One problem that crops up repeatedly in NLP is imprecision in the meaning of a word, creating an ambiguity about what kind of sensory experience a word refers to. Since most NLP works directly with changing sensory experience, it’s crucial to know what that is. The word “synesthesia” has been used in NLP for two very different kinds of experience, and this often causes confusion — whether or not that confusion is noticed. Below is an online definition of what the wider world means by the word synesthesia:

Synesthesia is a condition in which one sense (for example, hearing) is simultaneously perceived as if by one or more additional senses such as sight. Another form of synesthesia joins objects such as letters, shapes, numbers or people’s names with a sensory perception such as smell, color or flavor. The word synesthesia comes from two Greek words, syn (together) and aisthesis (perception). Therefore, synesthesia literally means ‘joined perception.’ ”

I want to point out three crucial criteria embedded in this quote: two (or more) sensory perceptions are joined simultaneously, in the same location in space and time. When someone sees a number in a particular color, they see a colored number — they don’t see a number adjacent to a swatch of color, or a number followed by a color, or a color followed by a number.

Synesthesia is often described as something rare and unusual, and it’s true that seeing letters or numbers in color is uncommon. Years ago when Connirae and I were investigating different spelling strategies in great detail, we found one woman who saw each letter of the alphabet in a specific individual color. When she spelled a word, she knew it was correct if all the letters changed to one color! Although this was a complex way of spelling words, and I wouldn’t recommend it over the “good spelling strategy” discovered in the early days of NLP, it did work for her.

Another aspect of synesthesia is that while it may seem unusual to those who don’t experience it, I have never heard of it being a problem for those who do. It is fairly common among “autistic savants” but it isn’t a cause of their limitations. Rather it is always a useful part of some amazing skills that are far beyond what most of us can do, such as quickly noticing if a large number is prime or not, or multiplying two large numbers. I have never heard of anyone for whom a synesthesia was a significant problem; rather it is an interesting embellishment of experience, and it is often credited with contributing to creativity. Here is a short TED talk by a synesthete; search online for “synesthesia savant” for other descriptions.

Actually we all experience synesthesia in ways that are so commonplace that it’s easy to overlook, and not realize that it is fundamentally the same process. As I type these words, the feeling in my fingers occurs at the same time — and in the same location — as the sight of my fingers moving on the keys, and the clicking sound of the keys. The same is true if I close my eyes and imagine typing — I see and feel my fingers moving on the keys, and hear the clicking sound that the keys make.

This is only an example of how our brains integrate the information coming from the different senses into a single coherent experience.

Imagine how weird and disconcerting it would be if those three different perceptions occurred in different locations and at different times! The feedback information from each sense would be out of synchrony with the others, making it difficult to learn even the simplest of motions, like bringing a glass to my lips to take a drink.



When someone has a representation in only one modality, an early basic NLP intervention is to overlap from that modality to others, in order to add information from other senses. “When you hear those words in that tonality, what image comes to your mind?” “When you see that image, what sounds can you hear?” That kind of question is a deliberate instruction to elicit synesthesia in order to enrich someone’s experience by accessing relevant useful information that they may be ignoring. An image of a future event may look wonderful, but when you add in sounds and/or tactile kinesthetic feelings, it may be much less desirable. With more information, we always make decisions that are more accurate and balanced predictors of future satisfaction.

In everyday conversation we often speak of a sharp sound, a sour smell, a sweet spot, a flat color, or a loud shirt. While some of these expressions may be only metaphoric, often they indicate synesthesia that is below awareness, or on the edge of what we usually notice in our internal experience. For instance, when I hear music or voices, I always have a visual experience of abstract transparent 3-D shapes moving from left to right. Like any other skill, it has advantages and drawbacks. I have always preferred simpler melodies or small ensembles, because it is easier to visualize a smaller number of sounds. When there are too many sounds, as with a large orchestra or a big band, my images become cluttered, tangled and unpleasant. I also have trouble understanding conversations in noisy rooms, and if I’m looking for an address in unfamiliar territory, I need to turn the car radio off or I begin to have symptoms of ADHD.

