R&D, learning, and phases of economic growth

The role of learning and R&D in economic development is addressed in an end ogenous growth model. When human capital is below a threshold level, the mo del predicts that skills are accumulated as the only growth-generating acti vity, whereas both innovation activities and learning drive growth above th is level. Hence, an endogenous regime shift is triggered when the level of human capital reaches the threshold level because it becomes profitable to innovate.