Mechanisms mediating the perception of complex acoustic patterns

Many sounds of ecological importance consist of complex acoustic patterns, and the research conducted during the previous grant has dealt with some of the rules and mechanisms governing the perception of such sounds. Using randomly derived waveforms (frozen noise segments) as model long period complex sounds, a series of experiments examined aspects of the stimuli used for recognition, and tested hypotheses concerning the basic principles governing the perception of these sounds. New evidence was reported indicating that sequences of brief tones and brief vowels are perceived as global patterns or temporal compounds. Different arrangements of component sounds form distinctive compounds, so that permuted orders can be discriminated without resolution into component elements. The same basic rules govern the perception of frozen noises, sequences of tones, and sequences of vowels, with overlays of special rules for melodic and phonetic sequences.