November 13, 2014
Caitlin: Tues 9 am
Scientific Paper Analysis #3: Physiological and Behavioral Response to Weaning Conflict in Free-Ranging Primate Infants
Tara M. Mandalaywala, James P. Higham, Michael Heistermann, Karen J. Parker, and Dario Maestripieri set out to test the hypothesis that maternal rejection during the weaning period elicits both psychological and energetic stress on primates. They predicted that elevated concentrations of fecal glucocorticoid metabolite (fGCMs) would be associated with increased instances of maternal rejection. They also predicted that increased anxious behaviors would be correlated to elevated concentrations of fGCMs in the primates.
Conducted in Cayo Santiago, Puerto Rico, the research …show more content…
Model one concluded that the infant age (independent variable) had a negative correlation to the fGCM concentration (dependent variable), which was decided to be an unexpected factor that was considered in later tests (p<0.001). The second model, which compared the behavioral variables and mother-infant interactions (independent variables) with fGCM concentration (dependent variable), displayed a number of important results. Distress vocalizations by the infants were correlated to maternal rejection (p<0.001). Self-directed behaviors and maternal interaction variables, including vocalizations showed no relationship (p>0.1). Elevated mother following was correlated positively with time on the nipple (p<0.036). Results also suggest that maternal rejection increased in congruency with increased time spent on the nipple (p<0.001). Additionally, tests of pre and post fGCM concentrations in fecal samples indicate that GC levels were created as a result of behavior and not the other way around. But of all the data perhaps the most important was the positive relationship displayed between the frequency of maternal rejection and the fGCM concentrations (p<0.023). The results of this test sufficiently support the hypothesis that the process of weaning (maternal rejection) may cause psychological or energetic stress. However there was not significant data to support the prediction that there is a positive correlation …show more content…
Using fecal samples to determine GC levels is helpful when considering stress over the course of a few days but is not an accurate indicator of more immediate behavioral responses to maternal rejection. If the experimenters wanted to measure these responses I would propose they use the salivary or blood related tests. These tests provide GC concentrations over a period of a few minutes. Also I appreciated that the mother’s position in the social hierarchy was considered in the study but I found a lack of clarity as to how it was incorporated into the tests, knowing that that could have a significant effect on results. I think it is also important to recognize that data was collected from two separate groups, which could have influenced behavior and mother-infant social structure. Both of which can be shaped by the culture within a particular group. Additionally I found that the environmental conditions of the study were not made clear. If the research was being performed was during a time of heavy drought, for example, that would significantly affect the weaning process. Mothers are not going to be as willing to continue lactation if resources are less abundant. This is due to the heavy energetic cost of lactation. Overall, I found that aspects of the collected data limited the conclusions of the