Original Article
Kin and kinship psychology both influence cooperative coordination in Yasawa, Fiji

https://doi.org/10.1016/j.evolhumbehav.2016.09.004Get rights and content

Abstract

Genes shared through common ancestry are among the oldest social bonds. Despite these ancient roots, humans often co-opt the psychology of genetic relatedness and extend it to genetically unrelated others through culturally-acquired kinship systems. We investigate how genealogical relatedness and kinship norms might mutually support or oppose each other within a known kin network in Yasawa, Fiji. Yasawans' reliance on intensive, kin-based cooperation for daily life makes Yasawan kinship an interesting test case to compare the effects of genealogy and kinship norms. Confirming qualitative ethnographic claims, we find that Yasawan kin terms can be described in two dimensions of respect/closeness and joking/authority. Individual players use different strategies for genealogical relatives and non-relatives by making economic game choices that are increasingly beneficial to partners who share a higher percentage of genes through common ancestry. However, pairs of players are most successful in coordinating their game choices despite conflicting self-interests based upon kinship norms relevant to hierarchy. Thus, while genealogical relatedness may boost generosity, the extra behavioral structuring from kinship norms facilitates more productive but difficult coordinated action even when communication is not possible.

Introduction

They say that blood is thicker than water. Though this phrase is often used to emphasize the importance of family, its original meaning was the opposite: that the blood of the covenant (with God – connections made by choice) is thicker than the water of the womb (connections made through birth; Jack, 2005). The paradoxical history of even this simple idiom encapsulates the paradoxical nature of kin psychology. Though social ties through common ancestry are among the oldest forms of sociality, the psychology of kinship across human societies regularly co-opts sentiments geared toward genetic relatives and extends them to unrelated strangers.

Kin selection (Eberhard, 1975, Hamilton, 1964, Nowak, 2006, Read and Grushka-Cockayne, 2011, Smith, 1964) explains how some traits can evolve in a population through an organism's own reproductive success and their genetic relatives' success. This inclusive fitness should favor traits that boost altruism toward genetic relatives. Kin-selected traits may include cognitive and psychological mechanisms that direct our interactions with genetic relatives (Fessler and Navarrete, 2004, Lieberman et al., 2007, Schaich Borg et al., 2008; but see also Glassman et al., 1986, Kurzban et al., 2012); a suite of psychological traits that forms kin psychology.

Along with psychological mechanisms for managing interactions with genetic relatives, human kinship also involves extensive cooperation with genetic non-relatives. Humans in every society have culturally evolved kinship systems - complex arrays of norms that harness kin psychology and apply it to govern behavior toward others of all degrees of genetic similarity. These kinship norms can make kin-focused psychological mechanisms more potent, extend activation to include genetic non-relatives, and suppress activation toward actual genetic relatives (Henrich, 2015). Importantly, this array of norms can expand cooperation beyond genes. Kinship systems also include terminological systems – sets of labels that we use to identify various others to whom we should behave in a certain way – that constantly re-enforce the kinship norms through daily use. The ways that kin psychology extend feelings of familial interconnectedness may itself be a building block to other norm systems like economic markets and resource trade (Henrich et al., 2010, Malinowski, 1932, Seabright, 2010); religious systems (Graham and Haidt, 2010, Johnson, 2009, Johnson and Bering, 2006, Norenzayan, 2013, Sosis and Ruffle, 2004, Wilson, 2003); and secular governments (Kay et al., 2010, Norris and Inglehart, 2004, Shariff and Norenzayan, 2007) that support ever expanding, increasingly complex societies. Kinship norms provide just one of the many norm systems we use to facilitate cooperation (Kimbrough and Vostroknutov, 2013, Sripada and Stich, 2006).

Despite evolutionarily ancient roots, evidence for the specific effects of kin selection on human psychology is mixed. Some observational studies suggest that kin selection can boost cooperation, especially in small-scale societies (Apicella et al., 2012, Lieberman et al., 2007, Morgan, 1979). Other studies suggest that kin selection may only explain a limited amount of human cooperation (Laland et al., 2010, Richerson and Boyd, 2006, Richerson et al., 2010) with reciprocity acting as a stronger motivation – especially in small-scale societies (Allen-Arave et al., 2008, Gurven, 2004a, Jaeggi and Gurven, 2013, Kaplan and Hill, 1985, Patton, 2005, Winterhalder, 1996). Still others claim that adaptations ascribed to kin selection may be described by more general processes of group selection (Lehmann et al., 2007, Nowak et al., 2010), though non-human mammals show favoritism toward genetic relatives (Silk, 2006, Smith, 2014). Many critics of kin selection's impact on human evolution suggest that culture is the more prominent force. Indeed, one of the most potent aspects of normative kinship is in its ability to structure routes of reciprocity and resource allocation in human societies by blurring lines of blood and marriage to unite and divide particular classes of relatives independently from genetics. In that case, cultural phenomena like kinship norms and kinship terminology may be the more important factor in shaping human behavior.

