We utilize county-level data to explore the roles of different types of human capital accumulation in U.S. growth determination. The data includes over 3,000 cross-sectional observations and 39 demographic control variables. The large number of observations provides enough degrees of freedom to...

Human capital plays an important role in the theory of economic growth, but it has been difficult to measure this abstract concept. We survey the psychological literature on cross-cultural IQ tests, and conclude that modern intelligence tests are well-suited for measuring an important form of a...

If bigger objects go into a jar, then there will be space to fill it with smaller objects in sequence. If the order of the objects are reversed, then it ends in filling it at the starting point. Happiness in life is similar to this. Fill high priority needs in the life, and smaller needs can be...

I show that in a conventional Ramsey model, between one-fourth and one- half of income differences across countries can be explained by a single factor: The steady-state effect of large, persistent differences in national average IQ on worker productivity. These differences in cognitive...