Exceptional abilities in autism: Theories and open questions

Abstract

The vast majority of research on autism spectrum disorder (ASD) focuses on characterizing and addressing the social communication deficits and restricted, repetitive patterns of behavior that constitute the diagnostic criteria for the disorder. Yet, a small but significant portion of individuals diagnosed with ASD exhibit exceptional cognitive abilities in one or more domains. These “twice-exceptional” individuals often have unique skills that enable them to make significant contributions to the workforce, while at the same time facing unique challenges during the transition to independent living due to a lack of services and broad public misperceptions regarding their condition. Here we review the current literature on cognitive divergence in ASD, focusing on cognitive theories, neural substrates, and clinical and societal implications for increasing understanding of this phenomenon.

Domains and definitions of exceptional abilities in autism

According to the Autism and Developmental Disabilities Monitoring Network, autism spectrum disorder (ASD) is diagnosed in one in 44 8-year-old children in the United States (Maenner et al. 2021), with the prevalence rising every time it is measured. The most recent version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) outlines diagnostic criteria for ASD which include deficits in social communication and interaction across multiple contexts and restricted, repetitive patterns of behavior (RRBs), interests or activities that are present early during development and cause significant impairment in social and occupational functioning. The vast majority of research and treatment efforts are, perhaps justifiably, devoted to ameliorating social communication deficits and addressing RRBs in individuals most severely affected by the disorder. The purpose of the current selective review is to highlight theories and empirical work focusing not on deficits, but rather strengths or exceptional abilities in ASD to identify gaps and provide a roadmap for future research on this under-studied topic.

ASD is a diagnosis that encompasses a highly heterogeneous group in terms of genetic etiology, behavioral phenotype, cognitive and intellectual function, and life outcomes. Despite the well-documented difficulties that diagnosed individuals and their families encounter, enhanced cognitive abilities and positive outcomes can also be seen. A report examining isolated skills and enhanced perceptual abilities found that these phenomena can be observed in around 60% of autistic individuals (Meilleur, Jelenic, and Mottron 2015). In a longitudinal study examining the domains of socialization, communication, independent living skills, and measures of internalizing and externalizing behaviors, over 78% of diagnosed children were doing well as assessed by proficiency and growth during mid-childhood on at least one of these domains, and over 23% were doing well in 4 or 5 of the these domains (Szatmari et al. 2021). These findings highlight the notion that the “spectrum” in ASD refers to the heterogeneity in symptom presentation and intellectual function observed in individuals who are diagnosed.

Compared with the study of social and cognitive impairments in individuals with ASD, much less research has focused on studying enhanced abilities sometimes associated with the diagnosis. Many terms have been introduced to describe enhanced abilities in autism. In this review we use the terms that the authors of the original studies used, noting that they are not in all cases clearly defined, and may not necessarily refer to the same phenomena despite superficial similarities.

Autistic individuals with enhanced abilities are sometimes referred to as “twice-exceptional”; exceptional both for having an ASD diagnosis and for having enhanced cognitive abilities in some domains. The phenomenon of “cognitive divergence” refers to exceptional cognitive strengths in one domain coupled with profound deficits in another. Additional terminology relevant to the topic of enhanced abilities in autism, and often used interchangeably in the literature, is summarized in Table 1. Difficulties with defining giftedness and the fact that educators are often not familiar with diagnosis, intervention and advocacy of twice-exceptional individuals have contributed to the relative dearth of empirical research on this topic, much of which has been descriptive (Assouline, Foley Nicpon, and Dockery 2012).

Table 1.

