Pamela Heaton

Autism and Pitch Processing: A Precursor for Savant Musical Ability?

Musically naive autistic children were compared with musically naive mental age-matched control subjects for their ability to identify and remember single-note frequencies or speech sounds. As an analogy to testing for absolute pitch, subjects were asked after two different time intervals to point out animal pictures previously paired with these stimuli. The results showed that although both groups identified and recalled speech sounds equally well, those with autism demonstrated a superior ability for single-note identification over both time intervals. The findings are discussed in terms of an enhanced capacity, characteristic of autistic persons, to process and retain isolated, context-independent elements of stimulus arrays.

Pitch memory, labelling and disembedding in autism.

BACKGROUND Autistic musical savants invariably possess absolute pitch ability and are able to disembed individual musical tones from chords. Enhanced pitch discrimination and memory has been found in non-savant individuals with autism who also show superior performance on visual disembedding tasks. These experiments investigate the extent that enhanced disembedding ability will be found within the musical domain in autism. METHOD High-functioning children with autism, together with age- and intelligence-matched controls, participated in three experiments testing pitch memory, labelling and chord disembedding. RESULTS The findings from experiment 1 showed enhanced pitch memory and labelling in the autism group. In experiment 2, when subjects were pre-exposed to labelled individual tones, superior chord segmentation was also found. However, in experiment 3, when disembedding performance was less reliant on pitch memory, no group differences emerged and the children with autism, like controls, perceived musical chords holistically. CONCLUSION These findings indicate that pitch memory and labelling is superior in autism and can facilitate performance on musical disembedding tasks. However, when task performance does not rely on long-term pitch memory, autistic children, like controls, succumb to the Gestalt qualities of chords.

Enhanced perceptual processing of speech in autism

Theories of autism have proposed that a bias towards low-level perceptual information, or a featural/surface-biased information-processing style, may compromise higher-level language processing in such individuals. Two experiments, utilizing linguistic stimuli with competing low-level/perceptual and high-level/semantic information, tested processing biases in children with autism and matched controls. Whereas children with autism exhibited superior perceptual processing of speech relative to controls, and showed no evidence of either a perceptual or semantic processing bias, controls showed a tendency to process speech semantically. The data provide partial support to the perceptual theories of autism. It is additionally proposed that the pattern of results may reflect different patterns of attentional focusing towards single or multiple stimulus cues in speech between children with autism and controls.

Veridical mapping in the development of exceptional autistic abilities.

Superior perception, peaks of ability, and savant skills are often observed in the autistic phenotype. The enhanced perceptual functioning model (Mottron et al., 2006a) emphasizes the increased role and autonomy of perceptual information processing in autistic cognition. Autistic abilities also involve enhanced pattern detection, which may develop through veridical mapping across isomorphic perceptual and non-perceptual structures (Mottron et al., 2009). In this paper, we elaborate veridical mapping as a specific mechanism which can explain the higher incidence of savant abilities, as well as other related phenomena, in autism. We contend that savant abilities such as hyperlexia, but also absolute pitch and synaesthesia, involve similar neurocognitive components, share the same structure and developmental course, and represent related ways by which the perceptual brain deals with objective structures under different conditions. Plausibly, these apparently different phenomena develop through a veridical mapping mechanism whereby perceptual information is coupled with homological data drawn from within or across isomorphic structures. The atypical neural connectivity characteristic of autism is consistent with a developmental predisposition to veridical mapping and the resulting high prevalence of savant abilities, absolute pitch, and synaesthesia in autism.

Can children with autistic spectrum disorders perceive affect in music? An experimental investigation

BACKGROUND Children with autistic spectrum disorders typically show impairments in processing affective information within social and interpersonal domains. It has yet to be established whether such difficulties persist in the area of music; a domain which is characteristically rich in emotional content. METHODS Fourteen children with autism and Asperger syndrome and their age and intelligence matched controls were tested for their ability to identify the affective connotations of melodies in the major or minor musical mode. They were required to match musical fragments with schematic representations of happy and sad faces. RESULTS The groups did not differ in their ability to ascribe the musical examples to the two affective categories. CONCLUSIONS In contrast to their performance within social and interpersonal domains, children with autistic disorders showed no deficits in processing affect in musical stimuli.

