It has been frequently argued that individuals can experience kin-like bonds with unrelated individuals with whom they have had little or no contact by psychologically transforming them into genetic relatives. This process can be seen when people apply kinship terms to unrelated members of their group (e.g. ‘band of brothers’). This type of ‘kin psychology’ has frequently been used to help explain why men are often willing to make deep sacrifices for unrelated members of their group in war.

– Although much is known about the conditions that cause men to do this, far less is known about how women respond to threats from other groups in general, and especially about which conditions are likely to induce them to make sacrifices for the group, says evolutionary biologist Robert Lynch from the University of Turku.

Lynch is the lead author of the new study conducted by researchers at the University of Turku and Helsinki. According to the researchers, the study provides evidence that group affiliation in women may be influenced by perceived risks to members of their immediate family.

The researchers argue that their results may be best understood within the framework of something called kinship altruism, whereby all organisms, including humans, are more likely to make sacrifices for their close relatives (e.g. siblings or children) than for unrelated individuals.

This study provides insight into the conditions that cause women to view unrelated group members as a member of their own family and develop strong ties to them. Overall the authors suggest that self-sacrifice among women may be particularly sensitive to cues suggesting that family members may be at risk.



– This study supports a widely held view of evolutionary psychologists and anthropologists that group alignment arose out of a psychological adaptation to facilitate cooperation among kin in the face of adversity, says researcher John Loehr from the University of Helsinki who heads the research project.

As the authors point out, perhaps the most interesting finding is the intriguing possibility that it is threats to actual kin, particularly among women, which triggers a willingness to sacrifice for the perceived members of their own group when a conflict between groups arises.

– Kin psychology may be at the root of why women are motivated to make sacrifices for the larger community when faced with a strong outside threat and they perceive that their relatives are at risk. In other words women may be more sensitive to threats from other groups that specifically threaten kin, such that a ‘band of sisters’ is more likely to form around common threats to close relatives, says Lynch.

Although the authors warn that these results should be interpreted with caution and that further research is needed to lock down the specific mechanisms involved and rule out others, a far more general interpretation is that group identification in women may rely more on threats to actual family members which then trigger ‘feelings’ of shared biology with other unrelated individuals in the threatened group.

Well-documented Finnish WWII paramilitary organisation allowed testing hypotheses

This study was conducted by utilizing an unusually well-documented dataset recording the lives of evacuees from Finnish Karelia during World War II to test which factors are positively associated with the likelihood that women volunteer for a woman's paramilitary organization called Lotta Svärd.

On November 30th, 1939 the Soviet Union invaded Finland, marking the beginning of the Winter War and the Karelian population fled to western Finland, although approximately 60% of these evacuees returned to Karelia when it was temporarily recaptured by Finland between 1942 and 1944. Many Karelian women joined the Lotta Svärd organization which was tasked with supporting troops as nurses, air raid spotters, mess personnel and in other auxiliary capacities. By 1944 it included 221,000 volunteers, approximately 10% of the female population of Finland.

Volunteers in the data ranged in age from 7 to 65 years old and were recruited from a variety of family contexts (e.g. single, married, husband served in the war, sisters, brothers, sons and daughters). The different backgrounds and the strictly voluntary nature of participation in the organization allowed the researchers to test some key hypotheses generated by kin psychology in women.

The research article “Self sacrifice and kin psychology in war: threats to family predict decisions to volunteer for a women's paramilitary organization” by Robert Lynch, Virpi Lummaa and John Loehr is currently in press to be published in the next volume of Evolution & Human Behavior. The open access article is available at: https://doi.org/10.1016/j.evolhumbehav.2019.06.001

For more information:

PhD John Loehr

University of Helsinki

tel: +358504366672 or +358504151726

john.loehr@helsinki.fi

PhD Robert Lynch

University of Turku

tel. 929-218-6646

robertflynch@gmail.com

HK

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