UNews - Doug VanderLaan

Unlocking the mystery — Dr. Paul Vasey’s new data analysis reveals insights into male homosexuality

caroline.zentner — Mon, 11 Dec 2023 18:07:04 +0000

A deeper analysis of a decade’s worth of data from Dr. Paul Vasey’s Comparative Sexology Lab at the ��Ѹ��Դ��߿�Ƭ of Lethbridge has lent clarity about the influence of two separate but linked literatures on biological variables influencing male homosexuality.

Vasey, a Professor and Board of Governors Research Chair, and his team of former students (Drs. Doug VanderLaan, Scott Semenyna and Francisco Goméz Jiménez) wanted to determine if there was evidence for both the Fraternal Birth Order Effect (FBOE) and the Female Fecundity Effect (FFE) in data they collected over a decade while working in Samoa.

The FBOE is a widely established finding that each biological older brother a male has increases the probability of homosexuality in that male by 20 to 35 per cent.

The FFE suggests that the female relatives of homosexual males have more children than those of heterosexual males, which provides an evolutionary means to offset the lower reproduction rate of homosexual male relatives. Previous research has also shown support for this hypothesis.

“More recently, people have been saying we need to use different statistical approaches when assessing the FFE that control for the FBOE,” says Vasey. “In order to see if there’s truly a fecundity effect that is occurring, we should see more children in all sibling categories including older sisters, older brothers, younger sisters and younger brothers. In contrast, the FBOE specifically predicts the existence of more older brothers.”

Vasey and his students collected data in the Polynesian island nation of Samoa over a 10-year period working with the support of the fa’afafine community. Fa’afafine are feminine, same-sex attracted males who are recognized as a third gender (neither men nor women) in Samoa.

The team subjected their data to a more robust analysis to determine whether the FBOE occurred in conjunction with the FFE.

“We didn’t find a generalized fecundity effect that influenced all sibling categories,” says Vasey. “We did, however, find that fa’afafine had more older brothers, which is consistent with the fraternal birth order effect.”

Vasey adds that the team’s analysis using a more refined approach is now the fourth to find no evidence for the FFE.

“What we originally thought was support for the FFE was actually just the fraternal birth order effect,” Vasey says. “Without my Board of Governor’s Research Chair, I never would have been able to conduct a decade of fieldwork in Samoa. I’m extremely grateful to the ��Ѹ��Դ��߿�Ƭ of Lethbridge for awarding me my BoG Research Chair and for all the support I have been shown over the years.”

The study was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and has been published in the prestigious journal, Proceedings of the National Academy of Science (PNAS).

The Research Support Fund supports a portion of the costs associated with managing the research funded by the Canadian Institutes of Health Research, Natural Sciences and Engineering Research Council and Social Sciences and Humanities Research Council, such as salaries for staff who provide administration support, training costs for workplace health and safety, maintenance of libraries and laboratories, and administrative costs associated with obtaining patents for inventions.

Groundbreaking paper earns Vasey lab prestigious award

trevor.kenney — Mon, 10 Nov 2014 21:25:13 +0000

A pioneering research paper from Dr. Paul Vasey’s Laboratory of Comparative Sexuality at the ��Ѹ��Դ��߿�Ƭ of Lethbridge has been recognized by the Society for the Scientific Study of Sexuality (SSSS) as the winner of the 2013 Ira and Harriet Reiss Theory Award for best theoretical paper in sexology.

Dr. Paul Vasey says the award is both gratifying and reflective of the nature of research being undertaken at the U of L. Photo by Mary Kavanagh

The paper, Male Androphilia in the Ancestral Environment: An Ethnological Analysis, examines the evolution of male same-sex sexuality.

“The paper conceptualizes and tests a model for the natural selection and persistence of male same-sex attraction based upon novel cross cultural data, and represents an important addition to knowledge in this area,” says Dr. William Fisher, Chair of the Ira and Harriet Reiss Theory Award Committee.

The manner in which male same-sex sexual attraction manifests publicly varies across cultures. Vasey says that in Euro-American societies, we are most accustomed to seeing the "gay" form, but in many non-Western cultures, a transgendered form exists. The group’s work indicates that the transgendered form likely evolved first.