Superior discrimination of speech pitch and its relationship to verbal ability in autism spectrum disorders

Whilst hypersensitivity to pitch information appears to be characteristic of many individuals with autism spectrum disorders little is known about the implications of such a tendency for language acquisition and development. Discrimination of systematically varied pitch differences between pairs of words, nonwords, and nonspeech pitch contour analogues was assessed in children with autism spectrum disorders (ASD) and matched controls. The findings revealed superior performance in ASD, although, like controls, discrimination of pitch in speech stimuli was poorer in this group than for nonspeech stimuli. Whilst it was hypothesized that enhanced processing of speech pitch would correlate negatively with receptive language skills in ASD, the findings did not fully support this, and enhanced discrimination skills were observed in individuals without significant language impairment. The implications of these findings for understanding heterogeneity of language ability in ASD are discussed.

Research note: Exceptional absolute pitch perception for spoken words in an able adult with autism

Autism is a neurodevelopmental disorder, characterised by deficits in socialisation and communication, with repetitive and stereotyped behaviours [American Psychiatric Association (1994). Diagnostic and statistical manual for mental disorders (4th ed.). Washington, DC: APA]. Whilst intellectual and language impairment is observed in a significant proportion of diagnosed individuals [Gillberg, C., & Coleman, M. (2000). The biology of the autistic syndromes (3rd ed.). London: Mac Keith Press; Klinger, L., Dawson, G., & Renner, P. (2002). Autistic disorder. In E. Masn, & R. Barkley (Eds.), Child pyschopathology (2nd ed., pp. 409-454). New York: Guildford Press], the disorder is also strongly associated with the presence of highly developed, idiosyncratic, or savant skills [Heaton, P., & Wallace, G. (2004) Annotation: The savant syndrome. Journal of Child Psychology and Psychiatry, 45 (5), 899-911]. We tested identification of fundamental pitch frequencies in complex tones, sine tones and words in AC, an intellectually able man with autism and absolute pitch (AP) and a group of healthy controls with self-reported AP. The analysis showed that ACs naming of speech pitch was highly superior in comparison to controls. The results suggest that explicit access to perceptual information in speech is retained to a significantly higher degree in autism.

Autism and pitch processing splinter skills A group and subgroup analysis

Autism is characterized by an uneven profile of cognitive abilities and population studies show that approximately 10 percent of diagnosed individuals possess a skill that is significantly better than would be predicted by global IQ. Recent evidence suggests that individuals with autism who possess special skills may represent a distinct genetic group within the autism spectrum. Intellectually high- and low-functioning children and adolescents with autism, together with age- and intelligence-matched comparison participants, completed two experiments that tested pitch discrimination and pitch memory within a visuo-spatial format. The analysis of the data from the studies showed that a subgroup of individuals with autism achieved performance scores that were between four and five standard deviations above the mean for the groups. Unlike comparison participants, their performance appeared to be independent of intelligence, musical training and experience. The findings were interpreted within the context of neuroconstructivist models of typical development and delayed language acquisition characteristic of autism and other neurodevelopmental disorders.

Assessing musical skills in autistic children who are not savants

Descriptions of autistic musical savants suggest that they possess extraordinary skills within the domain. However, until recently little was known about the musical skills and potential of individuals with autism who are not savants. The results from these more recent studies investigating music perception, cognition and learning in musically untrained children with autism have revealed a pattern of abilities that are either enhanced or spared. For example, increased sensitivity to musical pitch and timbre is frequently observed, and studies investigating perception of musical structure and emotions have consistently failed to reveal deficits in autism. While the phenomenon of the savant syndrome is of considerable theoretical interest, it may have led to an under-consideration of the potential talents and skills of that vast majority of autistic individuals, who do not meet savant criteria. Data from empirical studies show that many autistic children possess musical potential that can and should be developed.

An evaluation of the fairness of police line-ups and video identifications

Mistaken eyewitness identification is a major source of miscarriages of justice. In England and Wales, procedures for obtaining identification evidence are set out in legislation. The vast majority of identifications are obtained using a traditional ‘live’ identity parade (or line-up). However, in some circumstances video identifications are being used more frequently. Records of line-ups and video identifications used in actual criminal cases were obtained. The fairness of these two procedures was compared by use of a mock witness procedure. In a perfectly fair line-up the suspect would be chosen, by chance, by 11% of the mock witnesses. However, 25% of mock witnesses selected the suspect from 25 photographs of live line-ups, compared to 15% of mock witnesses who selected the suspect from video identifications. An analysis of covariance, taking the number of visual features mentioned in the original witnesss first description as the covariate, showed that the proportion choosing the suspect was significantly smaller from video identifications. It is concluded that the video line-ups were fairer than the live line-ups, and therefore that wider use of video identifications has the potential to improve the reliability of eyewitness identification evidence.