Summary: New research indicates that people with synaesthesia and those on the autism spectrum share heightened sensory sensitivity as a core feature.
Source: University of Sussex.
Researchers identify concrete sensory links between autism and synaesthesia
Psychologists at the University of Sussex, working with colleagues at the University of Cambridge, have identified clear sensory connections between autism spectrum conditions (ASC) and synaesthesia. Published in the journal Scientific Reports, the study shows both groups report similar atypical sensory sensitivity despite marked differences in social communication and other classic autism traits.
Previous studies detected a higher-than-expected co-occurrence of synaesthesia in autistic populations. This new research goes further by clarifying which symptoms are shared and how they overlap: rather than social or communicative difficulties, the overlap is primarily sensory.
Synaesthesia is commonly described as a “mixing of the senses,” where stimuli such as sounds, words or music automatically evoke additional sensory experiences (for example, colours or tastes). Autism, by contrast, is defined chiefly by challenges in social understanding and communication. The Sussex–Cambridge study demonstrates that many people in both groups experience strong sensory responses—both hypersensitivity (aversion to certain sounds, sights or touches or heightened sensory discrimination) and hyposensitivity (a diminished response to stimuli or a drive to stimulate the senses).
The research team administered the Glasgow Sensory Questionnaire (GSQ) and additional measures to groups of synaesthetes, autistic participants, and controls. Both synaesthesia and autism groups scored higher on sensory atypicalities than controls, with a large effect size. The pattern of heightened sensitivity extended across multiple senses and included both increased hyper- and hypo-sensitivities.
Autism-Spectrum Quotient (AQ) scores were higher among synaesthetes, particularly on the attention-to-detail subscale, which placed many synaesthetes within the autistic range for that trait. However, synaesthetes generally did not report the communication and social difficulties that define autism diagnostically, indicating the shared profile is sensory rather than social.
The study was led by Professor Jamie Ward, Professor of Cognitive Neuroscience and Co-Director of the Sussex Neuroscience group, with Professor Julia Simner from Sussex Psychology and Professor Simon Baron-Cohen, Director of the Autism Research Centre at the University of Cambridge.
Professor Ward commented: “Synaesthesia has often been framed as a positive or benign difference, while autism is frequently seen through a more clinical lens. Our findings suggest substantial overlap in sensory processing between the two. Understanding these shared sensory traits may help explain some positive aspects of autism, such as savant skills, and could reveal further neurological connections.”
The research group is preparing a follow-up paper that examines savant-like talents in people with autism and how these abilities may relate to synaesthesia. Early results reinforce the initial findings: synaesthesia is especially prevalent among autistic individuals who display prodigious talents—exceptional abilities in areas such as arithmetic, memory, or visual art.
Professor Ward added: “Some theories propose that heightened sensory sensitivity underpins social and communicative challenges in autism. Our results highlight the importance of treating sensory differences as a central, shared dimension between autism and synaesthesia. Future work will continue to explore how perceptual, cognitive, and social traits interact across these populations.”
The related paper examining synaesthesia and savantism is titled “Is synaesthesia more prevalent in autism spectrum conditions? Only where there is prodigious talent” and is scheduled for publication in the journal Multisensory Research. The primary study, “Atypical sensory sensitivity as a shared feature between synaesthesia and autism,” appeared as an open-access article in Scientific Reports on 7 March 2017.
Source: Ellin Kavanagh, University of Sussex. Image credit: Ben Husmann. Original research: “Atypical sensory sensitivity as a shared feature between synaesthesia and autism” by Jamie Ward, Claire Hoadley, James E. A. Hughes, Paula Smith, Carrie Allison, Simon Baron-Cohen & Julia Simner, Scientific Reports, published online 7 March 2017. doi:10.1038/srep41155
Atypical sensory sensitivity as a shared feature between synaesthesia and autism
Several studies have suggested a relationship between synaesthesia and autism, but the nature of that relationship has been unclear. This study investigated whether atypical sensory sensitivity—either hypersensitivity (aversion to certain sounds, touch, or light, or superior sensory discrimination) or hyposensitivity (reduced responsiveness or a desire to self-stimulate)—is a common feature of both conditions. Using the Glasgow Sensory Questionnaire and other measures, synaesthetes and people with autism spectrum conditions reported increased sensory sensitivity compared with controls, with a large effect size. Both groups showed similar patterns of hyper- and hypo-sensitivities across senses. Synaesthetes also scored higher on the Autism-Spectrum Quotient, particularly on attention to detail. An online Pattern Glare Test corroborated increased aversive visual sensitivity among synaesthetes. The authors conclude that atypical sensory sensitivity is an important shared characteristic of autism and synaesthesia.
“Atypical sensory sensitivity as a shared feature between synaesthesia and autism,” Jamie Ward et al., Scientific Reports, published online 7 March 2017. doi:10.1038/srep41155