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Kinship, heritage, and ethnic choice : ethnolinguistic registration across four generations in contemporary Finland


We studied how individuals’ ethnolinguistic affiliation relates to the ethnolinguistic structure of kinship in contemporary Finland, a society in which Finnish-speaking and Swedish-speaking ethnolinguistic groups have coexisted for centuries and mixed marital unions are common. Using multigenerational data from the population register, we determined how the ethnolinguistic registration of children born in 1990–2015 relates to three generations of ancestors. We created a family tree that links children to their parents, four grandparents and eight great grandparents. Our intention was to both map the ethnolinguistic background of young people and predict a child’s affiliation based on their ancestry. The data revealed that ethnolinguistic affiliation is a more fluid and complex feature than expected when assessed only through child and parental characteristics. We found substantial diversity in ethnolinguistic background within the Swedish-speaking minority group, while most individuals in the Finnish-speaking majority group had a uniform background. We identified three types of bias in the ethnolinguistic affiliation of mixed-origin children: a matrilineal bias, a kinship majority bias and a Swedish ethnic minority bias. The analyses advanced our understanding of how the size of minority groups can shrink even when most couples in mixed unions favour minority group affiliation for their children.

A test of memory for stimulus sequences in great apes


Identifying cognitive capacities underlying the human evolutionary transition is challenging, and many hypotheses exist for what makes humans capable of, for example, producing and understanding language, preparing meals, and having culture on a grand scale. Instead of describing processes whereby information is processed, recent studies have suggested that there are key differences between humans and other animals in how information is recognized and remembered. Such constraints may act as a bottleneck for subsequent information processing and behavior, proving important for understanding differences between humans and other animals. We briefly discuss different sequential aspects of cognition and behavior and the importance of distinguishing between simultaneous and sequential input, and conclude that explicit tests on non-human great apes have been lacking. Here, we test the memory for stimulus sequences-hypothesis by carrying out three tests on bonobos and one test on humans. Our results show that bonobos’ general working memory decays rapidly and that they fail to learn the difference between the order of two stimuli even after more than 2,000 trials, corroborating earlier findings in other animals. However, as expected, humans solve the same sequence discrimination almost immediately. The explicit test on whether bonobos represent stimulus sequences as an unstructured collection of memory traces was not informative as no differences were found between responses to the different probe tests. However, overall, this first empirical study of sequence discrimination on non-human great apes supports the idea that non-human animals, including the closest relatives to humans, lack a memory for stimulus sequences. This may be an ability that sets humans apart from other animals and could be one reason behind the origin of human culture.

Sequence representation as an early step in the evolution of language


Human language is unique in its compositional, open-ended, and sequential form, and its evolution is often solely explained by advantages of communication. However, it has proven challenging to identify an evolutionary trajectory from a world without language to a world with language, especially while at the same time explaining why such an advantageous phenomenon has not evolved in other animals. Decoding sequential information is necessary for language, making domain-general sequence representation a tentative basic requirement for the evolution of language and other uniquely human phenomena. Here, using formal evolutionary analyses of the utility of sequence representation we show that sequence representation is exceedingly costly and that current memory systems found in animals may prevent abilities necessary for language to emerge. For sequence representation to evolve, flexibility allowing for ignoring irrelevant information is necessary. Furthermore, an abundance of useful sequential information and extensive learning opportunities are required, two conditions that were likely fulfilled early in human evolution. Our results provide a novel, logically plausible trajectory for the evolution of uniquely human cognition and language, and support the hypothesis that human culture is rooted in sequential representational and processing abilities.

The Maderö wreck : a ship loaded with bricks from Lübeck sunk in the Stockholm Archipelago in the late 15th century


The Maderö wreck was discovered in the 1960s in the Stockholm Archipelago, Sweden. An archaeological investigation undertaken in 2022 included the inspection and documentation of visible ship parts, sampling for dendrochronological analysis and sampling for ICP analysis from the brick cargo. The results show that the wood originates from the Baltic Sea area and was felled after 1467, while the clay for the brick originates from the Mecklenburg-Vorpommern area. The ship's technical analysis shows that it is a large clinker-built merchant ship. Traces of iron on a recovered stone shot indicate that the ship was armed when it sank.

The Inequality of Lifetime Pensions


At older ages, most people are supported by pension systems that provide payments based on prior contributions. An important, but neglected, aspect of inequality in how much people receive in pensions is the number of years they live to receive their pension. We examine inequality in lifetime-accumulated pensions and show the importance of mortality for understanding inequalities in pension payments, and contrast it to inequalities in working-age earnings and yearly pension payments among older adults. In contrast to most previous research on old-age inequality comparing different social groups, we focused on total-population-level inequality. Using Swedish register data covering the retired population born from 1918-1939, we found that lifetime pensions are much more unequal than pre-retirement earnings and yearly pensions. Our findings also show that mortality explains more than 50 percent of the inequality of lifetime pensions within cohorts, and plays an important role in explaining changes in inequality across cohorts (192 percent among men and 44 percent among women). Pension policies can affect lifetime pension inequality, but such effects are limited in magnitude unless they directly affect the number of years of receiving pensions.

How associations become behavior


The Rescorla and Wagner (1972) model is the first mathematical theory to explain associative learning in the presence of multiple stimuli. Its main theoretical construct is that of associative strength, but this is connected to behavior only loosely. We propose a model in which behavior is described by a collection of Poisson processes, each with a rate proportional to an associative strength. The model predicts that the time between behaviors follows an exponential or hypoexponential distribution. This prediction is supported by two data sets on autoshaped and instrumental behavior in rats.

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