Evidence of Reduced Global Processing in Autism Spectrum Disorder.

Frith's original notion of 'weak central coherence' suggested that increased local processing in autism spectrum disorder (ASD) resulted from reduced global processing. More recent accounts have emphasised superior local perception and suggested intact global integration. However, tasks often place local and global processing in direct trade-off, making it difficult to determine whether group differences reflect reduced global processing, increased local processing, or both. We present two measures of global integration in which poor performance could not reflect increased local processing. ASD participants were slower to identify fragmented figures and less sensitive to global geometric impossibility than IQ-matched controls. These findings suggest that reduced global integration comprises one important facet of weak central coherence in ASD.

Impaired comprehension of alternating syntactic constructions in autism.

Individuals on the higher-functioning end of the autism spectrum have significant impairments in communication. Language delay can occur, particularly in syntactic or structural linguistic knowledge. However, classically observed semantic deficits generally overshadow these structural deficits. This research examined the potential effects on comprehension of dative expressions that exhibited syntactic alternation versus those that were restricted, whether in syntactic construction or through marked semantic differences in construction. Children with autism and matched neurotypical control participants were presented with a sentence battery of dative statements representing these variations in construction and were asked to display basic comprehension of the sentence meaning by identifying the recipient, or indirect object, of the dative verb. Construction, restriction, and semantic differentiation variables were analyzed for potential effects on the rate of accurate comprehension. Both groups performed with greater accuracy when dative expressions used a prepositional phrase than when the dative action was expressed in the syntax. The autism group performed more poorly when the dative expression could syntactically alternate than when it was restricted. These effects improve our knowledge of how children with autism understand alternating grammatical constructions.

Feeling, caring, knowing: different types of empathy deficit in boys with psychopathic tendencies and autism spectrum disorder.

BACKGROUND: Empathy dysfunction is one of the hallmarks of psychopathy, but it is also sometimes thought to characterise autism spectrum disorders (ASD). Individuals with either condition can appear uncaring towards others. This study set out to compare and contrast directly boys with psychopathic tendencies and boys with ASD on tasks assessing aspects of affective empathy and cognitive perspective taking. The main aim of the study was to assess whether a distinct profile of empathy deficits would emerge for boys with psychopathic tendencies and ASD, and whether empathy deficits would be associated with conduct problems in general, rather than psychopathic tendencies or ASD specifically. METHODS: Four groups of boys aged between 9 and 16 years (N = 96) were compared: 1) psychopathic tendencies, 2) ASD, 3) conduct problems and 4) comparison. Tasks were included to probe attribution of emotions to self, empathy for victims of aggression and cognitive perspective-taking ability. RESULTS: Boys with psychopathic tendencies had a profile consistent with dysfunctional affective empathy. They reported experiencing less fear and less empathy for victims of aggression than comparison boys. Their cognitive perspective-taking abilities were not statistically significantly different from those of comparison boys. In contrast, boys with ASD had difficulties with tasks requiring cognitive perspective taking, but reported emotional experiences and victim empathy that were in line with comparison boys. Boys with conduct problems did not differ from comparison boys, suggesting that the affective empathy deficit seen in boys with psychopathic tendencies was specific to that group, rather than common to all boys with conduct problems. CONCLUSIONS: Although both groups can appear uncaring, our findings suggest that the affective/information processing correlates of psychopathic tendencies and ASD are quite different. Psychopathic tendencies are associated with difficulties in resonating with other people's distress, whereas ASD is characterised by difficulties in knowing what other people think.

Brain correlates of non-symbolic numerosity estimation in low and high mathematical ability children.

Previous studies have implicated several brain areas as subserving numerical approximation. Most studies have examined brain correlates of adult numerical approximation and have not considered individual differences in mathematical ability. The present study examined non-symbolic numerical approximation in two groups of 10-year-olds: Children with low and high mathematical ability. The aims of this study were to investigate the brain mechanisms associated with approximate numerosity in children and to assess whether individual differences in mathematical ability are associated with differential brain correlates during the approximation task. The results suggest that, similarly to adults, multiple and distributed brain areas are involved in approximation in children. Despite equal behavioral performance, there were differences in the brain activation patterns between low and high mathematical ability groups during the approximation task. This suggests that individual differences in mathematical ability are reflected in differential brain response during approximation.

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 AC's 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.

The power of the positive: revisiting weak coherence in autism spectrum disorders.

This paper reexamines Frith's original concept of weak coherence, its historical origins, recent reformulations, and alternative accounts. We suggest that the key notion of reduced global integration of information, which Frith proposed to underlie the assets in local processing, has been neglected in recent accounts of autism spectrum disorders (ASD). In fact, most paradigms used to test weak coherence conflate global and local processing, often placing them in direct trade-off, so that it is not possible to tell whether patterns of performance in ASD reflect reduced global processing, increased local processing, or both. We review the literature from typical development and ASD that may be pertinent to this distinction and examine some data from our own studies. Only once tasks are devised that measure separately the effects of reduced global processing and increased local processing will it be possible to test the on-line and developmental relations between these two aspects of "weak coherence". Some preliminary ideas about these relationships are discussed, and suggestions are made for why disentangling two possibly independent dimensions of weak coherence may be timely and productive.

Beyond perception: musical representation and on-line processing in autism.

Whilst findings from experimental studies suggest that perceptual mechanisms underpinning musical cognition are preserved or enhanced in autism, little is known about how higher-level, structural aspects of music are processed. Twenty participants with autism, together with age and intelligence matched controls, completed a musical priming task in which global and local musical contexts were manipulated. The results from the study revealed no between-group differences and showed that both global and local musical contexts influenced participants' congruity judgements. The findings were interpreted within the context of studies showing weakened sensitivity to verbal/semantic information in autism.

The structure of language abilities at 4 years: a twin study.

Normal language development was studied in 310 pairs of 4-year-old twins born in the United Kingdom in 1994. Twins were assessed individually in their homes on a diverse battery of language and nonverbal measures. Rotated factor analyses indicated the presence of a general Language factor (L) as well as a general Nonverbal (NV) factor. Moderate genetic influence was found for both L and NV abilities. Bivariate genetic analysis estimated a genetic correlation of .63 between L and NV abilities, implying that over half of the genetic influence on L overlaps with genetic influence on NV. These results suggest that at age 4, genetic influences on individual differences in language overlap substantially with genetic influences on individual differences in other cognitive abilities, although perhaps less so than later in development.