It is tempting to see kinship norms act as a bridge genetic relatedness and cultural convention, but it remains unclear whether any kinship norm or terminological system correctly and consistently identifies kin by degree of genetic relatedness (Morgan, 1870, Stone, 2014). Further, fictive kinship – the use of kin terms to designate others who are genetically unrelated, such as brothers in Christ or brothers in arms – can co-opt the psychology of cooperating with relatives and apply it to unrelated others (Carsten, 1995, Carsten, 2000, Clarke, 2008, Schneider, 1984). Kinship systems, especially in smaller-scale societies throughout the Pacific, often encompass relationships beyond genetic similarities (Sahlins, 2013, Sahlins, 1976). Though these Pacific societies' kinship systems often include terminology that does not directly convey genetic relatedness, favoritism toward more closely genetically related children over adopted children shows that these kinship systems do not totally override genetic favoritism (Silk, 1980). Therefore, the interplay between kin psychology directed toward genetic relatives and normative kinship is an interesting topic for investigation.

We recruited villagers in Yasawa, Fiji, to investigate how members of a small-scale society balance genealogical kin relations against kinship norms. We predict that, if Yasawans preferentially cooperate with genetic relatives, then they will make more generous choices for more closely genetically related others in an economic game. However, there is more to social life than generosity. We also predict that the extra norm structure of kinship facilitates coordination on either symmetric or asymmetric payouts that present a conflict of interest between players.

We first briefly describe how Yasawan kinship blurs consanguine and afinal lines that allow us to examine how genealogy and kinship interrelate to influence social decisions. In study 1, we quantitatively map out the insider, emic norms around Yasawan kinship terms through a card sort task. In study 2, we describe an economic game Yasawans played with kin. We analyze game results for both individual players and pairs of players. We investigate what factors promote more generous choices toward partners; kin altruism should promote more generous choices for closer genealogical relatives. We also examine what factors facilitate coordination on symmetric or asymmetric payouts when players' self-interests conflict.

Yasawa Island is the northern most in the Yasawa Island Chain, a cluster of volcanic islands in northwestern Fiji. Most Yasawans subsist as fisher–horticulturalists, relying on traditional food production techniques, local ecological conditions, and cooperative sharing. Yasawans organize their cooperative activities around traditional kin-based social hierarchy, which confers certain obligations, responsibilities, and privileges based upon relative rank.

Traditional Fijian village life centers around a highly-structured, clan-based kinship system, culminating in a hereditary chief. Maintaining one's place within this hierarchy through proper observance of kin obligations is central to the definition of being a good Fijian (Brison, 2001). Properly observing traditional norms is also often believed to provide supernatural protection from local spirits and sorcery (Brison, 2001, Katz, 1999, McNamara et al., 2014, Tomlinson, 2004). Even the hereditary chiefs can be ousted from power if they are seen to fail in their duties to the community (Gervais, 2013).

Traditional indigenous Fijian resource exchange is marked by three principles: communal ownership among members of a given kin group, top-down decision-making, and the kerekere system for soliciting aid from kin. Within a village or kin group, the highest-ranking individuals are responsible for instigating and directing group action. Namely, the chiefs decide how resources and labor will be arranged within the village, elders have the next say, then the eldest male of each household, etc. Those who are lower in status must not exhibit too much ambition so as to supersede their place, while those who are higher in authority are obliged to look out for the wellbeing of those who are below (Sahlins, 1962, Schlossberg, 1998, Torren, 1990).

The kerekere (“please”) system can be seen as a mechanism for resource redistribution within this hierarchical-decision making and communal ownership setting. Kerekere can be used to make requests for food, service, use of property, money, etc. Importantly, a kerekere request should ideally only be directed toward kin. Kerekere fits hand-in-glove with the ideal of community ownership, as it is a great shame to have to make a kerekere request outside of the family and to reject a kerekere request from a person who is genuinely in need. Kerekere may act as an informal insurance system that helps distribute resources from those with many resources to those with few. When one chooses to fulfill a kerekere request, this fulfillment comes with the expectation that it can be reciprocally called upon for aid in the future (though the scale need not be exactly equivalent; the relationship is often more important than items exchanged; Farrelly and Vudiniabola, 2013, Sahlins, 1962, Schlossberg, 1998, Thomas, 1992).

This traditional exchange system embedded within hierarchical decision-making and communal ownership adds an illuminating dimension to the present study. Kerekere in particular is controversial in modern Fiji because it is quite antithetical to individual accumulation of capital necessary for western-style economic development. Kerekere is often cited as a major hurdle to small business growth, deemed detrimental to entrepreneurial spirit in indigenous Fijian villages, and blamed for a dependency orientation in indigenous Fijian culture (Farrelly & Vudiniabola, 2013). Further, traditional deference to authority may reduce the effectiveness of initiatives that require egalitarian community engagement (Schlossberg, 1998). As such, individuals' self-maximizing motivations may be mitigated by both the inclusive-fitness tracking motivations to distribute resources to genetic relatives and – particularly in the presence of this kin-mediated hierarchical exchange system – may be re-directed against individual self-interest to benefit the communal interests of the family based upon norms of how to interact with particular kin. Importantly, evidence that Yasawans might be using these relationship cues to act differently toward particular relatives may further highlight how cooperation systems may operate outside of the context of individualist orientation and third-party monitoring systems inherent to modern western economic and governmental systems.

