Current research in the CAF laboratory includes the following.
The University of Michigan Gelada Research Project (UMGRP)
This project, directed by Dr. Jacinta Beehner (Assistant Professor in the Departments of Anthropology and Psychology at the University of Michigan), examines the evolution of social behavior in free-ranging primates. Currently, our research is focused on sexual selection in male geladas (a close relative of baboons), and we are specifically examining the hormonal bases behind various behaviors that are related to acquiring, choosing, and/or keeping a mating partner in geladas. Such behaviors include dominance, aggression, and "quality" signaling. Perhaps the most striking feature of the gelada (also known as the "bleeding heart baboon") is a flame-red patch of skin on the chest and neck. In females, chest patch color changes with reproductive condition, growing brighter close to ovulation and as pregnancy progresses. In males, however, changes in chest patch color appear to be rank-based, with dominant males exhibiting the brightest patches. We are investigating the possible hormonal causes of the "bleeding heart" in a group of habituated geladas living in the Simien Mountains National Park, of Ethiopia.
Male geladas are the showy sex with flowing manes and bright red chest patches. This chest patch may serve as a badge of quality or condition. Colored patches in many animals are considered "badges of status" when the size or color of the patch is associated with the dominance rank or fighting ability of the bearer [Madsen and Masataka 1987; Møller 1987; Rohwer 1975]. Our working hypothesis is that males assess each other based on physical endurance, vocalizations, and/or chest patch color. Furthermore, as the development of badges of status is often under the control of steroid hormones, it seems probable that steroid hormones play a role in the intensity of the color. Although suggestions that the gelada "bleeding heart" is related to status and/or hormones are not new, these hypotheses have never actually been tested.
We obtain all of our hormone samples non-invasively by collecting fecal samples from known individuals in the wild. We then extract steroid hormones from fecal samples while in the field (mainly testosterone and glucocorticoid metabolites). Samples are then further extracted and analyzed in our hormone laboratory at the University of Michigan. Although we currently are analyzing only testosterone and glucocorticoids from males, we are extending this project to also include reproductive hormones (estrogens and progestins) from females.
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Steve Stanton (Graduate student in the Department of Psychology at the University of Michigan)
Steve is interested in relationships between biology, personality, motivation, and emotion. Broadly, his current research is focused on non-conscious motivation (power, sex, and affiliation motives) and how differences in motivation are related to differences in steroid hormone (testosterone, estrogen, cortisol, progesterone) levels. His research goes beyond basal correlations between personality and hormones by exploring how social events (dominance contests, watching movies) can drive hormone changes as a function of an individual's motivational profile. Current projects include neuroimaging research on moderating influences of testosterone on brain activation in response to dominance signals, the development of a non-conscious measurement of sexual motivation, and endocrine variation in patterns of attachment.
Amy Lu (Graduate student in the Interdepartmental Doctoral Program in Anthropological Sciences at Stony Brook University)
Amy's doctoral research project (advisor: Carola Borries) is designed to test hypotheses concerning the relationships between social rank, stress hormones, and reproduction in wild female Phayre's leaf monkeys (Trachypithecus phayrei) living in the Phu Khieo Wildlife Sanctuary in Thailand. Specifically, her study has three goals:
- to characterize behavioral variables that may influence glucocorticoid secretion in high- and low-ranking females,
- to assess how the distribution of these behaviors shapes rank-related hormone patterns, and
- to assess the relationship between glucocorticoids, cycle length, and conceptive probability.
It is hypothesized that because female Phayre's leaf monkeys are characterized by a dominance hierarchy that is maintained individualistically and unstable through time, there will be important social stress associated with high rank. These stressors (of high-ranking individuals) will ultimately outweigh those associated with low rank. More generally, Lu is interested in how the relationship between social rank and glucocorticoids might vary across species with different dominance styles, and how elevated glucocorticoids might benefit, rather than hinder female reproduction. Her project is part of a long-term study of the socio-ecology of Phayre's leaf monkeys directed by Andreas Koenig and Carola Borries (Department of Anthropology, Stony Brook University).
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Hormones, Behavior and Parent-Infant Relationships (HBPIR)
The purpose of this project, directed by Brenda Volling (professor in the Department of Psychology at the University of Michigan), is to examine the associations between hormones (e.g., testosterone, cortisol, and progesterone) and the quality of parent-infant interaction tasks occurring during the 12- and 13-month lab visits of the Family Transitions Study.
Also, we are interested in whether the brief separation between parents and infants during our social skills assessment may be more stressful for some children and parents than others and hope to capture this by looking at the stress hormone, cortisol. We are particularly excited about the HBPIR substudy because there is so little research examining the links between hormone levels and parent-infant relationships. For more information on additional projects in the Volling lab, please visit http://sitemaker.umich.edu/family.relationships.project/research.
Ekjyot Saini is a research assistant with Dr. Brenda Volling. Ekjyot received her Bachelor of Arts in Brain, Behavior and Cognitive Science and History from the University of Michigan. As an undergraduate she worked with Dr. Oliver Schultheiss on the role of hormones in social contexts by examining the relationship between steroid hormones and motivational traits. Currently she is working with Dr. Brenda Volling to study the role of steroid hormones in family relationships through attachment behaviors between parents and infants.
A Renewed Look at Cognitive Dissonance: Culture, Choice Justification, and Biological Stress
The purpose of this project, directed by Shinobu Kitayama (Professor in the Department of Psychology), is to take a renewed look at cognitive dissonance from both cultural and biological perspectives.
The dissonance theory claims that by choosing between two equally attractive options individuals experience negative arousal, which in turn is reduced by justification of the choice. It therefore predicts a negative association between negative arousal and choice justification. With Sasha Kimel (Graduate Student in Psychology), Kitayama has recently obtained the first evidence for this association with salivary cortisol as a measure of negative arousal. Caucasian and Asian American participants were offered a choice between two equally attractive CDs. Choice justification was assessed in terms of spreading of rankings of the chosen and the rejected CDs. Half of participants were unobtrusively primed with scrutiny by other people (the "public" choice condition) whereas the other half were not given this priming manipulation (the "private" choice condition). Replicating previous evidence from the Kitayama lab, Caucasian Americans showed a significant choice justification effect only in the "private" condition. In contrast, Asian Americans showed such an effect only in the "public" condition. Regardless of choice condition and ethnicity, salivary cortisol generally decreased over the 20-minute period after the choice. As predicted, however, this decrease was more pronounced for those who justified their choices more. The association was observed both at 5 minutes and at 20 minutes after the choice.
We believe that the interface between culture and biology is an exciting new area of empirical inquiry that can shed further light on mutual influences between culture and the mind. For further inquiry, visit the Culture and Cognition website.
Sasha Kimel is a doctoral student in Social Psychology at the University of Michigan. Sasha received her Bachelor of Arts in Psychology from the University of British Columbia. She is currently interested in research about in the way in which individuals are shaped by culture, and how individuals simultaneously affect their culture. In particular, she is interested in cultural variations in cognition and representations of the self and in the psychological consequences of globalization. She is also interested in the implications of culture specific psychological processes for health and well-being.
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