Four artists in contention for 2013 Turner Prize

Nominated are Glasgow-based David Shrigley, for his solo exhibition Brain Activity at London's Hayward Gallery; Lynette Yiadom-Boakye, shortlisted for her Extracts and Verses exhibition at the Chisenhale Gallery; Laure Prouvost , for her new work Wantee; and  Tino Sehgal, who makes the list for his  projects This Variation and These Associations.