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 situ

In this argument author is publishing the result of behavioral study performed on the rhesus monkeys and firstborn humans. The results is unconvincing as it has many loop holes and can be undermined by many explanations.

Firstly, study was performed on eighteen rhesus monkeys which is unacceptable number of samples to study any habitat. If writer would have specified population of rhesus monkeys in existence and if the samples were in commensurate with the population, this could have strengthen or weaken the argument. If we are studying behavior of any species we need ensure that we have covered at least thousands of samples before concluding. If writer would have specified about rare existence of rhesus monkeys it would have supported the results. Writer didn't specify habitat of monkeys which were study. It may not hold true that monkeys from other habitat will respond to study in same way as rhesus monkeys.

It may hold true that few firstborn infant monkeys produces high-level of chromosomes but here as well author failed to mention that number of firstborn infant monkeys considered during study. Even if all eighteen rhesus monkeys were new born still they are insufficient to determine the behavior. Author repeatedly fail to provide the numbers which makes this study involved. Author failed to expound the reason for high levels of cortisol in the firstborn. No pragmatic evidence is provided to strengthen the argument.

In case of firstborn human behavior study, there are thousands of baby born every seconds. Human behavior is most complex and unpredictable. Some babies may produce high levels of cortisol in situation when parents return after long time, but doesn't that hold true for only firstborn babies. My experience says it hold true for all babies. My brother just had second baby who is more excited then his sibling when he sees parents and his smile is worth watching. Human behavior is involved and cannot be studied or predicted. We humans ourselves raise our kids in our own way. Parents who are attached to their kids, kids responds with same affection and love irrespective they are firstborn or second.

Lastly, study on eighteen rhesus monkeys, undisclosed number of firstborn monkey and humans cannot be applied on all the species. Monkeys and humans behavior have lots of things in common. Study result would have been convincing and hold true if more diverse species were part of the study. There are extreme behavioral differences from one species to other. Carnivorous animals are detached from their babies from birth so that they can be independent and self-sufficient.

To conclude, lack of details like sample count and study of similar inhabitant make the argument weak and implausible.