ABSTRACT
Motivation to achieve and to improve skills is an important characteristic of our and other species. One can think of many vignettes of young organisms struggling to master problems: the young fledgling flapping its wings, jumping and hopping in its attempts to start to fly; the baby pulling herself or himself up on to chairs in the first attempts to start to walk, or the concentration and sometimes frustration of the toddler attempting to solve a puzzle. In all cases there is a strong motive directing behaviour, and the motive is not related to any immediate physical reward. Instead, the mastery of the task appears to be a reward in itself. The fascination of this type of behaviour provides the basis for the present volume.