To summarize, the widely accepted meaning of synesthesia is to experience two or more sensory perceptions simultaneously in the same location in space. This is an enrichment of experience that is generally useful, and only very rarely a problem.


What is the other definition of synesthesia?

In Robert Dilts’ Encyclopedia of NLP the entry titled Synesthesia states:

“Sometimes various sensations become connected and overlapped so completely that it is not possible to easily distinguish one from the other in a causal relationship. Feeling deeply moved by a piece of music would be an example of this. The feeling cannot really be distinguished or separated from the sound of the music. The same could be said for the sense of fear or pleasure that people experience when they see certain types of images.”

These “hear-feel” or “see-feel” causal linkages were called “fuzzy functions” in the early days of NLP. They are very important to us — sometimes problematic; sometimes very useful — but they are radically different from the previous definition of synesthesia in several ways:

  1. The causal relationship mentioned by Dilts presupposes a passage of time between the cause and effect, so the joining of the two sensations is sequential rather than simultaneous — even if it is very rapid.
  2. The two sensations are in different locations in space. The sound or image causing the feeling is typically heard or seen in a location outside the body, while the feeling is felt inside the body, mostly along the midline of the chest and/or belly. Even when the sound is heard in the ears, or the image is seen inside the head, that is still a very different location than the emotional feeling of “feeling moved,” “pleasure,” or “fear.”
  3. Finally, the emotional feeling in response to the sound or image is an evaluative feeling that is very different from a perceptual tactile feeling in the skin or fingers. Tactile feelings provide information about what is touched — its size, temperature, pressure, texture, etc. In contrast, emotional feelings provide information about the values of the person having the feelings.

This distinction between tactile and evaluative feelings is clearest when we have an evaluative feeling in response to a tactile feeling. If you are enjoying a loving touch, you experience both tactile feelings in the skin and underlying tissue (pressure, temperature, etc.) and also your emotional experience of enjoyment along the midline. But if someone unwelcome touched you in exactly the same way, you would have a very different emotional response to the same set of tactile sensations.

These three differences point out how very different this second definition of synesthesia is from the more widely accepted one. When a NLPer says that a client has a “synesthesia,” they are almost always using this second meaning of the word. They are also usually talking about a synesthesia that a client complains about because the resulting feeling is unpleasant, or has problematic consequences.


Does this distinction matter?

Since any ambiguity can lead to confusion, it’s always useful to be very clear what a word means, especially when the wider world has a different meaning for it. One way to avoid the ambiguity of the word “synesthesia” is to simply not use it at all, which is what Connirae and I have done for many years. Most clients who seek personal change do so because of unpleasant evaluative feelings. Since usually they have little or no awareness of how those feelings are generated by mostly unconscious visual images, auditory sounds, tactile feelings — and/or less often, smell or taste — we don’t find any advantage in using a special word for it. Furthermore the word “synesthesia” is a nominalization that turns a process into a noun, and tends to distract and obscure the specific sensory experience it refers to. Keeping in mind that the emotional feeling is in response to a perception or memory in one or more of the sensory modalities helps us focus on adjusting those in order to change the resulting feeling.

But before making any such adjustments, it’s important to think about the “problem” feeling in a wider context of space and time, to be sure that a change is “ecological.” A “bad” feeling of shame or guilt may be very useful in motivating us to make apologies or amends to repair a relationship that was damaged by something we did, or failed to do. If this positive function is not incorporated into any change, it will be very difficult to make any change, and it isn’t likely to last.

The flip side of this is that some “good” feelings lead to destructive consequences, such as overeating, drug use, or other compulsive behavior. In those cases it can be useful to make adjustments that result in “bad” feelings that are more useful in the larger context of space and time.

25 April 2017: Also see the followup to this blog post, Small Scope Synesthesia.