Relevant terminology

Term	Definition
Autism	Developmental disorder of variable severity that is characterized by difficulty with social interaction and communication and restricted, repetitive patterns of thought and behavior
Asperger syndrome	Condition differentiated from classic autism by less severe symptoms and absence of language delay (no longer a DSM diagnosis)
Savant syndrome	Condition in which an individual with developmental disabilities (including autism) displays some “island of ability” or prodigious talent, often related to calendrical calculation, mathematics, music, or art
Exceptional skill or ability in autism	Sometimes referred to as “savant skill”; an outstanding skill clearly above participant’s general level of ability and above the population norm
Giftedness	The capability to perform at higher levels compared with others of the same age and experience
Twice-exceptional	Individuals who are exceptional both for having an autism diagnosis and for having enhanced cognitive abilities in some domains
Cognitive divergence	Individuals with exceptional cognitive strengths in one domain coupled with profound deficits in another

Most readers are probably familiar with the term “savant syndrome” which describes a condition in which an individual with developmental disabilities (including autism or another disorder) displays some “island of ability” or prodigious talent, often related to calendrical calculation, mathematics, music, or art. In a savant syndrome registry including 319 individuals, 75% of the savants had a common underlying ASD diagnosis (Treffert and Rebedew 2015). Savant skills exemplify the heterogeneity of the autism spectrum, and are associated with many myths and misconceptions that have recently been debunked. For example, not all savants are autistic, and not all autistic persons are savants. Likewise, savant syndrome is not always associated with low IQ. In addition, despite initial reports that savants as a group are not very creative, more recent observations provide a different picture. One musical savant was able to play back Tchaikovsky’s First Piano concerto flawlessly after having heard it for the first time on TV. But in concerts performed later in life, the same individual incorporated not only replication, but improvisation into his performances by changing the pitch and tempo to produce variations on well-known pieces, and eventually began creating and composing entirely new musical pieces (Treffert 2014).

Adding to the confusion surrounding twice-exceptionality and cognitive divergence in ASD is the fact that the diagnostic criteria for the disorder are still evolving. For example, the term Asperger syndrome was included in DSM-4 in 1994 to delineate high-functioning autism, then was dropped in the DSM-5 iteration released in 2013, which subsumed Asperger syndrome under the ASD umbrella. This alternating terminology has made it particularly challenging to track the relevant literature on exceptional abilities in autism, which can present in both high-functioning autism and autism with intellectual disability. We begin by summarizing cognitive theories of exceptional ability in ASD and move on to review what is known regarding neural correlates of these abilities. We then discuss clinical and societal implications of this phenomenon, and close by suggesting future directions for this emerging line of research.

Theories and cognitive profile of exceptional abilities in autism

A number of theories have been put forth attempting to account for exceptional abilities within the context of broader inter-related theories of autism. A sampling of these theories and relevant empirical work is provided here. The three that are most relevant for our current discussion are the hyper-systemizing theory (Baron-Cohen and Lombardo 2017), the weak central coherence theory (Happe and Frith 2006), and the enhanced perceptual functioning theory (Mottron et al. 2006). We’ll briefly review these theories, highlighting empirical support where it exists.

Hyper-systemizing theory

Systemizing is the drive to analyze systems or construct systems, and has been hypothesized to provide an explanation for the link between autism and exceptional abilities (Baron-Cohen et al. 2009). The hyper-systemizing theory posits that people with autism are hyper-systemizers; individuals who are motivated to identify lawful regularites that govern the input-operation-output workings of a system. Hyper-systemizing is posited to potentially contribute to savant skills in the domains of calendrical calculation, mathematics, and music due to obsessive systemizing in that particular domain (Baron-Cohen and Lombardo 2017). The Systemizing Quotient is a self-report questionnaire designed to measure this in an individual, and includes questions such as “I am fascinated by how machines work” and “In maths, I am intrigued by the rules and patterns governing numbers” (Baron-Cohen et al. 2003). The hyper-systemizing theory posits that attention to detail in autism functions to achieve the goal of understanding any kind of system, and strong systemizing as seen in the disorder explains RRBs such as narrow interests and insistence on sameness (Baron-Cohen et al. 2009).

One study compared cognitive, perceptual, and behavioral profiles of autistic adults with savant skills (n =44), autistic adults without savant skills (n=36), and neurotypical individuals without autism or savant skills (n = 31). The authors found that those with savant skills had higher sensory sensitivity, obsessive behaviors, and more systemizing (Hughes et al. 2018).

