Relative sensitivity of the mutual exclusivity and novel-name-nameless category assumptions

The mutual exclusivity (ME) assumption states that children affix a novel label to only one unfamiliar object, while the novel-name-nameless category (N3C) assumption states that children affix a novel label to multiple unfamiliar objects. To compare the relative sensitivity of the two assumptions, two types of tasks, with two trials in each, were given to 5-year-olds. In the first trial of each task, all children selected only the unfamiliar object for a novel label, which was consistent with the ME assumption. For the task which did not have the same unfamiliar object in the two trials, 94% of the children selected the object with the same shape but black-white reversed image in the second trial, which was consistent with the N3C assumption. For the task which had the same unfamiliar object in the two trials, 43% of the children selected the same object in the second trial, which was consistent with the ME assumption, and 48% of them selected the object with the same shape but reversed image, which was consistent with the N3C assumption. The findings suggest that the ME and N3C assumptions can be flexibly applied to children's word learning.     

Experimental study on co-evolution of categorical perception and communication systems in humans

In this paper, we present an experiment that integrates a semiotic investigation with a dynamical perspective on embodied social interactions. The primary objective is to study the emergence of a communication system between two interacting individuals, where no dedicated communication modalities are predefined and the only possible interaction is very simple, non-directional, and embodied. Throughout the experiment, we observe the following three phenomena: (1) the spontaneous emergence of turn-taking behaviour that allows communication in non-directional environments; (2) the development of an association between behaviours and perceptive categories; (3) the acquisition of novel meaning by exploiting the notion of complementary set theory.     

Low income, unemployment, and suicide mortality rates for middle-age persons in Japan

The relationships between age-specific suicide mortality rates and social life factors for all 47 Japanese prefectures in 1980, 1985, and 1990 were assessed by multiple regression analysis after factor analysis on 20 social life indicators. During this period, Japan experienced a secondary oil crisis in 1980-1983 and a bubble economy in 1986-1990. It was concluded that (1) low income was the major determinant which positively affected suicide mortality rate in middle-aged men during a previous 20-yr. period (1970-1990), (2) urbanization was negatively associated with male suicide mortality rates in most of the age classes in the 1980s, (3) unemployment was one of the major determinants of increased suicide mortality rate in middle-age men in the 1980s, and (4) unemployment was the major factor which was inversely associated with suicide mortality rate for elderly women from 1980 to 1990 in Japan.