Life Scientific: Mapping the Senses with Julia Simner – Synesthesia, Misophonia and Sensory Diversity

In this edition of The Life Scientific, Jim talks with Julia Simner, a neuropsychologist at the University of Sussex, about synesthesia and the broader landscape of sensory differences. They explore informal tests for synesthesia, including color associations for letters and numbers, the O/I eye test, descriptive richness, and consistency across time. Simner describes how childhood experiences and brain wiring shape these senses, the links to autism and sensory sensitivity, and how her career arc—from a Sorbonne scholarship to psycholinguistics in Canada—led to breakthroughs in synesthesia research. The interview also covers misophonia, the idea of mapping sensory differences on a periodic table, practical outcomes like quiet exam rooms for misophonia, and the hopeful perspective that we can celebrate sensory diversity rather than pathologize it.

Introduction: synesthesia and multisensory perception

The episode opens with a lay-friendly introduction to synesthesia, describing how words and sounds can evoke colors, tastes, and textures in some people. Julia Simner explains that her research has shown synesthetic experiences lie on a continuum rather than a simple yes/no condition, and she outlines the four key tests used in diagnosing synesthesia in the lab: color associations for letters and numbers, a descriptive richness test, and a consistency test across repeated tasks. The segment sets up the central idea that synesthesia reveals how the brain can blend sensory modalities in systematic ways, offering a window into the architecture of perception.

"It’s definitely a continuum because even people without synesthesia can have synesthesia-like experiences." - Julia Simner

From serendipity to science: a life swerved toward synesthesia research

Simner recounts her unlikely career arc, tracing a path from chemistry to French studies in Paris, a near miss at Oxford, and a year-later restart that led to a master’s in Canada and a pivot into psychology. A pivotal collaboration with Jamie Ward brought her to synesthesia through the case of James Wannerton, a man who “tastes words”. The discussion highlights how a chance encounter and interdisciplinary training can redefine a scientist’s focus and open new doors for understanding unusual perceptual traits.

"You could say the brain's a lot like a railway map." - Julia Simner

Brain networks, development, and the prevalence of synesthesia

The conversation moves to neuroscience findings that underpin synesthesia, including brain-imaging evidence showing color regions activated during reading for synesthetes. Simner describes a railway-map analogy for how the brain’s hubs and connections differ in synesthetes, sometimes bypassing typical pathways. The episode also covers prevalence research that unveiled synesthesia in at least 4.4% of people, with a roughly equal male/female distribution, reframing the trait from rarity to a measurable sensory variation. The discussion touches on childhood development, with sensory taste experiences crystallizing in early years and expanding from primary tastes to broader phoneme-based associations.

"The brain works a little like a railway map." - Julia Simner

Misophonia, autism links and the periodic table of sensory differences

The interview shifts to Simner’s work on misophonia, a condition characterized by distressing reactions to specific sounds. She explains how misophonia research gained traction through philanthropic support and how her personal life intersected with science when her son’s health crisis (diabetes) highlighted the real-world impact of sensory sensitivity. This led to the creation of a diagnostic for childhood misophonia and to practical adaptations, such as quiet rooms for exams. Simner and colleague Louisa Rinaldi developed a catalog—a three-dimensional periodic-table-like map of sensory differences that links senses, feelings, and triggers, revealing gaps that point to previously unknown populations, such as those who derive pleasure from certain internal sensations (cardiophilia).

"We created the very first diagnostic, for example, for childhood misophonia." - Julia Simner

Towards a language for sensory diversity: labelling, empathy and the future

Concluding sections emphasize that while labeling can help individuals understand themselves and access support, the goal is not to pathologize difference but to celebrate and integrate sensory diversity into education, culture, and science. Simner discusses outreach and arts programs that showcase how diverse sensory experiences enrich creativity and understanding. She also reflects on family dynamics, inheritance patterns, and the idea that while misophonia is a disorder by some definitions, other sensory traits like synesthesia and aphantasia are sensory phenomenology rather than pathologies. The talk closes with an optimistic view of a future where people map and celebrate their sensory profiles, contributing to a broader, more inclusive view of human perception.

"Knowing yourself is very important, but also being able to celebrate those differences." - Julia Simner