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Title: A study of thresholds for signals having changing pitch
Author: Pick, G. F.
ISNI:       0000 0004 2695 7134
Awarding Body: Keele University
Current Institution: Keele University
Date of Award: 1973
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In this dissertation, the threshold for stimuli with changing pitch has been discussed in terms of some simple psychophysical phenomena. The intention was to seek those effects which could not be explained in such terms, and to examine these further, especially with respect to the possibility that such effects might reflect the activity of a feature detector specific to stimuli having changing pitch. After an initial review of work by other investigators, and a description of the experimental method to be used, the experiments proper were discussed. The threshold for FM bursts, which consisted of a tone swept in frequency between given bounds, was investigated. It was noted that in many cases signals with increasing frequency showed a lower threshold than those with decreasing frequency. Another type of signal to be investigated was a white noise, to which a delayed version of itself was added; the value of the delay was the parameter modulated. The threshold for both continuous-periodic, and unidirectional modulation of delay were considered. In the unidirectional case it was noted that the threshold was lower for signals with increasing delay, i.e. for decreasing pitch. Otherwise, most of the results could be explained, at least qualitatively, in terms of spectral and temporal integration, and various temporal interactions. Evidence is provided, from backward masking experiments, that the differential threshold dependent upon the direction of glide may be explained in terms of the response of a pitch pattern recogniser. This being so, it was concluded that the experiments reported provided little or no evidence for an FM detector in man.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry