Moura, A.C. De A. (2003). Sibling age and intragroup aggression in captive

Saguinus midas. International Journal of Primatology, 24(3), 639-652.

The author's study addresses an issue that is relevant to the care and preservation of Callitrichidae. Three families of Saguinus midas were observed for 50 weeks. The author demonstrates that there were differences in the rates of aggression. The differences were linked to sex and age, and become overt under conditions of food shortage. The research was clearly articulated and executed. The data analysis appeared to be appropriate for the data collected. However, the researcher glossed over the challenge of studying captive animals as opposed to wild. Additionally, the author inadequately explained anomalies in the data. The explanation for high intersexual aggression in the group, and that the inverse relationship between aggression received and age was unconvincing. The defense for these occurrences seems to be unrelated to any theoretical position. While these issues are insufficient to invalidate the study, it clearly requires further explication.

Zahed, S.R., Kurian, A.V., & Snowdon, C.T. (2010). Social dynamics and individual plasticity of infant care behavior in cooperatively breeding Cotton-Top Tamarins. American Journal of Primatology, 72, 296 -- 306.

The article is relevant to determining the unit size of captive primates, so that no individual is compromised by the responsibility of infant care. The researchers employed a longitudinal research design and collected data through focal observations and scan samples of care behavior. The observers were highly trained and there was high correlation between the both methods employed. From the data collected, the researchers determined that the individual demonstration of infant care was fluid, and was modified to compensate for variation in social arrangements and conditions throughout litters. The design of this research appears to be robust and employs multiple data collection methods to generate greater validity and reliability. The analysis of the data controlled for sampling anomalies and appropriate statistical tests were conducted on the data. The single challenge in the study may be its applicability to other species or different conditions. This however, does not invalidate the study.