When we view an ambiguous display, its visual appearance continues to fluctuate between two or more alternative states (Blake & Logothetis,
2002; Leopold & Logothetis,
1999; Sterzer, Kleinschmidt, & Rees,
2009). Several factors are thought to contribute to the temporal evolution of such “multistable percepts”: first, the neural representations of alternative appearances inhibit each other, so that exactly one appearance dominates at any moment (Alais, Cass, O'Shea, & Blake,
2010; Blake, Westendorf, & Fox,
1990). Second, neural adaptation progressively destabilizes the currently dominant appearance, limiting its duration (Kang & Blake,
2010; Nawrot & Blake,
1989; Petersik,
2002; Wolfe,
1984). Third, stochastic fluctuations of neural activity initiate reversals at irregular intervals (Brascamp, van Ee, Noest, Jacobs, & van Den Berg,
2006; Hollins,
1980; Kim, Grabowecky, & Suzuki,
2006). Fourth, volitional processes, such as eye movements, eye blinks, or attention shifts, may also trigger reversals of appearance (Leopold, Wilke, Maier, & Logothetis,
2002; Mitchell, Stoner, & Reynolds,
2004; van Dam & van Ee,
2006, but see Pastukhov & Braun,
2007).