Synaesthesia: Part 1 - Experiencing the World in Technicolour (and More!) - A Neurodiversity Deep Dive

Hello and welcome to this ASD Consulting blog! Have you ever heard someone describe "seeing" music as colours, or "tasting" words? While it might sound like something out of a science fiction novel, for a significant number of people, this is their everyday reality. This phenomenon is called synaesthesia, and it's a remarkable example of the incredible diversity that exists within human neurology – a true facet of neurodiversity. It's not a disorder, but rather a fundamentally different, and often beautiful, way of experiencing the world in Technicolour.

So, What Exactly is Synaesthesia?

At its heart, synaesthesia is a neurological trait where the stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. Think of your senses and cognitive functions as different channels in your brain. For most people (neurotypicals), these channels operate largely separately. But for a synaesthete, there are unique, automatic cross-connections between these channels.

There are many different forms of synaesthesia, often described by the two pathways involved. Some common examples include:

• Grapheme-Color Synaesthesia: Seeing individual letters or numbers as inherently coloured. 'A' might always be red, 'B' blue, and so on.

• Chromesthesia (Sound-to-Colour Synaesthesia): Experiencing sounds, like music, voices, or everyday noises, as visual perceptions of colour, shape, or texture.

• Lexical-Gustatory Synaesthesia: Tasting specific flavours when hearing or reading words. The word "street" might taste like lemons, for instance.

• Spatial Sequence Synaesthesia: Seeing numerical sequences (like dates or numbers) or ordered sequences (like the alphabet or months of the year) as occupying specific points in space.

These experiences are consistent for the individual synaesthete – if 'A' is red for you, it will always be red. They are also involuntary; it's not something the person actively does, but rather something that happens to them.

The Neuroscience Behind the Blend: From a neuroscientific perspective, synaesthesia is thought to arise from increased connectivity between different areas of the brain that are typically more segregated in neurotypical individuals. Imagine the brain as a city with different districts responsible for different functions (like a district for processing sound, and another for processing colour). In the neurotypical brain, the roads between these districts might be less direct. In the synaesthetic brain, there might be more direct highways or additional smaller roads connecting these districts, allowing information to flow between them in a unique way.

Research using brain imaging techniques has provided evidence for this increased connectivity. While the exact mechanisms are still being explored, it's clear that the brains of synaesthetes are wired differently, leading to their unique sensory experiences.

How is Synaesthesia Recognised?

Often, individuals with synaesthesia grow up assuming everyone experiences the world the same way they do. It might only be through conversations with others, reading about it, or encountering the term that they realise their perceptions are different. There isn't a single formal diagnostic test like there might be for some medical conditions, but researchers use tests that check for the consistency of the synaesthetic associations over time.

For many, recognising their synaesthesia is a process of self-discovery and understanding their own unique sensory landscape. It can be a moment of clarity that explains lifelong experiences they may have found difficult to articulate before. Formal "diagnosis" or recognition by a professional isn't always sought or needed, depending on the individual's circumstances and how their synaesthesia impacts their life. The important part is understanding and validating this aspect of one's neurological makeup.

Prevalence and Connections to Other Neurodiversities: While not everyone has synaesthesia, it's also not exceedingly rare. Estimates of its prevalence vary, but studies suggest it could be present in around 2-4% of the population.

Interestingly, research has shown that synaesthesia appears to be more common in individuals who are also on the autism spectrum. This observation is leading to further research into potential shared underlying neurological features between different forms of neurodivergence, such as differences in sensory processing or local versus global brain connectivity. However, it's crucial to understand that having synaesthesia does not mean someone is autistic, or vice versa. They are distinct traits, though they can sometimes co-occur. Synaesthesia is its own unique expression of neurodiversity.

A Unique Way to Experience Reality: Synaesthesia offers a captivating glimpse into the diverse ways human brains can perceive reality. It highlights that there isn't one single "normal" way to experience the senses, but rather a spectrum of possibilities.

In the next part of this series, we'll delve into what it's like to live with synaesthesia day-to-day, exploring both the joys and the potential challenges, and discussing how individuals can navigate their multisensory world to live a full and thriving life.