Constancy and normalization in the perception of Voice Offset Time as a cue for preaspiration.

It is a well-established fact that the realization of individual speech segments is heavily dependent on context. One factor, temporal organization, has been shown to affect numerous speech cues, especially those which are defined in the temporal domain. Theories of speech perception have adopted two different views of the nature of these contextual effects. On the one hand it has been hypothesized that the listener normalizes by taking account of the context. On the other hand it has been hypothesized that higher-order invariants, e.g. speech segment ratios, are sufficient cues for the relevant temporal contrasts, thus obviating the need for mechanisms of normalization. The present series of experiments investigates the merits of these opposing theoretical positions. The experiments involve Voice Offset Time as a cue for preaspiration in Icelandic. The results indicate that durational ratios can, for the most part, function as higher-order invariants for the perception of preaspiration.