We found a matchYour institution may have access to this item. Find your institution then sign in to continue.TitleFive plus two equals yellow.AuthorsDixon, M J; Smilek, D; Cudahy, C; Merikle, P MPublicationNature, 2000, Vol 406, Issue 6794, p365ISSN0028-0836Publication typeJournal ArticleDOI10.1038/35019148