Synesthesia and Sensory Diversity: The Life and Lab of Julia Simner

In this Conversation with Julia Simner, we explore synesthesia, misophonia, and other sensory differences that shape how people perceive the world. Simner discusses how synesthesia sits on a continuum, the brain connectivity patterns behind it, and landmark research that reveals how common sensory differences actually are. She also shares pivotal life moments that steered her into this field, including a scholarship that redirected her from chemistry to psycholinguistics, and a notable case study of a man who tastes words. The discussion covers how childhood experiences, diagnosis, and society’s labeling influence our understanding of sensory experiences, and ends with a call to celebrate human diversity in perception.

Introduction: Seeing the World Through Senses

The interview introduces Julia Simner, a neuropsychologist who studies synesthesia and other multisensory experiences. Simner explains that synesthesia is a merging of senses, a phenomenon that appears in many forms and across a broad population. The host and Simner discuss how researchers approach synesthesia clinically, including informal screening questions and structured tests that probe color associations with letters and numbers, descriptive richness, and consistency across time.

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

Pathways Into the Field: Serendipity and Shifts

The conversation then traces Simner’s winding career path, from a planned chemist to a linguist, then to psychology. A Sorbonne scholarship at sixteen redirected her toward French, a near miss at Oxford reshaped her trajectory, and a pivotal master's in Canada pulled her into psycholinguistics and ultimately into synesthesia research. These moments illustrate how chance intersections can steer a life toward science with lasting impact.

Case Studies: Words, Tastes, and Language

Simner discusses her early exposure to synesthesia through patient casework, notably a man who tastes words. She explains that tastes can be triggered by language sounds, with phonemes shaping taste experiences. The exploration reveals that synesthetic associations often begin in childhood, are linked to diet, and gradually generalize to words with similar phonetic properties. The interview highlights how linguistic analysis uncovers the systematic structure underlying synesthetic pairings, suggesting a deep link between language sound patterns and perceptual experience.

"The flavours that flood the mouth in synesthesia are significantly tied, particularly to childhood diet." - Julia Simner

Brain Mechanisms and Theories: How the Mind Becomes Multisensory

The dialogue shifts to brain-level explanations. Simner describes how imaging shows heightened cross-activation between sensory regions in synesthetes and a brain network that functions more like a railway map than a simple, linear system. She discusses competing developmental theories, including neonatal hyperconnectivity and pruning that may leave behind cross-sensory links, and an evolutionary perspective that sees sensory diversity as potentially advantageous for memory and perception. The conversation emphasizes that multiple theories can be complementary rather than mutually exclusive.

"The brain works a little like a railway map, with hubs and bypass routes connecting different regions." - Julia Simner

Prevalence, Inheritance, and Family Ties

Her research broadened the view of how common sensory differences are, revealing that synesthesia affects at least about 4.4% of the population, with roughly equal numbers of men and women. Simner notes that sensory experiences often run in families and that many sensory traits co-occur with conditions such as autism and a high degree of sensory sensitivity, which she treats as a core mediator in many cases. This segment also touches on a personal note: her mother’s own synesthetic profile and the ways family history informs scientific hypotheses about inheritance.

"The prevalence is actually at least 4.4% with an equal ratio of men and women." - Julia Simner

Misophonia, Personal Challenge, and Real-World Impact

The discussion turns to misophonia, a condition characterized by distressing reactions to specific sounds. Simner explains how research evolved from curiosity to clinical relevance, including the creation of diagnostic tools for childhood misophonia and collaborations to ensure quiet testing environments for exams. A parallel story about her son’s battle with diabetes illustrates how personal experience can drive scientific and practical breakthroughs, such as life-changing medical devices and supportive interventions for families facing similar challenges.

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

A Map of Sensory Diversity: The Periodic Table Concept

Towards the end, Simner and her team describe the sensory-diversity network—a three-dimensional map organizing sensory differences by sense, phenomenology, and trigger. They illustrate how this framework can reveal gaps and predict new areas of inquiry, such as communities around interoception like cardiophilia, where people derive pleasure from sensing their heartbeat. The map emphasizes not pathologizing differences but recognizing the spectrum of human perception and its potential benefits for creativity, memory, and cognition.

"We created a periodic table of sensory differences to link diverse populations and connect fields that study them." - Julia Simner

Conclusion: A Call to Celebrate Sensory Diversity

The conversation closes on a thoughtful note about labeling versus understanding and celebrating differences. Simner argues for a balanced view that respects individual experiences while seeking ways to support those whose sensory differences are distressing or disruptive. The episode invites listeners to consider how appreciating diverse ways of experiencing the world can enrich science, education, and art alike.

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