Variation in caregivers' references to their toddlers: child-directed speech in Vanuatu and Canada

Abstract The authors examined similarities and differences in Canadian and ni-Vanuatu caregivers' child-directed speech to their toddlers (N = 35, Mage: 21?months, 20 girls). Speech samples were collected (2013?2016) during free play and analyzed with a focus on describing parents' references to their toddlers. Canadian caregivers referred significantly more to toddlers' tangible characteristics (relative risk, RR = 2.12) and internal states (RR = 2.31), whereas ni-Vanuatu caregivers referred more to actions (RR = 2.04). When referring to internal states, Canadian mothers referred significantly more to mind-minded states, whereas ni-Vanuatu caregivers referred more to body-minded states (RR = 7.98). These findings are interpreted as capturing meaningful differences in toddlers' opportunities to attend to themselves. Implications for self-concept development are discussed

Breaking symmetry in liquid bridges: the effect of pinning and aspect ratio on capillary forces

Capillary bridges between solid substrates are critical to a myriad of natural and industrial processes, such as oil recovery from porous rocks, or the packaging of micro-circuitry components. Generally, the surfaces of these solids are not uniform, and contain physical or chemical heterogeneities that result in asymmetric bridge morphologies (due to the partial pinning of the solid-liquid-vapor interface). While such pinning can greatly affect the forces and morphologies of the liquid, many studies that investigate capillary bridges assume the solid surfaces to be ideal, and the subsequent bridge profiles to be highly symmetric. This thesis details our investigations of how breaking symmetry (through changing of the pinning condition or the shape of the substrates) results in quantitative changes to the properties of the capillary bridges such as the morphology, forces and torques. First, we explored the importance of the pinning condition by studying capillary bridges in a narrow rectangular slit pore, which is one of the simplest ways to break symmetry. We employed experiments, numerical simulations, and theory to highlight the importance of pinning on the bridge morphology and associated capillary forces. Experiments showed that as the height of the slit pore is increased past the width of the strip the mean curvature of the capillary bridge changes sign from negative to positive (concave to convex). This counterintuitive observation was confirmed by using Surface Evolver simulations. Interestingly, the force the capillary bridge exerts on the pore itself always remains attractive due to the dominance of the vertical projection of the surface tension force at the pinning boundary. It was also found that the mean curvature was independent of the liquid volume in the pore, as long as the bridge did not extend to the end of the strip. We developed a simple theory to show that the change in mean curvature can be described as a competition between the confinement of the liquid bridge and the wetting of the strip. Next, we studied the role of substrate shape on the restoring forces and torques of capillary based self-alignment systems, such as “flip-chip” micro-circuit packaging. To do this we varied systematically the aspect ratio of rectangular substrates under conditions where the fluid was pinned on all sides. We found that increasing the aspect ratio of the substrates (even when holding the substrate area, and liquid volume constant) resulted in higher total restoring forces and torques under both lateral and rotational perturbations. It is also shown that the rotational restoring force is of order the shift restoring force, and should generally be considered in alignment analysis. Finally, parameters from experimental flip-chip devices were used in our simulations to show how current capillary self-alignment schemes can benefit from using rectangular substrate shapes with aspect ratio greater than one

A combined PLC and CPU approach to multiprocessor control

A sophisticated multiprocessor control system has been developed for use in the E-Power Supply System Integrated Control (EPSSIC) on the DIII-D tokamak. EPSSIC provides control and interlocks for the ohmic heating coil power supply and its associated systems. Of particular interest is the architecture of this system: both a Programmable Logic Controller (PLC) and a Central Processor Unit (CPU) have been combined on a standard VME bus. The PLC and CPU input and output signals are routed through signal conditioning modules, which provide the necessary voltage and ground isolation. Additionally these modules adapt the signal levels to that of the VME I/O boards. One set of I/O signals is shared between the two processors. The resulting multiprocessor system provides a number of advantages: redundant operation for mission critical situations, flexible communications using conventional TCP/IP protocols, the simplicity of ladder logic programming for the majority of the control code, and an easily maintained and expandable non-proprietary system

Evidence for Proactive and Reactive Helping in Two- To Five-Year-Olds from A Small-Scale Society

Humans are unique in their propensity for helping. Not only do we help others in need by reacting to their requests, we also help proactively by assisting in the absence of a request. Proactive helping requires the actor to detect the need for help, recognize the intention of the other, and remedy the situation. Very little is known about the development of this social phenomenon beyond an urban, industrialized setting. We examined helping in nineteen two- to five-year old children in small-scale rural villages of Vanuatu. In the experimental condition, the intentions of the experimenter were made salient, whereas in the control condition they were ambiguous. Children helped more often in the experimental compared to the control condition, suggesting that the propensity to monitor others’ goals and act accordingly can be detected in different cultural contexts