The Yasawan kinship system,1 broadly similar to kinship throughout Fiji, is patrilocal and bifurcate merging patrilineal (Capell and Lester, 1945a, Capell and Lester, 1945b, Capell and Lester, 1946a, Capell and Lester, 1946b, Morgan, 1870, Nayacakalou, 1955, Nayacakalou, 1957). Hierarchy within the traditional political system is organized along the distinction between male and female (with men out-ranking women) and age (with older out-ranking younger). The Yasawan kinship system, like kinship elsewhere in Fiji, comprises several primary units that track increasing distance beyond the immediate family: itokatoka (extended family or sub-clan), mataqoli (clan, several itokatoka linked by a common male ancestor, act as land-owning units), and yavusa (phratry, a cluster of mataqoli linked by a common male ancestor). The archetypal yavusa is sub-divided into five mataqoli clans, each descending from one of five founding brothers who were the sons of the local ancestor spirit Kalou-vu; the chiefly clan comes from the eldest brother's line. Traditional village affairs like gardening, fishing, building houses, etc. are often organized around yavusa and mataqoli bonds. Though the clans forming each yavusa are intimately tied to the land where their founders established their lineages, mataqoli and yavusa can span multiple villages, and some villages include multiple yavusa (France, 1969, Nayacakalou, 1955, Nayacakalou, 1957).

This intimate connection between place and people makes one's place/family background an important part Fijian identity (Brison, 2001). The Fijian kinship system includes terms that track individuals' origins according to both their father's and mother's lineages (Felgentreff, 1999). Taukei (native, technically “owner”) refers to a person who belongs in and to a particular place. Koi tracks father's village (koi is followed by a place name – a person whose father is from a particular village), and vasu tracks mother's village (vasu also connotes privileges to take freely from one's mother's relatives). Origin is so fundamental to identity that Yasawans who are born in the city and who have never even been to the village will still call themselves e.g. koi Teci (if their father was from Teci village).

Yasawan kin terms within the immediate family (Fig. 1) assign various kin labels based upon sex and seniority. Following the bifurcate merging logic, some terms combine consanguine and affinal relations together in parallel/classificatory vs. cross designations. The parallel vs. cross designations are determined by relationship to one's parents. Kin terms for mother (nau) and father (tata) are applied to parents, parents' same-sex siblings, and parent's same sex siblings' spouses (e.g., mother's sister's husband is tata). Conversely, parents' opposite-sex siblings are cross, thus avuncular (gwadi is both “mother's brother/uncle,” and “father's sister/aunt”). Similarly, the same tamaya “brother” and tinaya “sister” sibling terms are used for full siblings and for children of a parents' same sex siblings, while children of parents' opposite sex siblings are cross-cousins (tavale). Importantly, classificatory sibling cousins and cross-cousins are equally genealogically related to the ego, but the norms for how to interact with them differ drastically. Cross-cousins are often ideal marriage partners, are friends who are easy to joke with, and are generally treated more informally. However, classificatory siblings are treated with the utmost respect and avoided for marriage even more strictly than full siblings. For example, conversation between a woman and her classificatory brother is strictly prohibited, and the two must always be chaperoned. Classificatory siblingship can extend to even distant cousins who are practically genetically unrelated.

Section snippets

Study 1: Yasawan kinship norms

In study 1, we examine Yasawan kinship norms to investigate how kin terms compare to each other within the Yasawan kinship system. We later use these kinship norms to compare the effects of culturally defined, linguistic terms against genealogical relatedness in study 2.

Study 2: kin coordination game

In study 2, we investigate how genealogical relatedness and kinship norms influence Yasawans' social decisions. Participants played an economic game with a series of known others in the village, identified solely through photographs (without name or kinship label). Economic games have been used to measure prosocial norms and preferences in cultures around the world and within this population (Engel, 2011, Gervais, 2013, Gurven, 2004b, Henrich, 2006, Henrich, 2012, Henrich and Henrich, 2014,

General discussion

We use a card sort task and principle component analysis to extract two dimensions – respect/closeness and joking/authority – that describe Yasawan kinship norms. We use a three-choice, battle of the sexes-style economic game to investigate how Yasawans balance genealogical relatedness against kinship norms when forced to choose between self-interested, egalitarian, or generous options. This conflict between self and other-interest recapitulates the balance of obedience and interdependence

Supplementary materials

The following is the supplementary data to this article.

Supplementary material 1

Supplementary material 2

Acknowledgments

This research was conducted through funding from the University of British Columbia Psychology Department, with additional funding from the UBC Cultural Evolution of Religion Research Consortium and Human Evolution, Cognition, and Culture groups. These groups are able to provide this funding as part of a Canadian Social Sciences and Humanities Research Council grant. We would like to thank our Fijian research team, especially Paula Tekei, for their tireless work in making this research

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