Weak central coherence theory

Several theoretical accounts have focussed on the impact of detailed-focused cognitive styles (Happé and Vital 2009) - such as those associated with RRBs - as predispositions for the emergence of special skills and talents in autism. The weak central coherence theory of autism attempts to account for both deficits and strengths in perceptual processes, and refers to the phenomenon that diagnosed individuals show a bias for featural and local information, failing to extract the gist or “big picture”. This detail-focused cognitive style leads to potential superiority in local or detail-focused processing (Happe and Frith 2006). Early support for the weak central coherence theory as an explanation of islets of ability in autism came from the embedded figures test, which asks participants to place cut-out target shapes on top of hidden shapes, thereby assessing the ability to attend to perceptual details (Shah and Frith 1983) (Figure 1). More recent larger sample studies of embedded figures test performance have not found evidence for superior performance in children with ASD (White and Saldaña 2011).

Figure 1.

Cognitive theories accounting for exceptional abilities in autism. Hyper-systemizing (Simon Baron-Cohen and Lombardo 2017), weak central coherence (Happé and Vital 2009), and enhanced perceptual functioning (Mottron et al. 2006) are the theories of autism that have attempted to explain enhanced performance, or islets of ability in autism that tend to manifest in specific cognitive domains.

Enhanced perceptual functioning theory

Closely related to the central coherence theory is the enhanced perceptual functioning theory. Superior performance on visual search tasks has been noted in individuals with high-functioning autism across the lifespan. In these types of attention tasks, participants are asked to locate a target item embedded within an array of distractors (eg. local-global tasks where participants are instructed to attend to a specific feature of a stimulus). A recent review of this literature reported low to moderate effect sizes across studies investigating visual search superiority in autism, and noted that the advantage is not consistently found (Constable et al. 2020). Proposed cognitive mechanisms underlying superior search performance include enhanced perceptual discrimination (Kaldy et al. 2016) - the simultaneous discrimination of multiple visual stimuli (Shirama, Kato, and Kashino 2017) - and altered attentional processes (Keehn and Joseph 2016).

Mottron and colleagues first formulated this theory after observing an autistic individual with savant syndrome who favored local elements in perceptual tasks. The hypothesis is that the development of savant abilities requires an encounter with a perceptually defined class of units, a brain-behavior cycle, expertise effects, implicit learning, and generalization to new material (Mottron et al. 2006). Performance on Raven’s Progressive Matrices tests of intelligence and Block Design subtests within Wechsler Intelligence Scale often also reveal unique strengths in autism that are discrepant with verbal measures (Dawson et al. 2007).

How well do theories of autism account for exceptional abilities?

Despite these theoretical accounts, a review published in 2011 was able to identify only five empirical studies on twice-exceptional children with ASD in the prior 20 years (Foley Nicpon et al. 2011). A study of academic experiences of 59 twice-exceptional children with ASD (ages 5–17) reported that working memory and processing speed indices were significantly positively correlated with reading, mathematics, and written language achievement. The authors also noted that working memory and processing speed explained 61% of the variance in reading achievement, and fine motor skills predicted math achievement (Assouline, Foley Nicpon, and Dockery 2012).

Most of the studies to date were conducted on relatively small samples of twice-exceptional individuals with ASD. A larger study of 1470 children (4–18 years) observed that 46% of children with autism had a parent-reported talent or strength (referred to as ‘extraordinary talents’) in the areas of memory, reading, and computation. These autistic children showed unique cognitive profiles from those with the diagnosis with no reported extraordinary talents (Bal, Wilkinson, and Fok 2021). In an earlier study of 137 individuals with autism with a range of intellectual abilities, 28.5% of the sample met criteria for either a savant skill or an exceptional cognitive skill in the visuospatial and mathematical domains. Contrary to the theory that savant skills are associated with ritualistic behaviors and circumscribed interests (O’Connor and Hermelin 1991), this study did not find evidence of a relationship between severity of RRBs and savant abilities (Howlin et al. 2009).

