(Medical Xpress) -- University of Michigan researchers have found that women who avoid close relationships and intimacy have smaller hormone responses to emotionally intimate stimuli.
The effects of avoidance were not observed in men or among women exposed to neutral or positive situations, said Robin Edelstein, U-M assistant professor of psychology and the studys lead author.
Edelstein and colleagues assessed changes in estradiol, a steroid hormone associated with attachment and care giving. Estradiol plays important roles in parent-infant bonding, as well as romantic relationships involving adults.
Our findings demonstrate that, for some people, viewing emotionally intimate stimuli can increase estradiol levels, but this was not the case for women who are more detached from close relationships, said Edelstein, who added that its possible these differences contribute to women being emotionally distant.
The fact that estradiol responses among women who are emotionally detached are similar to other womens after viewing neutral or positive stimuli suggests that emotionally detached women may be selectively inattentive to emotional intimacy. It is also possible that theyre paying attention, but still cannot benefit from this kind of intimacy, Edelstein said.
The researchers used data from 229 college students, ranging in age from 18 to 37. The participants reported their experiences in close relationships (including avoidance of intimacy).
Participants provided saliva samples before and after viewing one of three randomly assigned videos clips depicting an emotionally intimate (father-daughter relationship), positive (children engaging in ballroom dancing) or neutral (animal life in the ocean) theme. The researchers assessed whether the depictions of intimacy increased participants level of estradiol.
Among single participants, estradiol levels increased in response to the intimate clips, but this was not the case for participants in relationships. There was no difference among participants after seeing the positive or neutral clips.
Since most of the sample participants were between ages 18-22 and most did not have romantic partners, it is possible that many single individuals considered a parent to be their primary attachment figure. Therefore, they were more likely to identify with the parent-child interaction, Edelstein said.
Its not yet clear why men who are emotionally detached did not show the same estradiol response as women who are emotionally detached. Avoidance did not differ significantly by gender, but men did have somewhat lower estradiol levels to begin with. Its possible that avoidance would influence mens estradiol responses to a different kind of emotionally intimate video, Edelstein said.
Edelstein conducted the study, which appears in the February issue of Hormones and Behavior, with Emily Kean, a graduate student in social work, and William Chopik, a graduate student in psychology.