The aim of this research is to identify the factors that determine listeners' abilities to detect, discriminate, or identify, events within various types of auditory and audiovisual patterns. Patterns to be studied include sequences of tones, spectrally complex non-speech sounds, speech, and audiovisual stimuli. Four related lines of investigation are planned. 1. Attention to information in patterns of tones. This line of investigation will utilize adaptive tracking procedures to assess changes in detection thresholds and frequency resolving power for pure tones in patterns as the deviation from the expected temporal onset or frequency of a target tone varies. 2. Attention to events in patterns of spectrally complex sounds. This research will focus on the discrimination of spectrally complex events within temporal patterns. The experiments will examine-the targeting of attention in patterns of spectrally complex sounds following procedures similar to those used with pure tones. 3. Dynamic expectancies in speech_perception. The influence of dynamic expectancies on the identification of speech sounds will be studied in this continuation of research on articulatory-rate context effects (Kidd, 1989). The observed effect of rate expectations on the perception of voicing in stop consonants will be examined in a variety of speech contexts to test the generality of the effect and to determine more precisely the basis for the generation of temporal expectancies in speech. 4. Attending to two modalities: The perception of audiovisual stimuli. Cross-modality influences on attention to information in dynamic audiovisual displays will be examined using non-speech stimuli. This investigation will determine the extent to which dynamic expectancies based on visual information can facilitate auditory perception. Listeners with different levels of lip-reading proficiency and auditory capabilities will be tested.