Regarding Arturo Camacho's question about the minimum duration required in a sinusoid to hear pitch: by "pitch", I take to mean any sense of tonality at all. If so, the references are:
Burck, W., Kotowski, P., and Lichte, H. (1935). Die lautstarke von knacken, gerauschen und tonen. Elektrische Nachrichten-Technik 12, 326-333. (in German, but understandable with some educated guesswork)
Bentzen, O. (1950). A new apparatus for producing short tones, and some experiments performed with it. Acta Laryngologica Supplementum 95, 116-126.
Miskolczy-Fodor, F. (1953). Monaural loudness-balance-test and determination of recruitment-degree with short sound-impulses. Acta Oto-Laryngologica 43, 573-595.
Such issues interest me because of my experimental use of ultrashort tone pulses (see papers in JASA) that are often too brief to have tonality.
Lance Nizami, PhD