With increasing demand for autonomy and adaptivity of robots the focus of research on intelligent systems progressively moved from the direct solving of one specific task to more sophisticated approach of learning tasks up to the highest level where the systems decide themselves what to learn and when. Inspired by the example of child development modern research targets a similar process in artificial systems. The expected benefits are higher adaptivity, no necessity to redesign the system for changed tasks, and a break through the limits of the complexity of hand-designed behaviors. The...