A digital long pulse integrator

A prototype digital integrator with very long integration capabilities has been developed and field tested on an inductive magnetic sensor on the DIII-D Tokamak. The integrator is being developed for use on ITER with a pulse length of 1000 s, and has direct applications for other long pulse Tokamaks. Inductive magnetic sensors are routinely used on existing Tokamaks, are well understood, and are extremely robust, however, they require integration of the signal to determine the magnetic field strength. The next generation of Tokamaks, will have pulse lengths of 1000 s or longer, require integrators with drift and noise characteristics compatible with the very long pulse lengths. This paper will discuss the architecture, algorithms, and programming of the Long Pulse Integrator (LPI). Of particular interest are the noise control and the built-in offset correction techniques used in this application

Jove i participatiu : requisits del nou model de transmissió cultural

La imitació com a mètode d'aprenentatge humà mai ha estat un procés simple. L'evolució cultural de l'espècie humana que d'ella es deriva segueix arrelada a una actitud selectiva -els models escollits es caracteritzen per ser individus amb prestigi-, però sembla ser que aquesta reputació ja no recau en els mateixos de sempre. Mitjançant un estudi de camp amb els Tsimane' -un grup ètnic bolivià-, s'ha vist que el lideratge ha passat a mans dels més joves, tenint aquests un alt nivell educatiu i una forta vinculació amb el treball comunitari.La imitación como método de aprendizaje humano nunca ha sido un proceso simple. La evolución cultural de la especie humana que de ella se deriva sigue arraigada a una actitud selectiva -los modelos escogidos se caracterizan por ser individuos con prestigio-, pero parece ser que esa reputación ya no recae en los mismos de siempre. Mediante un estudio de campo con los Tsimane -un grupo étnico boliviano-, se ha visto que el liderazgo ha pasado a manos de los más jóvenes, teniendo éstos un alto nivel educativo y una fuerte vinculación con el trabajo comunitario.Imitation as a method of human learning has never been a simple process. The cultural evolution of the human species based on this method continues to be established in a selective attitude - the selected models are characterized for being prestigious individuals. However, it seems to be that this prestige is no longer conferred to the same models as before. A field study with the Tsimane' - an ethnic group in Bolivia-, has demonstrated that the leadership has moved to the hands of the youngest, who have a high educational level and strong links with community work

Bayaka adolescent boys nominate accessible adult men as preferred spear hunting = models les adolescents bayaka nomment les hommes adultes qui leurs sont accessibles comme modèles préférés pour l’apprentissage de la chasse à la lance

Data availability: data are available on request. The code used in the analysis can be found online at https://www.journals.uchicago.edu/doi/suppl/10.1086/716853/suppl_file/303893code.zip .Online enhancements: appendix, R code.Humans are selective social learners. In a cultural landscape with many potential models, learners must balance the cost associated with learning from successful models with learning from accessible ones. Using structured interviews, we investigate the model selection biases of Congolese BaYaka adolescent boys learning to hunt with spears (n = 24; mean age [mage] = 15.79 years; range, 12–20 years). Results from social relations models suggest that adolescents nominated accessible adult men (closely related kin and neighbors) as preferred spear hunting models. Direct cues for success were not strong predictors for adolescent nomination in the statistical models, despite learners justifying model selection according to teaching and spear hunting skill. Indirect cues including body mass index, age, and cross-domain prestige were weak predictors for adolescent nomination. We interpret these findings as suggesting that BaYaka spear hunting knowledge is widely shared in the community, with all adult men participating in spear hunting and therefore having the requisite experience to transmit this skill. This supports previous findings that in egalitarian societies with low rates of role specialization, prestige has limited importance for cross-domain learning. Les êtres humains sont des apprenants sociaux sélectifs. Dans un paysage culturel comportant de nombreux modèles potentiels, les apprenants doivent trouver un équilibre entre le coût associé à l’apprentissage à partir de modèles qui ont fait leurs preuves et celui à partir de modèles accessibles. À l’aide d’entretiens structurés, nous étudions les biais de sélection de modèles des adolescents congolais BaYaka qui apprennent à chasser à la lance (n = 24, âge moyen = 15,79 ans, intervalle: 12–20 ans). Les résultats des modèles de relations sociales suggèrent que les adolescents désignent des hommes adultes accessibles (parents proches et voisins) comme modèles préférés de chasse à la lance. Les indices directs de réussite ne constituaient pas des prédicteurs forts de nomination par des adolescents dans les modèles statistiques, bien que les apprenants justifiaient la sélection du modèle en fonction des habiletés d’enseignement et de la chasse à la lance. Les indices indirects, dont l’indice de masse corporelle, l’âge et le prestige inter-domaines, constituaient de faibles prédicteurs de la nomination par les adolescents. Ces résultats suggèrent que la connaissance de la chasse à la lance des BaYaka est largement partagée dans la communauté, puisque tous les hommes adultes participent à la chasse à la lance et ont donc l’expérience requise pour transmettre cette compétence. Ceci confirme les résultats de recherches antérieures selon lesquels dans les sociétés égalitaires, qui ont de faibles niveaux de spécialisation des rôles, le prestige a une importance limitée dans l’apprentissage inter-domaines.Funding for this research was provided by awards from the Wenner-Gren Foundation (no. 9789) and the Leakey Foundation to S. Lew-Levy and A. Milks. Research was also supported by a Social Sciences and Humanities Research Council of Canada Postdoctoral Fellowship (no. 756-2019-0102) to S. Lew-Levy

