Detection of infratonal repetition of frozen noise: Singularity recognition or pattern recognition?
Brad S. Brubaker, Richard M. Warren · The Journal of the Acoustical Society of America · 1987
Listeners can readily detect iteration of “frozen” Gaussian noise segments with durations up to 1 s [N. Gattman and B. Julesz, J. Acoust. Soc. Am. 35, 610 (1963)]. Is detection of repetition of these complex waveforms based upon recognition of the reoccurrence of unique features or singularities, or upon a more holistic recognition of the pattern formed by these events? To answer this question, frozen noise segments were divided into three sections of equal duration (A, B, C) that were reassembled and then repeated to form two periodic sounds (ABC)n and (ACB)n. This manipulation changed the temporal arrangement between sections but preserved singularities and repetition rate. Untrained listeners heard a series of sequence bursts consisting of either one arrangement [(ABC)n, (ABC)n, (ABC)n,…] or two alternating arrangements [(ACB)n, (ABC)n, (ACB)n,…] and judged whether successive bursts were the same or different. Discrimination was possible when the duration of the entire iterated pattern (A + B + C) was 900 ms or less, indicating that a holistic recognition of patterns operates up to the limit of echoic storage. [Work supported by AFOSR.]