Motivation of play: from ethological to neurological perspectives

The collection of papers presented in this Special Issue is the outcome of a series of workshops on the evolution of play held between 2011 and 2013 and sponsored by the National Institute of Mathematical and Biological Synthesis (NIMBioS) at the University of Tennessee (Knoxville, TN, USA). These workshops were aimed at stimulating a multidisciplinary discussion about one of the most debated and controversial behaviours in the Animal Kingdom. Although neglected for a long time by researchers studying non-human animals, play research seems to be having a new Renaissance and the last ten years have been extremely fruitful in highlighting some important functions and in delineating key correlates of this activity. Obviously, it is impossible to fully represent such a multifaceted topic as play in a handful of papers; however, the articles in this Special Issue bring to light some over-arching themes and together provide innovative perspectives on play