Math and reading skills are a domain where exceptional abilities in ASD are often noted in a subset of individuals. While the majority of individuals with Asperger syndrome or high-functioning autism have average mathematical ability, some exhibit mathematical giftedness (Chiang and Lin 2007). In a study of 114 children with ASD, Chen and colleagues found evidence for a subgroup with poor math skills compared with reading skills and another with higher math skills compared with reading skills (Chen et al. 2019), again underscoring the heterogeneity that is so often observed in this population.

At this juncture, it would be premature to conclude that any of the major theories of autism outlined here will best account for exceptional abilities, given the mixed empirical support. For example, there is evidence for enhanced performance on perceptual tasks in individuals with autism who do not necessarily exhibit exceptional abilities, as described in the following section.

Neural basis of exceptional abilities in autism

If there are few empirical investigations of exceptional abilities in autism, there are even fewer studies examining the neural basis of these abilities. Of the few neuroimaging studies that exist, most are case reports of single individuals. One study reports the case of an individual (GW) with Asperger syndrome who presented with savant skills in the domains of art and calendar calculations (Wallace, Happé, and Giedd 2009). When comparing cortical thickness with an age-matched neurotypical group, GW exhibited thinner cortex in superior frontal gyri, medial prefrontal cortex, primary motor cortex, and middle temporal gyrus and thicker cortex in bilateral superior parietal areas that have been implicated in mathematical cognition (Dehaene et al. 2004). Another case study that used functional magnetic resonance imaging (fMRI) to compare calendar calculation strategies in a savant with Asperger syndrome and a self-taught mathematical prodigy found diverging patterns of neural activation in these two individuals. While the individual with Asperger syndrome showed widespread brain activation during calendar tasks, the math prodigy with no clinical diagnosis appeared to show more focal parietal patterns of activation (Fehr et al. 2011).

To assess empirical evidence in support of the enhanced perceptual functional model that attempts to account for superior visual search abilities in autism, a meta-analysis of 26 fMRI studies focused on face, object, and word processing. Across studies, they observed greater neural activity in temporal, occipital, and parietal regions in individuals with ASD compared with neurotypical controls, alongside lower task-related activity in frontal cortices (Figure 2). The authors suggest that autism may thus be characterized by enhanced neural resource allocation for brain regions involved in visual processing (Samson et al. 2012). While this study did not separate out individuals with enhanced ability per se, it does point to potential neural mechanisms that might support such abilities.

Figure 2.

A meta-analysis of fMRI studies revealed greater task-related activity in posterior brain areas for autistic individuals compared with neurotypical individuals across face (red), object (green), and word (blue) processing studies. Reprinted with permission from (Samson et al. 2012).

A magnetic resonance spectroscopy study also investigated superior search abilities and found that in children with ASD, greater concentration of the neurotransmitter gamma-aminobutyric acid (GABA) in the visual cortex was related to more efficient search strategies (Edmondson et al. 2020). This finding is in line with the hypothesis that ASD may result from atypically increased cortical excitation due to an imbalance of excitatory glutamatergic signaling and inhibitory GABAergic signaling - the E/I imbalance theory (Rubenstein and Merzenich 2003).

Superior math abilities in children with ASD have also been investigated using fMRI. The conclusion that posterior brain areas are over-recruited in ASD is generally supported by this line of work. A study of 18 children with high-functioning ASD showed that these children showed better numerical problem solving abilities and sophisticated strategies compared with typically developing (TD) children. Conventional univariate analyses did not reveal any significant group differences in brain activation during task performance. However, multivariate patterns in ventral temporal-occipital and posterior parietal cortices distinguished children with ASD from TD children. Further, activation patterns in ventral temporal brain areas that are typically activated during face processing were associated with numerical problem solving abilities in children with ASD but not TD children (Figure 3), suggesting unique neural utilization capabilities subserving mathematical abilities in the disorder (Iuculano et al. 2014).

Figure 3.

Brain regions predicting numerical problem-solving abilities in children with ASD overlap with canonical face processing regions. Reprinted with permission from (Iuculano et al. 2014).

