What would it be like to see in Bluetooth?

When I cycle on my indoor trainer, I listen to music through Bluetooth headphones and data from the trainer is sent by Bluetooth from the trainer to my phone. Bluetooth is just a form of radio transmission, and radio waves are, fundamentally, the same sort of thing as visible light. As I began my workout this morning, I was struck by how the room would soon be awash in invisible light waves. What would it be like to see them?

I suppose a natural first reaction is to imagine my phone glowing from its transmitted audio signal and my trainer glowing from its transmitted power and cadence data. The idea would be that, if you could see in Bluetooth, as you looked at transmitting devices they would appear to you to glow, akin perhaps to a neon sign, or something like that.

That idea might make sense if we were merely sensitive to radio waves in the Bluetooth range. We might imagine that our eyes had additional proteins, receptive to such photons. In that case, our visual system would detect the emission of Bluetooth waves from our devices. Assuming these proteins were part of our visual system, it would be reasonable to expect us to experience Bluetooth similar to how we experience other sources of light—e.g., perhaps as a glow.

The trouble with this idea is that it doesn’t take into account how perception involves more than merely being sensitive to a stimulus. Perception involves the decoding of information in a stimulus. The experience of looking at a bright light bulb and seeing its glow is not a representative example of visual experience. A better example would be what it’s like as you look around a new room you just entered. As you do so, your visual experience isn’t of the glow of lights, but instead is filled with the layout the room, the objects in it, and their visible qualities, such as color and shape. In fact, in this case, unless you are particularly attuned to the presence of light artifacts like shadows or there happens to be an attention-grabbing source of light, when you look around a room you’re likely to not notice light itself at all.

This example brings to the front a central feature of perceptual experience: its transparency. We perceive through intermediary information-carrying signals, such as light, sound waves, mechanical deformation, or chemical reactions. However, when we successfully decode these signals, the signal, or medium, itself falls out of consciousness. As I look around the room now, my visual experience is mediated by a sea of light waves, but those waves remain largely out of my visual experience. Instead, I experience the things in the room because my brain has decoded those things out of the light waves.

So, “seeing in Bluetooth” would involve more than a mere sensitivity to light in the Bluetooth range; it would involve an ability by the brain to decode the information carried by Bluetooth signals. Let’s set aside the question of whether, or how, that would be physically possible for a brain built like ours. Assume we could do it. The lesson from the above example is that our “Bluetooth experiences” would be largely characterized by the information they conveyed to us. Bluetooth encodings are very different from most sensory encodings, insofar as they are highly abstract. For example, the “code” of normal visible light is (to a first approximation) the geometry of light waves relative to our moving bodies. In contrast, Bluetooth encodes in a digital string of on-off signals. It operates through many layers of different possible encodings, allowing signals about things as different as music and training data to be sent.

Thus, a reasonable first guess is that, if I could see in Bluetooth, I wouldn’t experience the Bluetooth waves as a glow from my phone and trainer, or experience them at all; I would, instead, experience what they represent: the music and the training data. Set aside the music for a moment. That will raise a second important point. For now, consider the training data, such as my power and cadence numbers. If you write numbers down on a piece of paper and hold it in my line of sight, I see the numbers. Would my Bluetooth experience of the training data be similar? There is one important way in which the two would differ. The normal visible light reflecting off the paper carries with it spatial information about the position of the paper and the marks on it, along with information about their shape and color. In contrast, the bluetooth waves carrying my power and training data carry no spatial information. While there is spatial information in the waves about their source (the source of the waves), there is no information in the waves about the spatial location of the numbers. There is no reason to expect someone seeing in Bluetooth to see the training data coming from my trainer as itself located in the trainer. For that matter, there’s no reason to expect a “Bluetooth seer” to see the data as located anywhere in the space around them, or as being in a font or any sort of type with shape or color. There are, of course, encoding features analogous to a font which might be experienced, such as the digital on-off spikes encoding the numbers.

These considerations suggest that you would experience the trainer data aspatially, i.e. without experiencing it as located anywhere, and experience it in a temporally extended string of digital signals, perhaps not too dissimilar from listening to numbers in Morse code. Before returning to the music, another aspect of the trainer data is worth mentioning. If you are the rider on the trainer, the power and cadence numbers are not independent of your bodily motion or effort. As you pedal harder and faster, the numbers increase. This suggests that there might be some sort of multimodal binding with your kinesthetic experience. The Bluetooth waves from the trainer may become, for the rider, part of their experience of their body and their effort, similar to how the rider experiences their body through proprioception and their effort through pain.

What about music? Given the aspatiality just mentioned, and the comparison to listening to Morse code, you might think that Bluetooth experience of music would more or less be like normal auditory experience of music. While that might end up being the case, we have to consider a second fundamental feature of perception: its modality. Although it’s true that perception is largely transparent, with the intermediary signals falling out of consciousness, perceptual experience is colored by the sensory apparatus (or modality) through which we gain it. For example, you can experience the circular shape of a glass top both by seeing it and by feeling it. However, visual experience of the glass top’s shape is very different from haptic experience of that shape. So, although the same song could be conveyed through both Bluetooth waves and sound waves, it’s not obvious whether your experience would be the same in both cases.

Well, what makes seeing and feeling the shape of a glass top different? The modalities themselves lead to different experiences. In vision, you see not only the shape, but also the color. In touch, there is no color. In vision, the shape is presented all at once. In touch, it’s discovered through sensory exploration. In vision, seeing the shape depends on moving your eyes around the shape. In touch, feeling the shape depends on moving your hands around the glass top.

Are there analogous differences which would distinguish hearing a song from “Bluetooth-seeing” it? An obvious difference is the sense organ. You’d hear the song through your cochlea. You’d “see” it through special low-frequency photoreceptors in your eyes. Still, it’s not immediately obvious that different sensory organs necessarily lead to differences in experience. For example, eyes and hands lead to different experiences of shape, but seemingly because eyes can capture shape in a glance, while hands require time to explore.

Beyond the different sensory organs, differences are harder to spot. Both cases involve decoding a temporal string of information about pitch and sound amplitude. In the case of audition, you decode it directly from the sound waves themselves. In Bluetooth-seeing, you decode that information through a digital string of numbers. Perhaps that would matter—perhaps Bluetooth-seeing a song would be like a very experienced Morse-code operator hearing a string of speech in Morse code. Still, it’s unlikely the experience would be impoverished compared to hearing the song through normal audition. After all, the Bluetooth signal carries all the auditory information that’s ultimately delivered to the ears.

In summary, if you could directly perceive through Bluetooth, without mediating devices like wireless headphones or a phone screen, your experiences would likely not consist of seeing devices glow with radiowaves, not anymore than normal visual experiences consist of seeing the objects around you glow of light. Instead, the experiences would reflect the content of the information carried in the signals. As most of this information lacks the kind of spatial information characteristic of normal vision, these Bluetooth experiences would be mostly aspatial. Training data, music, emails, texts, or whatever else was carried by the signal might be experienced as having no physical location at all, perhaps as simply appearing “in your head” or “in your mind’s eye”. If the information was correlated with other sensory information, such as training data is with body movement, the experiences would likely be integrated together into an enriched overall experience. The digital presentation of the data would also likely affect the character of your Bluetooth experiences, perhaps making them akin to listening to Morse code.