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 for them to be accepted as an expert. In this respect, a shepherd with 50 years of experience tending flocks would be widely recognized as having complete expertise in the use and training of sheep dogs and the care of sheep. Another example from computer science is that an expert system may be taught by a human and thereafter considered an expert, often outperforming human beings at particular tasks. In law, an expert witness must be recognized by argument and authority. Research in this area attempts to understand the relation between expert knowledge, skills and personal characteristics and exceptional performance.