“This finding is important because it suggests that the transgender form might be the best model when testing evolutionary theories for male same-sex sexuality,” says Vasey. “In this regard, we felt our paper was a bit of a game changer with respect to how research on this topic will be conducted in the future.”

The authors also demonstrate that elevated investment in kin by transgendered males may have played a role in the evolution of same-sex sexuality.

Vasey says the award is both gratifying and reflective of the nature of research being undertaken at the U of L.

“It's a great honour to share this award with my former doctoral student, Doug VanderLaan, and my former Honours student, Zhiyuan (Lance) Ren. We spent almost two years working on this paper together and I'm extremely proud of the final product,” says Vasey. “I think this work is a great example of how both graduate and undergraduate training is integrated into my lab’s research program, and is indicative of the high calibre of research being conducted at the U of L.”

Fisher explains that the purpose of the Ira and Harriet Reiss Theory Award is to encourage and support advances in the development of social science theory in the field of sexual science.

“The goal is to explain human sexuality so as to increase our knowledge and thereby our ability to handle the sexual problems we face in the U.S. and other societies,” he says. “The winner of the annual award is selected by reviewing the previous year’s published articles, chapters and books in which social science theoretical explanations of human sexual attitudes and behaviours are both developed and tested.”

The award selection was also approved by the Foundation for the Scientific Study of Sexuality (FSSS). The authors will present their work at the 2015 meeting of SSSS.

U of L psychologists examine sexual orientation through Samoan study

trevor.kenney — Tue, 09 Feb 2010 18:34:35 +0000

Male homosexuality doesn't make complete sense from an evolutionary point of view, prompting a pair of evolutionary psychologists from the ��Ѹ��Դ��߿�Ƭ of Lethbridge to venture to the Pacific island of Samoa to try and discover why.

Associate professor Dr. Paul Vasey (Psychology/Behaviour and Evolution Research Group) and PhD candidate Doug VanderLaan of the ��Ѹ��Դ��߿�Ƭ of Lethbridge chose Samoa because males who prefer men as sexual partners are widely recognized and accepted there as a distinct gender category – called fa'afafine, neither man nor woman.

It appears that the trait of homosexuality is heritable, but because homosexual men are much less likely to produce offspring than heterosexual men, shouldn't the genes for this trait have been extinguished long ago?

What value could this sexual orientation have, that it has persisted for eons even without any discernible reproductive advantage?

One possible explanation is what evolutionary psychologists call the "kin selection hypothesis."

What that means is that homosexuality may convey an indirect benefit by enhancing the survival prospects of close relatives. Specifically, the theory holds that homosexual men might enhance their own genetic prospects by being helpers in the nest.

By acting altruistically toward nieces and nephews, homosexual men would perpetuate the family genes, including some of their own.

The fa'afafine of Samoa tend to be effeminate, and exclusively attracted to adult men as sexual partners. This clear demarcation makes it easier to identify a sample for study.

Past research has shown that the fa'afafine are much more altruistically inclined toward their nieces and nephews than either Samoan women or heterosexual men.

They babysit a lot, tutor the kids in art and music, and help out financially – paying for medical care, education and so forth.

In a new study, Vasey and VanderLaan set out to unravel the psychology of the fa'afafine, to see if their altruism is targeted specifically at kin rather than kids in general.

The findings, reported on-line this week in the journal Psychological Science, lend strong support to the kin selection idea.

Compared to Samoan women and heterosexual men, the fa'afafine showed a much weaker link between their avuncular, or uncle-like behavior, and their altruism toward kids generally.

This cognitive dissociation, the scientists argue, allows the fa'afafine to allocate their resources more efficiently and precisely to their kin – and thus enhance their own evolutionary prospects.

For more information about this study, contact Paul Vasey at paul.vasey@uleth.ca, or follow this Notice Board link for a deeper examination of the issue. As well, check out the programs offered by the U of L's Department of Psychology.

UNews - Doug VanderLaan

Unlocking the mystery — Dr. Paul Vasey’s new data analysis reveals insights into male homosexuality

Related Topics

Groundbreaking paper earns Vasey lab prestigious award

Related Topics

U of L psychologists examine sexual orientation through Samoan study

Related Topics