Studies by Feldhusen (1989), Kulik and Kulik (1991) and Oakes (1986) confirm what gifted educators have known for years: gifted students benefit both cognitively and affectively from working with other gifted students. Feldhusen reviewed data from several studies conducted by himself and his colleagues and concluded "...that grouping of gifted and talented students in special classes with a differentiated curriculum, or as a cluster group in a regular heterogeneous classroom (but again with differentiated curriculum and instruction), leads to higher academic achievement and better academic attitudes for the gifted and leads to no decline in achievement or attitudes for the children who remain in the regular heterogeneous classroom. Gifted and talented youth need accelerated, challenging instruction in core subject areas that parallel their special talents or aptitudes. They need opportunities to work with other gifted and talented youth. And they need... teachers who both understand the nature and needs of gifted youth and are deeply knowledgeable in the content they teach"