Quasi-experimental research in culture sensitive psychology

The research presented in this article follows up on several aspects of Gustav Jahoda’s long and fruitful career: (1) his early fieldwork on cognitive development in Africa, particularly in the area of spatial skills; (2) his interest in cross-cultural psychology as a research method; and (3) his insistence on bringing anthropology and psychology together. The topic of our research is the development of a so-called “geocentric” frame of spatial reference. This is a cognitive style, in which individuals describe and represent small-scale table-top space in terms of large-scale geographic dimensions. We explore the development with age of geocentric language and cognition, and the relationships between the two. We also explore the many environmental and socio-cultural variables that favor the use of this frame. We demonstrate how we untangled several of these variables by using a succession of within-society group comparisons, in several societies where a geocentric frame is in common usage (Bali, Indonesia, India, and Nepal). Our research program unfolds like a detective story, where one finding that is difficult to interpret because of several confounded variables leads to another quasi-experimental group comparison that suggests another hypothesis, which is then tested in a further session of field-work. In each case, we emphasize how important it was to have extensive linguistic and ethnographic knowledge before implementing psychological tests. The research design is not cross-cultural as such (we hardly ever perform comparisons between societies), but culturally sensitive within a series of societies; in other words, as Dasen and Jahoda (1986 , p. 413) defined it, “cross-cultural developmental psychology is not just comparative: essentially it is an outlook that takes culture seriously.”

Yupno Number System and Counting

The starting point of this study is the apparent contradiction between the existence in Yupno (Papua New Guinea) culture of an elaborate number system and the lack of importance attributed to counting in everyday life. The study is designed to answer two questions: To what extent is the model described by the socially most prestigious expert shared by other Yupno men? How can the system be used to solve new, unfamiliar problems? Indeed, the variability found in the description and use of the number system is very important, to the extent where almost each subject uses it in a slightly different, idiosyncratic way. Without the help of a psychological perspective, this astounding variability may have gone unnoticed. However, to the anthropologist, it is too early to speak of a "requiem for the omniscient informent" because the ideal model "fits" with the rest of the culture-for example, the symbolic separation between the left and right parts of the body. Arithmetic computations can be performed by the older Yupno men using the traditional Yupno system and by children using school algorithms but not by those young men who are in between two cultures.

Number concepts without number lines in an indigenous group of Papua New Guinea

BACKGROUND

The generic concept of number line, which maps numbers to unidimensional space, is a fundamental concept in mathematics, but its cognitive origins are uncertain. Two defining criteria of the number line are that (i) there is a mapping of each individual number (or numerosity) under consideration onto a specific location on the line, and (ii) that the mapping defines a unidimensional space representing numbers with a metric--a distance function. It has been proposed that the number line is based on a spontaneous universal human intuition, rooted directly in brain evolution, that maps number magnitude to linear space with a metric. To date, no culture lacking this intuition has been documented.

METHODOLOGY/PRINCIPAL FINDINGS

By means of a number line task, we investigated the universality proposal with the Yupno of Papua New Guinea. Unschooled adults did exhibit a number-to-space mapping (criterion i) but, strikingly, despite having precise cardinal number concepts, they located numbers only on the endpoints, thus failing to use the extent of the line. The produced mapping was bi-categorical and metric-free, in violation of criterion ii. In contrast, Yupnos with scholastic experience used the extent of the segment according to known standards, but they did so not as evenly as western controls, exhibiting a bias towards the endpoints.

CONCLUSIONS/SIGNIFICANCE

Results suggest that cardinal number concepts can exist independently from number line representations. They also suggest that the number line mapping, although ubiquitous in the modern world, is not universally spontaneous, but rather seems to be learned through--and continually reinforced by--specific cultural practices.

Hydrothermal ceramic for porcelain-fused-to-metal crowns: an initial experience report from clinical practice

The development of hydrothermal ceramics was an important requirement for fusing hydrolysis-resistant ceramics to precious metal alloys with low melting interval. Clinical findings since 1992 confirm the wide range of application of these metal-ceramic restorations in dentistry. Initial problems concerning temperature regulation of the ceramic ovens were rectified by checking and adjusting them for lower sintering temperatures. The golden yellow color is only one advantage of the ceramic-veneered alloy. Other advantages include its nonporous, smooth surface, translucence, and suitability for use in all types of dental restorations and reconstructions. Hydrothermal ceramic veneers thus can help to substantially reduce the number of different alloys used in a patient's mouth.