Developmental heterochrony and the evolution of autistic perception, cognition and behavior

Abstract

BackgroundAutism is usually conceptualized as a disorder or disease that involves fundamentally abnormal neurodevelopment. In the present work, the hypothesis that a suite of core autism-related traits may commonly represent simple delays or non-completion of typical childhood developmental trajectories is evaluated.DiscussionA comprehensive review of the literature indicates that, with regard to the four phenotypes of (1) restricted interests and repetitive behavior, (2) short-range and long-range structural and functional brain connectivity, (3) global and local visual perception and processing, and (4) the presence of absolute pitch, the differences between autistic individuals and typically developing individuals closely parallel the differences between younger and older children.SummaryThe results of this study are concordant with a model of ‘developmental heterochrony’, and suggest that evolutionary extension of child development along the human lineage has potentiated and structured genetic risk for autism and the expression of autistic perception, cognition and behavior.

Fragile Spectral and Temporal Auditory Processing in Adolescents with Autism Spectrum Disorder and Early Language Delay

“…Autism spectrum disorder (ASD) refers to a spectrum of early onset neurodevelopmental disorders characterised by poor social reciprocity and communication, combined with repetitive and stereotyped patterns of behaviour, interests and activities (American Psychiatric Association 2000, 2013. Hyper and hyposensitivity to sensory stimulation (e.g., Kern et al 2006;Khalfa et al 2004) as well as atypical sensory processing abilities (e.g., Leekam et al 2007;Simmons et al 2009;Talay-Ongan and Wood 2000) are often reported and have been included in the new diagnostic criteria of ASD in DSM-5 (American Psychiatric Association 2013).…”

“…Hyper and hyposensitivity to sensory stimulation (e.g., Kern et al 2006;Khalfa et al 2004) as well as atypical sensory processing abilities (e.g., Leekam et al 2007;Simmons et al 2009;Talay-Ongan and Wood 2000) are often reported and have been included in the new diagnostic criteria of ASD in DSM-5 (American Psychiatric Association 2013). Delayed or deviant speech and language development are also often reported but are no longer incorporated in the diagnostic criteria of the disorder (American Psychiatric Association 2000, 2013.…”

“…It has been suggested that the increased sensitivity to fine-grained spectral changes may impede speech development in ASD by generating overly specific categories of sounds that inhibit learning of higher-level abstract patterns (Crespi 2013;Järvinen-Pasley et al 2008a, b;Van de Cruys et al 2014). In typically developing infants there is a natural shift from an initial focus on absolute pitch to the eventual dominance of relative pitch (Saffran and Griepentrog 2001;Stalinski and Schellenberg 2010).…”

“…Learning to ignore absolute pitch in favor of relative distances is necessary in order to generate general and abstract speech sound categories. Relying on absolute pitch information, instead, would result in overly specific categories of sounds with little room for generalization (Crespi 2013;Saffran and Griepentrog 2001). Relevant in this regard is the observation that 7-month-olds can only generalize words across voices when the speakers are of the same sex, but not when speakers differ in sex, presumably due to the different frequency ranges of male and female voices.…”

First principles of Hamiltonian medicine

“…Surprisingly, among individuals with relatively high-functioning autism, the frequency of insecure attachment is not increased over normative levels [140]. Children with autism certainly tend to impose higher time and energy demands on parents, especially the mother, but the degree to which less extreme and non-pathological autism spectrum phenotypes involve 'overly secure' attachment, which retains elements of early childhood, psychologically simple dependency on the mother [141], remains to be evaluated.…”