Researchers generally assume that top-of-mind (TOM) brand associations represent a unique body of brand knowledge. However, this assumption has not been sufficiently tested and substantiated. This study investigates how unique TOM brand associations actually are and examines the differences between TOM and other spontaneous recalls by adopting quantitative measures from other disciplines, primarily biology. The empirical data are obtained via a large survey of past and potential Chinese outbound tourists regarding how they view the U.S. as a destination. The results indicate that TOM brand association information may effectively capture a large portion of overall brand knowledge. The theoretical and practical implications of these findings are discussed.