Sleep Timing and Duration in Indigenous Villages with and Without Electric Lighting on Tanna Island, Vanuatu

It has been hypothesized that sleep in the industrialized world is in chronic deficit, due in part to evening light exposure, which delays sleep onset and truncates sleep depending on morning work or school schedules. If so, societies without electricity may sleep longer. However, recent studies of hunter-gatherers and pastoralists living traditional lifestyles without electricity report short sleep compared to industrialized population norms. To further explore the impact of lifestyles and electrification on sleep, we measured sleep by actigraphy in indigenous Melanesians on Tanna Island, Vanuatu, who live traditional subsistence horticultural lifestyles, in villages either with or without access to electricity. Sleep duration was long and efficiency low in both groups, compared to averages from actigraphy studies of industrialized populations. In villages with electricity, light exposure after sunset was increased, sleep onset was delayed, and nocturnal sleep duration was reduced. These effects were driven primarily by breastfeeding mothers living with electric lighting. Relatively long sleep on Tanna may reflect advantages of an environment in which food access is reliable, climate benign, and predators and significant social conflict absent. Despite exposure to outdoor light throughout the day, an effect of artificial evening light was nonetheless detectable on sleep timing and duration

Out of the empirical box: A mixed-methods study of tool innovation among Congolese BaYaka forager and Bondongo fisher–farmer children

© 2021 The Authors. Tool innovation has played a crucial role in human adaptation. Yet, this capacity seems to arise late in development. Before 8 years of age, many children struggle to solve the hook task, a common measure of tool innovation that requires modification of a straight pipe cleaner into a hook to extract a prize. Whether these findings are generalizable beyond postindustrialized Western children remains unclear. In many small-scale subsistence societies, children engage in daily tool use and modification, experiences that theoretically could enhance innovative capabilities. Although two previous studies found no differences in innovative ability between children from Western and small-scale subsistence societies, these did not account for the latter’s inexperience with pipe cleaners. Thus, the current study investigated how familiarity with pipe cleaners affected hook task success in 132 Congolese BaYaka foragers (57 girls) and 59 Bondongo fisher–farmers (23 girls) aged 4–12 years. We contextualized these findings within children’s interview responses and naturalistic observations of how pipe cleaners were incorporated into daily activities. Counter to our expectation, prior exposure did not improve children’s performance during the hook task. Bondongo children innovated significantly more hooks than BaYaka children, possibly because they participate in hook-and-line fishing. Observations and interviews showed that children imagined and innovated novel uses for pipe cleaners outside the experimental context, including headbands, bracelets, and suspenders. We relate our findings to ongoing debates regarding systematic versus unsystematic tool innovation, the importance of prior experience for the ontogeny of tool innovation, and the external validity of experimental paradigms

A hybrid digital-analog long pulse integrator

A digital-analog integrator has been developed for use with inductive magnetic sensors in long-pulse tokamaks. Continuous compensation of input offsets is accomplished by alternating analog-to-digital convertor samples from the sensor and a dummy load, while an RC network provides passive integration between samples. Typically a sampling rate of 10 kHz is used. In operational tests on the DIII-D tokamak, digital and analog integration of tokamak data show good agreement. The output drift error during a 1200 s integration interval corresponds to a few percent of the anticipated signal for poloidal field probes in International Thermonuclear Experimental Reactor (ITER), and bench tests suggest that the error can be reduced further