Taken together, the scant literature on the neural basis of exceptional abilities in autism leaves much to be desired. Limited sample sizes and the lack of an explicit focus on cognitive strengths in autism have contributed to this gap. The findings from the neuroimaging studies reviewed in this section thus do not necessarily generalize to twice-exceptional individuals with ASD, but provide direction for how such studies might be undertaken.

Clinical and societal implications

Individuals with ASD who can be characterized as twice-exceptional exhibit exceptional giftedness, but still experience exceptional challenges. Cain and colleagues analyzed a large longitudinal dataset collected over a 6 year period to describe academic trajectories of twice-exceptional children with autism. Children were between 3–6 years of age at the beginning of the study and 8–11 years of age at the end. Children who scored at or above the 90th percentile on any subtest of the Woodcock-Johnson III Tests of Achievement and/or were qualified for the gifted and talented program at their school were categorized as “gifted”. Twenty one percent of the children with ASD in this sample were gifted according to the above definition. These gifted children improved over time relative to non-gifted ASD children on academic outcomes. The gifted children with ASD also benefited disproportionately from mental health services (Cain, Kaboski, and Gilger 2019).

As twice-exceptional children enter adolescence and navigate transitions to adulthood, they face additional unique challenges. Interviews with 40 academically talented individuals with ASD who were enrolled in competitive colleges revealed that they generally participated in challenging courses, interest-based extra-curricular activities, and other advanced educational experiences. A quarter of the sample reported experiencing challenges with the dual identification of both having ASD and being academically talented. Still, many of the interviewees reported attaining a good understanding of their strengths and weaknesses during elementary school years (Reis, Gelbar, and Madaus 2021). This study highlights the positive contributions to society that twice-exceptional individuals with ASD can make when appropriately supported and encouraged.

Individuals diagnosed with ASD generally have poorer outcomes in transitioning to independent living compared with those with learning disabilities, intellectual disabilities, or emotional disturbances. Young adults with ASD are the least likely of these disability groups to have ever lived independently since leaving high school (Anderson et al. 2014). Similarly grim statistics highlight the employment gap for autistic adults; only 58% of young adults on the autism spectrum work for pay outside the home between high school and their early 20s (Roux 2015). The statistics surrounding those who are twice-exceptional are more difficult to ascertain.

Twice-exceptional children with autism can be misunderstood and thus are often under-served in terms of their social and emotional needs. Accommodations that parents, clinicians, and educators can engage in to aid twice-exceptional children with ASD academically include allowing them to choose specific reading materials in their areas of interest, avoiding timed tasks, and repeating information about directions for assignments. Guidelines for enhancing social skills and addressing language and communication difficulties that are specifically tailored to help twice-exceptional children are also available (Assouline et al. 2008).

Future directions

Autism is sometimes linked with savant skills or giftedness. Despite public fascination surrounding this phenomenon, exceptional abilities in autism do not necessarily translate to functional skills for the individuals who exhibit them. Very few individuals succeed in using their skills to find permanent employment or greater social integration (Howlin et al. 2009). As we have seen, twice-exceptional individuals with ASD often have unique skills that enable them to potentially make significant contributions to the workforce, while at the same time facing unique challenges during the transition to independent living due to a lack of appropriately tailored services (Assouline et al. 2008). A priority for future research is identifying predictors of, and contributors to, successful social, academic, and occupational trajectories for these individuals.

There is so much that is unknown regarding the neural basis of exceptional abilities in autism at present, with many theories but few empirical investigations. With the exception of a handful of case studies that have been conducted to date, the neural correlates of cognitive divergence in autism are unspecified. Without dedicated funding for these efforts, the mystery of the neural architecture supporting this phenomenon will remain unsolved. While autism research has historically focused on understanding social and cognitive difficulties that diagnosed individuals experience, a greater emphasis on strengths and islands of ability will ultimately be required to fully characterize heterogeneity in this increasingly prevalent neurodevelopmental disorder.