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Jessica M Foxton

Publications and source records attributed to Jessica M Foxton.

6 recordsLinked to original sources
PubMed2006

Rhythm deficits in 'tone deafness'.

It is commonly observed that 'tone deaf' individuals are unable to hear the beat of a tune, yet deficits on simple timing tests have not been found. In this study, we investigated rhythm processing in nine individuals with congenital amusia ('tone deafness') and nine controls. Participants were presented with pairs of 5-note sequences, and were required to detect the presence of a lengthened interval. In different conditions the sound sequences were presented isochronously or in an integer-ratio rhythm, and these were either monotonic or varied randomly in pitch. It was found that the 'tone deaf' participants exhibited inferior rhythm analysis for the sequences that varied in pitch compared to those that did not, whereas the controls obtained equivalent thresholds for these two conditions. These results suggest that the rhythm deficits in congenital amusia result from the pitch-variations in music.

Acoustic Stimulation↗
PubMed2004

Musically tone-deaf individuals have difficulty discriminating intonation contours extracted from speech.

Musically tone-deaf individuals have psychophysical deficits in detecting pitch changes, yet their discrimination of intonation contours in speech appears to be normal. One hypothesis for this dissociation is that intonation contours use coarse pitch contrasts which exceed the pitch-change detection thresholds of tone-deaf individuals (). We test this idea by presenting intonation contours for discrimination, both in the context of the original sentences in which they occur and in a "pure" form dissociated from any phonetic context. The pure form consists of gliding-pitch analogs of the original intonation contours which exactly follow their pattern of pitch and timing. If the spared intonation perception of tone-deaf individuals is due to the coarse pitch contrasts of intonation, then such individuals should discriminate the original sentences and the gliding-pitch analogs equally well. In contrast, we find that discrimination of the gliding-pitch analogs is severely degraded. Thus it appears that the dissociation between spoken and musical pitch perception in tone-deaf individuals is due to a deficit at a higher level than simple pitch-change detection.

Adult↗
PubMed2004

Characterization of deficits in pitch perception underlying 'tone deafness'.

Congenital amusia is a disorder characterized by life-long, selective deficits in the perception of music. This study examined pitch-perception abilities in a group of 10 adults with this disorder. Tests were administered that assessed fine-grained pitch perception by determining thresholds both for the detection of continuous and segmented pitch changes, and for the recognition of pitch direction. Tests were also administered that assessed the perception of more complex pitch patterns, using pitch-sequence comparison tasks. In addition, the perceptual organization of pitch was also examined, using stream segregation tasks that assess the assignment of sounds differing in pitch to one or two distinct perceptual sources. In comparison with 10 control subjects, it was found that the participants with congenital amusia exhibited deficits both at the level of detecting fine-grained differences in pitch, and at the level of perceiving patterns in pitch. In contrast, no abnormalities were identified in the perceptual organization of pitch. The pitch deficits identified are able to account for the music perception difficulties in this disorder, and implicate deficient cortical processing.

Acoustic Stimulation↗
PubMed2004

Training improves acoustic pattern perception.

Pitch changes that occur in speech and melodies can be described in terms of contour patterns of rises and falls in pitch and the actual pitches at each point in time. This study investigates whether training can improve the perception of these different features. One group of ten adults trained on a pitch-contour discrimination task, a second group trained on an actual-pitch discrimination task, and a third group trained on a contour comparison task between pitch sequences and their visual analogs. A fourth group did not undergo training. It was found that training on pitch sequence comparison tasks gave rise to improvements in pitch-contour perception. This occurred irrespective of whether the training task required the discrimination of contour patterns or the actual pitch details. In contrast, none of the training tasks were found to improve the perception of the actual pitches in a sequence. The results support psychological models of pitch processing where contour processing is an initial step before actual pitch details are analyzed. Further studies are required to determine whether pitch-contour training is effective in improving speech and melody perception.

Acoustic Stimulation↗
PubMed2003

Absence of auditory 'global interference' in autism.

There has been considerable recent interest in the cognitive style of individuals with Autism Spectrum Disorder (ASD). One theory, that of weak central coherence, concerns an inability to combine stimulus details into a coherent whole. Here we test this theory in the case of sound patterns, using a new definition of the details (local structure) and the coherent whole (global structure). Thirteen individuals with a diagnosis of autism or Asperger's syndrome and 15 control participants were administered auditory tests, where they were required to match local pitch direction changes between two auditory sequences. When the other local features of the sequence pairs were altered (the actual pitches and relative time points of pitch direction change), the control participants obtained lower scores compared with when these details were left unchanged. This can be attributed to interference from the global structure, defined as the combination of the local auditory details. In contrast, the participants with ASD did not obtain lower scores in the presence of such mismatches. This was attributed to the absence of interference from an auditory coherent whole. The results are consistent with the presence of abnormal interactions between local and global auditory perception in ASD.

Acoustic Stimulation↗