PITCH MEMORY FOR NEAR THRESHOLD STIMULUS DIFFERENCES.
Abstract
The increasing range of active sonar contacts raises questions concerning the ability of the operator to detect very small amounts of Doppler, when the reverberation and echo are separated in time. To get some data relevant to this problem, an investigation of memory for the pitch of a short duration pure tone pulse was conducted. Utilizing an 800 cps standard stimulus with comparison stimulus separations of 0, + or - 3, + or - 4, + or - 5 cps, discriminability and constant error measures were taken with .95, 4.5, and 8.9 sec interstimulus separations. The data justify the following conclusions: (1) pitch discrimination shows no reliable change over the interval from .95 to 8.9 sec; (2) the nature of the incorrect responses indicates an increasing willingness to report a pitch difference as the interstimulus interval increases; (3) a bias in reporting more lower than higher pitch differences at the .95 sec interval reverses at 4.5 sec, and is absent at 8.9 sec; (4) the data are consistent with much previous research involving pure tone discrimination, and with most of the data on Doppler discrimination employing sonar stimulus materials. It is inferred that no decline in near threshold Doppler judgments is likely up to about a 9 sec separation between reverberation and echo. However, specific training against high and low Doppler response biases at certain time separations is indicated. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1966
- Accession Number
- AD0482390
Entities
People
- A. W. Lau
- E. G. Aiken