For millennia, human experience has been defined by five senses. However, advances in neuroscience and technology may soon provide a much broader perspective. What counts as feeling in the first place is often not clearly defined. Sight, hearing, taste, smell and touch are part of the traditional five senses. But our sense of balance and the ability to track our own body movements (proprioception) are also important. Our temperature and pain monitoring systems also qualify as independent senses.
These feelings are also not as solidly reliable as we used to think. About 4.4% of the population experiences synesthesia - when stimulation of one sense organ simultaneously produces sensations in another. This leads people to perceive colors when they hear sounds, or to associate shapes with certain tastes, which demonstrates the possible fluidity of our feelings.
In recent years, scientists have taken advantage of this fluidity to develop workarounds for those who have lost one of their senses. The breakthrough work of American neurologist Paul Bach-u-Rit in the 1960s showed the plasticity of the human brain. He created a chair that translated the video stream into vibrations by 400 small touchpads pressed against a person's back. This allowed blind patients to distinguish between faces, objects, and shadows.
As Bach-u-Rita himself said in 2003, “we do not see with our eyes; we see with our brain. Armed with this principle, he and his laboratory developed a series of sensory manipulation techniques. In 1990, their work led to the creation of the Tongue Display Unit, which displayed tactile patterns on the tongue, helping the blind to see and restore a sense of balance.
Similar principles today are helping to rewire neural pathways by allowing visual scenes to be "heard" or sounds "felt". The vOICe smart glasses, created by Dutch engineer Peter Meyer, convert pixels from a video stream into sound, translating brightness and vertical position into height and volume.
The VEST, developed by David Eagleman at Baylor College of Medicine, is a vest that converts sound into vibrations that the user's brain can learn to interpret as individual sounds. While VEST should help the deaf, its API is open source and can be used to read Twitter feed, stock market data, or forecast the weather.
This opens up a tempting opportunity not only to remake, but also to expand our sensory experience with inputs previously inaccessible to humans. What began as a solution to medical problems has evolved into the philosophy of transhumanism, which seeks, through science and technology, to provide us with deliverance from our current physical and mental limitations.
Artist and cyborg Neil Harbisson is a living example of this trend. Born with a form of color blindness, he saw the world in shades of gray until he got an antenna with a camera implanted right into his brain that converts colors into audible vibrations. The vibration frequency depends on the hue of the visual scene. Now, he says, he is experiencing synesthesia: he hears pictures, can describe colors with certain sounds, and perceives infrared and ultraviolet light.
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The latter property is especially important - these frequencies lie outside the normal visible spectrum of a person. He was not the only one to push the boundaries of human sensory experience. University of Reading professor Kevin Warwick has embedded an array of electrodes directly into his nervous system to demonstrate that a robotic arm can be controlled by the brain. In a subsequent experiment, he used the same implant connected to ultrasonic sensors to hear the ultrasound.
The animal kingdom is full of inspiration for aspiring transhumanists looking for new ways to perceive the world. Many snakes can see in the infrared spectrum, that is, they have a form of thermal vision; some fish species can detect electric fields; birds and insects can tap into the earth's magnetic fields.
Experiments on rats have shown that these perceptual abilities are not species specific. By connecting detectors to the rodents' brains, neuroscientists at Duke University allowed them to "feel" and "see" in the infrared range. Another group from the University of Tokyo connected a geomagnetic compass to the visual cortex of blind rats, which allowed them to navigate the maze like sighted people.
While it will probably take some time before scientists dare to conduct such experiments on humans, “biohacker” or “grinder” societies take the liberty, like Harbisson and Warwick, and modify their bodies during practical transhumanism.
Various teams are experimenting with implanting magnets in their fingertips and seismographs in their elbows, allowing them to activate various devices or sense earthquakes.
It is gradually becoming more obvious that the sphere of human perception is wider than many might think. Very soon, amazing perspectives of perception will open up to us.