Post-decision wagering measures metacognitive content, not sensory consciousness

A recent report by Persaud et al. [Persaud, N., McLeod, P. & Cowey, A. (2007). Post-decision wagering objectively measures awareness. Nature Neuroscience 10, 257-261] addresses a fundamental issue in consciousness science: the experimental measurement of conscious content. The authors propose a novel technique, 'post-decision wagering', in which subjects place bets on the correctness of decisions or discriminations. In this note, I critique the authors' claim that their method "measures awareness directly".