title: The verbal transformation effect and the perceptual organization of speech: influence of formant transitions and F0-contour continuity.
abstract: This study explored the role of formant transitions and F0-contour continuity in binding together speech sounds into a coherent stream. Listening to a repeating recorded word produces verbal transformations to different forms; stream segregation contributes to this effect and so it can be used to measure changes in perceptual coherence. In experiment 1, monosyllables with strong formant transitions between the initial consonant and following vowel were monotonized; each monosyllable was paired with a weak-transitions counterpart. Further stimuli were derived by replacing the consonant-vowel transitions with samples from adjacent steady portions. Each stimulus was concatenated into a 3-min-long sequence. Listeners only reported more forms in the transitions-removed condition for strong-transitions words, for which formant-frequency discontinuities were substantial. In experiment 2, the F0 contour of all-voiced monosyllables was shaped to follow a rising or falling pattern, spanning one octave. Consecutive tokens either had the same contour, giving an abrupt F0 change between each token, or alternated, giving a continuous contour. Discontinuous sequences caused more transformations and forms, and shorter times to the first transformation. Overall, these findings support the notion that continuity cues provided by formant transitions and the F0 contour play an important role in maintaining the perceptual coherence of speech.
authors.affiliation: Psychology, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
authors.forename: Marcin
authors.initials: M
authors.lastname: Stachurski
authors.affiliation: Psychology, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Summers
authors.affiliation: Psychology, School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK. Electronic address: b.roberts@aston.ac.uk.
authors.forename: Brian
authors.initials: B
authors.lastname: Roberts
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000328:Adult; D001302:Audiometry, Speech; D001306:Auditory Pathways / Q000502:physiology; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D046709:Pattern Recognition, Physiological; D013018:Sound Spectrography; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013067:Speech Perception; D013997:Time Factors; D014833:Voice Quality; D055815:Young Adult