogative: 0.0 0.471057884232 0% => OK
Article: 8.0 8.76447105788 91% => OK
Subordination: 8.0 2.70958083832 295% => Less adverbial clause wanted.
Conjunction: 4.0 1.67365269461 239% => Less conjunction wanted as sentence beginning.
Preposition: 7.0 4.22255489022 166% => OK

Performance on sentences:
How many sentences: 21.0 19.7664670659 106% => OK
Sentence length: 28.0 22.8473053892 123% => The Avg. Sentence Length is relatively long.
Sentence length SD: 54.146689147 57.8364921388 94% => OK
Chars per sentence: 155.047619048 119.503703932 130% => OK
Words per sentence: 28.2857142857 23.324526521 121% => OK
Discourse Markers: 5.04761904762 5.70786347227 88% => OK
Paragraphs: 5.0 5.15768463074 97% => OK
Language errors: 2.0 5.25449101796 38% => OK
Sentences with positive sentiment : 10.0 8.20758483034 122% => OK
Sentences with negative sentiment : 5.0 6.88822355289 73% => OK
Sentences with neutral sentiment: 6.0 4.67664670659 128% => OK
What are sentences with positive/Negative/neutral sentiment?

Coherence and Cohesion:
Essay topic to essay body coherence: 0.339216795771 0.218282227539 155% => OK
Sentence topic coherence: 0.111242830016 0.0743258471296 150% => OK
Sentence topic coherence SD: 0.0585186130574 0.0701772020484 83% => OK
Paragraph topic coherence: 0.203498215658 0.128457276422 158% => OK
Paragraph topic coherence SD: 0.0554047142485 0.0628817314937 88% => OK

Essay readability:
automated_readability_index: 18.5 14.3799401198 129% => OK
flesch_reading_ease: 34.6 48.3550499002 72% => OK
smog_index: 11.2 7.1628742515 156% => OK
flesch_kincaid_grade: 15.4 12.197005988 126% => OK
coleman_liau_index: 14.8 12.5979740519 117% => OK
dale_chall_readability_score: 8.96 8.32208582834 108% => OK
difficult_words: 148.0 98.500998004 150% => OK
linsear_write_formula: 14.5 12.3882235529 117% => OK
gunning_fog: 13.2 11.1389221557 119% => OK
text_standard: 15.0 11.9071856287 126% => OK
What are above readability scores?

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Rates: 66.67 out of 100
Scores by essay e-grader: 4.0 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: 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.