Andrea Sorenson and Dr. James D. Higley, Psychology Department
Initially this project was looking at the effects that multiple short term separations of a mother rhesus macaque from their infant would have on their relationship. More specifically, looking at adoption pairs (an infant raised by a non biological mother) to see if the relationship between the mother and the infant changed differently than the relationship of a mother and their biological infant. The focus of this analysis was looking at the mother/infant pair’s cortisol levels, which are a measure of the body’s physiological response to stress. The hope was to determine whether mother infant pairs with similar cortisol levels, as would be seen in mother/infant pairs biologically related, would respond differently to the separation periods than those with significantly different cortesol levels, as would be seen in adoptive infant pairs. However shortly after analysis began on the data it was determined that there was no significant effect between the separations and the mother/infant pairs relationships, based upon their cortesol levels.
Once it was determined that the previous research was not significant, the focus of the project shifted from the mother infant pairs to the infants themselves. We began looking at how the infants responded under the stress of the separations from their mothers to see if there was a difference between the biologically reared infants and those raised by an adoptive mother. We looked at both the infant’s physiological responses as well as their behavioral responses during the separations comparing them to their base line as well as to one another.
We found that behaviorally adoptive infants performed fewer nervous behaviors than did biologically reared infants. This was illustrated by a significant difference in the number of stereotypic and locomotion behaviors recorded between adoptive and biologically reared infants. Biologically reared infants were found to be performing more locomotion, such as pacing the floor, than adoptive infants. They were also found to perform more stereotypic behaviors, such as thumb sucking and repetitive behaviors. It was also found that adoptive infants perform more environmental exploration than those reared by their biological mother, which is a behavior indicating that the adoptive infants are less nervous or stressed.
When looking at the physiological responses of the infants it was found that adoptive infants responded significantly more than those raised by their biological mothers. We looked at both cortesol and adrenocorticotropic hormone (ACTH), both parts of the neuroendocrine system. Both of these hormones are considered to be indicators of stress, when elevated an individual is considered to be under stress. For the analysis of the infant’s cortesol and ACTH levels we looked at both there levels during the separation periods as well as their levels before and after the separations. ACTH, but not cortesol, was found to be significant. It was found that during all separations, and during the entirety of each separation, those infants that were raised by an adoptive mother had significantly high ACTH levels than those reared by their biological mother.
What this all means is that those reared by an adoptive mother show less stress behaviorally during the separation period than those reared by their biological mother. However, physiologically, those raised by an adoptive mother show greater signs of stress than biologically reared infants as seen by their elevated ACTH levels. This is seemingly a contradiction; however, based upon previous research it seems to indicate that those reared by an adoptive mother do not have the same mother infant relationship as those raised by a biological mother. This goes against the assumption that researchers currently make regarding adoptive infants. This analysis also shows that this is a difference that is only seen during times of stress, there is no significant difference between the two group’s base line values.
While the original research project did not work out, the final results turned out to be quite satisfying. The purpose of doing animal research is to ultimately create a human model from it. It would be impossible to perform the studies on humans that were done for this test. The results of this research go towards creating a human adoption model on the relationship between adopted children and their parents.
After completing the analysis of this data it was our goal to turn it into a poster presentation as well as a published paper. It was presented, in poster format, at the 2009 Mary Lou Fulton conference at Brigham Young University. Here we received third place, out of 19 contestants, for the Psychology section. The poster was also presented at the 2009 American Society of Primatologists (ASP) conference in San Diego California. We are also turning the research into a publication. It is currently in the editing stage, with hopes of submitting it for publication within the next month.
This experience has been one of the most rewarding I have participated in. It has allowed me to expand my knowledge and experience beyond what I could learn in the class room. It has also allowed me to come in contact with leading members in the field of Primatology. This research, and the ORCA grant enabled my attendance to the ASP conference, were the majority of those studying primates in the United States meet to discuss what is currently being done in that field of research. This is a field of research that I would like to pursue in the future and this research has advanced that goal.
With thanks to Whitney Maxwell as my co student researcher and Dr. Higley for mentoring our research. Additional thanks to M. L. Schwantd, S. G. Lindell, C. S. Suomi, and the National Institutes of Health for their contributions to this research.