Autism-ness Does Not Exist, but Autism Does, Part 2: The Perception-Language Chimera Model Accounts for the Nature, Chronology, and Interrelation of Autistic Signs.

One of the most influential attempts to characterize and explain the perceptual atypicalities of autism, as well as their relationship to the linguistic and social features of the condition, is the "enhanced perceptual functioning" (EPF) model. This model proposes stronger performance, an increased role, and greater autonomy of perception relative to other cognitive functions, and explains early language delay in autism as a temporary reliance on non-linguistic, perceptual processing of language. This paper presents an updated and reconceptualized version of the EPF framework, informed by accumulated knowledge of early language development and perceptual trajectories in autistic toddlers over the past two decades. The language-perception chimera model proposes that, due to a loss of the bias that typically prioritizes social information, the parental voice loses its unique status in triggering first-language acquisition. Consequently, the innate human drive to recognize, acquire, and master language becomes redirected toward its structural, non-communicative components. The selection, search, inspection, and manipulation of structural redundancies-characteristic of repetitive autistic behaviours-may therefore arise from the extension, to non-linguistic domains, of a mechanism through which children identify the language they will acquire. Seven arguments, based on cross-sectional and longitudinal observations of the early manifestations of prototypical autism, support this model. (1) Bayonet-shaped language trajectory: prototypical autism is preceded by reduced social interest and increased attention to non-social material. A plateau without communicative language follows the absence or regression of the few oral words typically acquired by 18 months. Later, language recovery, often including syntax, is delayed but common. (2) During this plateau, early interest in letters and occasional unexpected bilingualism indicate a spontaneous yet diverted orientation toward language. (3) Contemporaneous complex perception-based signs are highly specific to prototypical autism and contribute significantly to diagnostic certainty. (4) Early perception-based behaviours focus strongly on structural patterns. (5) Non-social language entry and complex perceptual behaviours arise when typically developing children experience a lexical and syntactic surge. (6) Veridical mapping phenomena and neuroimaging findings reveal enhanced pattern-language relationships. (7) The perception-language chimera can also account for certain savant abilities. When combined with a reconceptualization of autism as an asymmetric developmental bifurcation, the language-perception chimera model is the first to explain the occurrence, nature, idiosyncrasies, combinations, and developmental trajectories of the majority of social, language, and repetitive features observed in prototypical autism. This framework also clarifies the extent to which the innate mechanisms underlying language detection and acquisition in typical development are truly language-specific, as opposed to domain-general cognitive processes that converge to support language acquisition.