High-fidelity copying is not necessarily the key to cumulative cultural evolution: a study in monkeys and children.

The unique cumulative nature of human culture has often been explained by high-fidelity copying mechanisms found only in human social learning. However, transmission chain experiments in human and non-human primates suggest that cumulative cultural evolution (CCE) might not necessarily depend on high-fidelity copying after all. In this study, we test whether defining properties of CCE can emerge in a non-copying task. We performed transmission chain experiments in Guinea baboons and human children where individuals observed and produced visual patterns composed of four squares on touchscreen devices. In order to be rewarded, participants had to avoid touching squares that were touched by a previous participant. In other words, they were rewarded for innovation rather than copying. Results nevertheless exhibited fundamental properties of CCE: an increase over generations in task performance and the emergence of systematic structure. However, these properties arose from different mechanisms across species: children, unlike baboons, converged in behaviour over generations by copying specific patterns in a different location, thus introducing alternative copying mechanisms into the non-copying task. In children, prior biases towards specific shapes led to convergence in behaviour across chains, while baboon chains showed signs of lineage specificity. We conclude that CCE can result from mechanisms with varying degrees of fidelity in transmission and thus that high-fidelity copying is not necessarily the key to CCE.

More or Less Unnatural: Semantic Similarity Shapes the Learnability and Cross-Linguistic Distribution of Unnatural Syncretism in Morphological Paradigms.

Morphological systems often reuse the same forms in different functions, creating what is known as syncretism. While syncretism varies greatly, certain cross-linguistic tendencies are apparent. Patterns where all syncretic forms share a morphological feature value (e.g., first person, or plural number) are most common cross-linguistically, and this preference is mirrored in results from learning experiments. While this suggests a general bias towards natural (featurally homogeneous) over unnatural (featurally heterogeneous) patterns, little is yet known about gradients in learnability and distributions of different kinds of unnatural patterns. In this paper we assess apparent cross-linguistic asymmetries between different types of unnatural patterns in person-number verbal agreement paradigms and test their learnability in an artificial language learning experiment. We find that the cross-linguistic recurrence of unnatural patterns of syncretism in person-number paradigms is proportional to the amount of shared feature values (i.e., semantic similarity) amongst the syncretic forms. Our experimental results further suggest that the learnability of syncretic patterns also mirrors the paradigm's degree of feature-value similarity. We propose that this gradient in learnability reflects a general bias towards similarity-based structure in morphological learning, which previous literature has shown to play a crucial role in word learning as well as in category and concept learning more generally. Rather than a dichotomous natural/unnatural distinction, our results thus support a more nuanced view of (un)naturalness in morphological paradigms and suggest that a preference for similarity-based structure during language learning might shape the worldwide transmission and typological distribution of patterns of syncretism.

Probability matching is not the default decision making strategy in human and non-human primates.

Probability matching has long been taken as a prime example of irrational behaviour in human decision making; however, its nature and uniqueness in the animal world is still much debated. In this paper we report a set of four preregistered experiments testing adult humans and Guinea baboons on matched probability learning tasks, manipulating task complexity (binary or ternary prediction tasks) and reinforcement procedures (with and without corrective feedback). Our findings suggest that probability matching behaviour within primate species is restricted to humans and the simplest possible binary prediction tasks; utility-maximising is seen in more complex tasks for humans as pattern-search becomes more effortful, and we observe it across the board in baboons, altogether suggesting that it is a cognitively less demanding strategy. These results provide further evidence that neither human nor non-human primates default to probability matching; however, unlike other primates, adult humans probability match when the cost of pattern search is low.

Category Clustering and Morphological Learning.

Inflectional affixes expressing the same grammatical category (e.g., subject agreement) tend to appear in the same morphological position in the word. We hypothesize that this cross-linguistic tendency toward category clustering is at least partly the result of a learning bias, which facilitates the transmission of morphology from one generation to the next if each inflectional category has a consistent morphological position. We test this in an online artificial language experiment, teaching adult English speakers a miniature language consisting of noun stems representing shapes and suffixes representing the color and number features of each shape. In one experimental condition, each suffix category has a fixed position, with color in the first position and number in the second position. In a second condition, each specific combination of suffixes has a fixed order, but some combinations have color in the first position, and some have number in the first position. In a third condition, suffixes are randomly ordered on each presentation. While the language in the first condition is consistent with the category clustering principle, those in the other conditions are not. Our results indicate that category clustering of inflectional affixes facilitates morphological learning, at least in adult English speakers. Moreover, we found that languages that violate category clustering but still follow fixed affix ordering patterns are more learnable than languages with random ordering. Altogether, our results provide evidence for individual biases toward category clustering; we suggest that this bias may play a causal role in shaping the typological regularities in affix order we find in natural language.

