Isabelline (colour) form of leucism caused by a uniform reduction in the production and expression of melanin resulting in areas of plumage on the back of the bird, normally black, being strongly faded, or isabelline, in appearance. Isabellinism has been reported in several species of penguin. Isabelline and isabella are terms applied in Europe to very pale palomino or cremello horses, animals with a coat colour that is variously described as cream, pale gold or almost white; this is the primary usage of the French ("isabelle") and German ("Isabella") versions of the word. In horses, this colour is created by the action
Expert Simon and Kevin Gilmartin proposed a model of learning in chess called MAPP (Memory-Aided Pattern Recognizer). Based on simulations, they estimated that about 50,000 chunks (units of memory) are necessary to become an expert, and hence the many years needed to reach this level. More recently, the CHREST model (Chunk Hierarchy and REtrieval STructures) has simulated in detail a number of phenomena in chess expertise (eye movements, performance in a variety of memory tasks, development from novice to expert) and in other domains. An important feature of expert performance seems to be the way in which experts are able to