Related Experiment Video
Updated: May 13, 2026

Four Temporary Waterslide Designs Adapted to Different Slope Conditions to Encourage Child Socialization in Playgrounds
Published on: December 9, 2022
The emergence of three human development clubs
Sebastian Vollmer1, Hajo Holzmann, Florian Ketterer
1Department of Economics and Courant Research Center Poverty, Equity and Growth in Developing Countries, University of Göttingen, Göttingen, Germany. svollmer@uni-goettingen.de
Abstract:
We examine the joint distribution of levels of income per capita, life expectancy, and years of schooling across countries in 1960 and in 2000. In 1960 countries were clustered in two groups; a rich, highly educated, high longevity "developed" group and a poor, less educated, high mortality, "underdeveloped" group. By 2000 however we see the emergence of three groups; one underdeveloped group remaining near 1960 levels, a developed group with higher levels of education, income, and health than in 1960, and an intermediate group lying between these two. This finding is consistent with both the ideas of a new "middle income trap" that countries face even if they escape the "low income trap", as well as the notion that countries which escaped the poverty trap form a temporary "transition regime" along their path to the "developed" group.
Related Concept Videos
Three Developmental Domains
Physical Development
Physical processes, also known as maturation, encompass the biological changes that occur across an individual's life. These changes begin with genetic inheritance and continue through various stages, including growth in height and weight,...
Emerging Adulthood
Introduction to Developmental Psychology
Sustainable Development
Impact of Groups on Individuals
Impact of Groups on Groups
