Varikin Findings: There are no universals in the cultural evolution of kinship terminology

There is huge potential for variation between kinship terminology (systems of words for relatives) cross-culturally. In fact, for a set of 16 relatives, there are 10,480,142,147 theoretically possible ways to categorise them. Given the potential for effectively unbridled variation in kinship terminology, observed diversity seems remarkably constrained, and has previously been categorised into six key types (see Fig. 1). Each type has been hypothesised to align with particular cultural norms of descent, marriage or residence patterns, and it was thought that these social systems acted as drivers of the variation and change of kinship terminology. However, since these conclusions were reached, there have been significant improvements in data and statistics. Will they still stand up when tested using more modern methods?

VariKin members Sam Passmore and Fiona Jordan’s 2020 publication No universals in the cultural evolution of kinship terminology put this to the test. They used phylogenetic comparative methods (PCMs) to explore the cultural evolutionary patterns of kinship terminology diversity, particularly testing so-called drivers of change such as marriage, residence and descent. This study marks the first cross-language-family phylogenetic analysis of the drivers of kinship terminology and investigates the Austronesian, Bantu and Uto-Aztecan language families (selected due to their large size and cultural data availability). In the study, they found no evidence for previously assumed universal drivers of evolution in kinship terminologies, because no presumed universal relationship linking kinship terminology and social structure was supported across all language families. This is not because one or two societies do not follow a trend: for most of the hypotheses tested, they could not conservatively even claim ‘statistical regularity’.

However, rather than assume that the lack of statistical relationship between kinship terminology types and social structure indicates no functional relationship, the authors suggest that the typology might misrepresent kinship terminological diversity by being too crude a characterisation. This raises the important question of how well existing typologies represent known diversity, and the results from this particular study – which was always an integral investigation of the VariKin Project – have helped to clear the ground for more detailed characterisations of kinship organisation in future. For example, as stated in the publication, the creation of the “Kinbank” database as part of the VariKin project will allow us to more realistically characterise types and patterns of change in kinterms without built-in assumptions of the influence from social structure.

Varikin Findings: How Pama-Nyungan Grandparent Naming Systems Change

The VariKin project has examined the cultural evolution of kinship terminology from a range of perspectives and methods. Considerable research by our group and others has focused on the comparison of cousin and sibling terms, but grandparent terms, the topic of this paper, are largely understudied. The social salience of grandparents, due to their frequent role in the care of grandchildren as well as in controlling wealth and cultural knowledge, suggested that a project of this focus was long overdue.

Catherine Sheard and Fiona Jordan from the VariKin team, along with Claire Bowern and Rikker Dockum (Yale University), addressed this gap in an open access paper published earlier this year in Evolutionary Human Sciences. “Pama–Nyungan grandparent systems change with grandchildren, but not cross-cousin terms or social norms” compares grandparent terms across 134 Australian languages from the Pama-Nyungan family. Using Pama-Nyungan as a study system is less common in studies of kinship macroevolution. Australia’s ecological and anthropological history (namely, a continental radiation of primarily hunter-gatherer languages) provides a contrasting example to language families associated with agricultural spreads, such as Austronesian or Bantu.

 

 

A standard way of thinking about grandparental kin terms is to consider each of parent of mother and father: MM, MF, FM, and FF. Pitjantjatjara has a two-term system that merges gender like English does, with ‘kami’ for MM and FM (grandmother), and ‘amu’ for FF and MF (grandfather). Other languages have four separate terms, for example, Alyawarra has ‘arrenge’ FF, ‘artartetye’ MF, ‘anyanye’ MM and ‘aperle’ FM. Pama-Nyungan languages also explore other three-term systems that merge parallel grandparents, so that MM=FF as in Djapu, or merge cross grandparents, so that MF=FM, as in Yagara.

The group used Bayesian phylogenetic comparative methods to model the stages of grandparent naming systems (see Fig 3. below). This analysis suggests that the ancestral, proto-Pama–Nyungan system had four separate terms (on the left of the diagram below). In different groups of languages, this shifted to either a two-term system (merging sexes, like English), or a three-term system merging parallel grandparents (MM=FF), with a potential third stage (merging cross, MF=FM) emerging in some cases from there. Note that some of these transitions seem to have occurred without a stable intermediate state.

 

 

As well as making discoveries regarding systems of grandparental terminology, Catherine and colleagues note that we still do not know why it is that these systems transitioned in that particular order. In their paper, the authors tested potential social factors that might drive these transitions (community marriage organisation, and post-marital residence) but found no significant correlations. There was minimal co-evolution with the rest of the terms in the kinship system, and it remains an open question what linguistic or social forces shape grandparent terms.

VariKin Findings: Frequently-used kinship terms evolve slowly

VariKin Findings: Frequently-used kinship terms evolve slowly

— by Maisie Ford

Language is constantly changing. As new words are born or enter a language, old words fall out of use. Linguists have known for a long time that some words endure longer than others. Some core vocabulary, like numbers, names of common animals/plants, and words for parts of the body can be thousands of years old and still in use. This intuition was put to the test by Mark Pagel, Quentin Atkinson, and Andrew Meade in their 2007 paper, Frequency of word-use predicts rates of lexical evolution throughout Indo-European history. Using language corpora (large collections of transcribed speech or collected text), and phylogenetic comparative methods, they found that more frequently used words from the core vocabulary are replaced at a slower rate in European languages.

Image credit: Altrincham Adventures in Art

But why is this? Do often-used words leave a stronger imprint in our minds and are therefore less likely to be lost? Or is it that large scale conceptual or social changes relating to how we think and talk about the world around us are more likely to displace words that are used less often?

VariKin team members Péter Rácz and Sam Passmore (lead authors), Catherine Sheard and Fiona Jordan explored this very question with kinship words in their open-access paper, “Usage frequency and lexical class determine the evolution of kinship terms in Indo-European”, published in Royal Society Open Science in October 2019.

Péter collected large-scale language corpora across 47 Indo-European languages, so as to determine the frequency of use of terms for family and kin. Using phylogenetic comparative methods, Sam modelled how fast kinship words are replaced in these languages. Kinship terms are not just single linguistic labels for individuals, because multiple relatives can be called by the same term such as “cousin” in English, or “tante” (aunt, in French). Kin terms form systems, and multiple terms shift together when one system is replaced with another one through social or cultural changes. VariKin team members explore this aspect in some of their other papers:

Image credit: Altrincham Adventures in Art

In the present paper, the team found that, as with core vocabulary, the most frequently used kinship terms are replaced more slowly over time. In fact, the relationship between rate of replacement and frequency of use was found to be even stronger in kinship terminology than in core vocabulary in general. This is hypothesised to be due to the fact that kinship words, in every language, constitute a closed lexical class, which suggests that the reason more frequent words are more resilient is not that they are more memorable. Rather it is that they are less likely to be affected by complex conceptual changes in language. Terms for ‘mother’ or ‘father’ last for thousands of years!

The findings shed further light on how language change is related to language use.  It also adds to what we know about the ways in which evolutionary parallels exist in biology and culture (we know that genes involved in multiple functions change more slowly), and informs debates on dynamics of change in linguistics and complex systems theory in general.

Watch this space for an interview coming soon with Péter Rácz and Sam Passmore in which we discuss this paper further. We will be posting these summaries of papers from the VariKin project over the next few months as the project winds up.