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

The arguer has linked individal’s level of stimulation to birth order and put forwarded several examples which he hoped to explain his conclusion. The argument and examples looks plausible at first glance, but closer analysis reveals that examples provided aren’t sufficient to come to arguer’s conclusion. Rather there may be several other factors working in support of increasing level of stimulation other than birth order.

To begin with, the study shows that first-time mother monkey had higher level of cortisol compared to others who had several offspring. However, we are talking about offspring here and not their mothers. Rather this evidence shows that it is likely that stimulation level depend on one’s individuality. It is possible even if mother monkey’s stimulation level is compared with several other first-time mother monkey, each time the former one is declared to have higher concentration of cortisols. Same can be said about the example of first born humans provided here.

Second, the age difference between monkeys that are considered can play a major role in this case. It is likely that the first-born monkeys are much older than younger ones who are just few months old. The stimulation factor grows with their age. The older one consumes more food, invlove in many activities like playing and searching for foods with others. So it would be a mistake to compare first-born with younger ones whose stimulation level is still increasing.

Moreover, particular situation can cause an increased stimulation level. From the result of the study, it is clear that situations like meeting with an unfamiliar monkey or return of a parent after a long time is kind of special to these species. These unfamiliar situations happens seldom in one’s life and is bound to cause more excitation and as a result produces more cortisols. Younger ones being having a lower maturity level may be unable to understand the significance of the situations. Also the study excludes the information of the activities performed by the monkeys just before the experiment. There will be significant difference between cortisol level if younger monkeys are sleeping and first-born are jumping around from tree to tree.

In conclusion, there are several other factors that contribute to stimulation level. The arguer has provided three study results none of which shows concrete evidence that the arguer has proposed. In fact, arguments specified above are more plausible and can support the author’s study results. To substantiate his argument, the author could have provided results among first-born and younger monkeys of comparable ages by ensuring that ages doesn’t play any role here or making monkeys face a similar situation after forcing them to sleep to make sure that situations are same for all of them. In absence of above, the argument remains unconvincing to readers.