Evaluación de los factores motivacionales en la práctica del Pole Sport: validación preliminar / Evaluation of motivational factors in the practice of Pole Sport: preliminary validation

El presente trabajo se propone dar respuesta a los principales motivos que llevan a los deportistas a practicar Pole Sport con el objetivo de mejorar la gestión de los centros deportivos donde se practica el mismo. Se utilizó como herramienta la Escala de Medida de los Motivos para la Actividad Física-Revisada (MPAM-R) de Celis-Merchán (2006), que mide los motivos de práctica deportiva en cinco dimensiones y consta de 30 ítems (Likert 1 al 7). Mediante la plataforma on-line Survio se difundió el cuestionario a los participantes procedentes de una academia que opera a nivel regional en la Comunidad de Andalucía, obteniéndose respuesta de 85 usuarios de los que 80 fueron mujeres y 5 hombres. Se empleó el software estadístico SPSS 22.0 para el análisis descriptivo de los datos, el análisis factorial exploratorio y de fiabilidad. Los resultados obtenidos mostraron que el «disfrute» es el principal factor motivacional para la práctica de Pole Sport, obteniendo una pertinencia adecuada del análisis factorial, así como una estructura claramente definida (AU)

The present work aims to respond to the main reasons that lead athletes to Pole Sport practice with the objective of improving the management of sports centers where it is practiced. In order to respond to the research problem, the Scale of Measurement of Reasons for Physical Activity-Revised (MPAM-R) by Celis-Merchán (2006) was used. This scale has 30 items (Likert 1 to 7) and measures the reasons of sports practice in five dimensions. Through the Survio online software, the questionnaire was distributed to 85 athletes, of whom 80 were women and five men. For the descriptive analysis of the data, exploratory factorial, and reliability, the statistical program SPSS 22.0 was used. The results obtained showed that the «enjoyment» was the main motivational factor for the practice of Pole Sport, which agree with the results obtained by Frederick and Schuster (2003) (AU)

Estudio de las proteínas solubles liberadas espontáneamente por el parásito Plasmodium falciparum (exoproteínas) / Study of the soluble proteins spontaneously liberated by the parasite Plasmodium falciparum

Cultivos de Plasmodium falciparum, cepa FCB1 parcialmente sincronizados con sorbitol al 5 por ciento, fueron sometidos a marcación metabólica con superíndice 35 S-metionina o con üH-isoleucina, durante todo el desarrollo intraeritrocítico. La liberación de proteínas solubles o exoproteinas marcadas con superíndice 35 S- metionina al medio de cultivo fué baja durante el desarrollo de anillos y trofozoitos maduros, aumentó durante la esquizogonia y fué máxima en el proceso de disrupción de las células rojas infectadas con esquizontes y en la reinvasión de los merozoítos. Las exoproteínas fueron obtenidas de células rojas infectadas con esquizontes, concentradas por un gradiente isopícnico de Percoll (96), en ausencia de suero, con el objeto de evitar la inteferencia de los componentes del suero, para su posterior análisis. Las exoproteínas liberadas por el parásito presentan patrones electroforéticos (SDS-PAGE) diferentes, si son obtenidas en presencia o en ausencia de eritrocitos. Se identificaron aproximadamente 35 polipétidos de Mr entre 200.000 y 19.000. Tres polipéptidos de Mr 77.000, 48.000 y 36.000 están presentes en el sobrenadante del cultivo cuando el merozoíto invade nuevos eritrocitos. Estas proteínas podrían estar asociadas a la cubierta celular del merozoíto, ya que se ha demostrado por microscopía electrónica que esta es dejada por el parásito cuando invade (20,21). Estas exoproteínas están ausentes en el medio de cultivo cuando el merozoíto no invade. Cuatro polipéptidos de Mr 153.000, 86.000, 65.800 y 65.000 fueron identificados solo cuando las exoproteínas fueron obtenidas en ausencia de eritrocitos (no ocurre invasión) y están ausentes en exoproteínas obtenidas en presencia de eritrocitos. Esto parece sugerir que se adhiere al eritrocito y se pierde en el proceso de invasión. Incubando exoproteínas obtenidas en ausencia de eritrocitos con eritrocitos no infectados a concentraciones de 0.5 x 10 superíndice 6 células rojas/ml se observó la desaparición de bandas del patrón electroforético (SDS-PAGE) de Mr 153.000, 139.000, 136.000, 86.000 y 65.000 con respecto al patrón en ausencia de eritrocitos, confirmando nuevamente aquellas proteínas que se pierden en el proceso de invasión. Aún no se ha demostrado la especificidad de la unión de estas proteínas por la membrana del eritrocito. Por medio de inmunoprecipitaciones de las exoproteínas con sueros de pacientes parcialmente...