HISTORY130 - Augmenting our Senses - Past and Future

I have previously written about human senses, delving into the science of how they work, and comparing them to animal senses.  See https://bobringreflections.blogspot.com/2024/02/science18-human-and-animal-senses.html. 

Sometimes our five basic senses: sight, hearing, smell, taste, and touch - don’t work as well as they should, e.g., poor eyesight or hearing.  After a short introduction, I will explore the history of corrective measures to bring our senses up to snuff, and what we can expect in the future.

 

As usual, I will list my principal sources at the end.

 

Introduction

The five basic human senses are our primary ways to perceive the world, using specialized organs (eyes, ears, nose, tongue, skin) to collect environmental information, send signals to the brain, and build our understanding and interaction with our surroundings, crucial for survival, learning, and daily function: 

 

·         Sight: Detected by the eyes, this sense allows us to see light, shapes, colors, and motion, helping us navigate and identify objects.

·         Hearing: Our ears detect sound waves, enabling us to hear music, voices, and warnings, crucial for communication and awareness.

·         Smell: The nose identifies airborne chemicals, letting us smell scents from a distance, which also influences our sense of taste.

·         Taste: The tongue detects chemicals in food, differentiating between sweet, sour, salty, bitter, and umami (pleasant, rich, savory taste found in foods like aged cheese, mushrooms, and soy sauce).  Taste is heavily linked with smell.

·        Touch: The skin perceives pressure, texture, temperature, and pain, providing vital information about our body's boundaries and surroundings. 

Each sense organ contains specialized cells that convert physical stimuli (like light or sound) into electrical signals. These signals travel through nerves to the brain, which processes and interprets them, creating our unified perception of the world. 

While these five sense are fundamental, humans have other senses, including balance, body position, pain, and others.

These five basic senses are essential "gatekeepers" that gather information, allowing us (historically) to find food, avoid danger, learn, reproduce, and effectively interact with our environment. 

In the past, when one or more of our senses was deficient in some respect, our ancestors applied, at first their ingenuity, and later their science, to augment the deficient sense to improve performance.

Losing one sense can cause the brain to rewire itself, reallocating resources to enhance remaining senses, particularly if the loss occurs early in life or if the individual trains to use other senses more intensely, e.g., blind individuals often having a keener sense of hearing or smell. 

 

Sight

Over 8 million Americans experience some form of vision impairment or loss, with around 1 million being completely blind.  Vision loss can result from common age-related conditions like cataracts, clouding of the eye's lens that causes blurry or foggy vision - the leading cause of blindness worldwide; macular degeneration that destroys sharp, central vision by damaging the center of the retina; glaucoma, a group of diseases that damage the optic nerve, often due to high pressure inside the eye; and diabetic retinopathy, complication of diabetes where high blood sugar damages blood vessels in the retina.  Vision impairment can also be caused by refractive errors, Including nearsightedness, farsightedness, astigmatism, and presbyopia (decline in focus ability); plus, sudden medical emergencies.

The history of vision improvement spans from ancient magnifying aids, to eyeglasses, to contact lenses, to surgical options.

In the 11^th-13^th centuries in Europe, monks used "reading stones,” segments of glass or quartz spheres placed directly on top of text to magnify the letters.

The first eyeglasses appeared in Italy around 1285, simple convex lenses (for farsightedness) set into frames of bone, wood, or leather that clamped onto the nose, helping medieval monks and scholars read.  Concave lenses were developed in the early 1400s to correct nearsightedness, making objects appear smaller but clearer.  Frames evolved from simple nose-pinchers to incorporating arms (temples) that rested over the ears, resembling modern designs by the 16^th century.  In 1784, Benjamin Franklin invented bifocals by combining distance and reading lenses in one frame.  Cylindrical lenses for astigmatism were developed in the 1820s.  Polarized sunglasses were introduced in 1936 to reduce glare.  Lightweight and durable plastic lenses emerged in the 1980s, replacing heavier glass.  Eyeglasses transformed from mere medical devices into fashion accessories, with modern advancements including progressive lenses, coatings, and advanced materials. 

The earliest pictorial evidence for the use of eyeglasses is Tommaso da Modena‘s 1352 portrait of Cardinal Hugh de Provence reading in a scriptorium.

Diagnosis of vision problems progressed also.  The ophthalmoscope invented in 1851 allowed doctors to see inside the eye to identify vision issues.  Snellen charts (see figure below), invented in 1862, standardized visual acuity measurement. The establishment of the National Eye Institute (1968) spurred research, leading to breakthroughs and expanding the scope of optometric practice.

The Snellen chart standardized visual acuity measurement.

The first large/stiff contact lenses were fitted in 1888, but it wasn’t until much later that plastic contact lenses (1938) and silicone hydrogel lenses (2002) made contacts more comfortable.

In the late 20^th century, vision correction surgeries like LASIK allowed reshaping of the cornea to fix nearsightedness, farsightedness, and astigmatism, while Refractive Lens Exchange surgery allowed replacement of the eye's natural lens for significant vision changes.  Cataract surgery replaced cloudy eye lenses and often resulted in sight improvement.  These revolutionary procedures offered a surgical alternative to glasses and contacts, allowing for permanent vision correction.

The future of vision correction involves personalized laser surgeries enhanced by artificial intelligence for precision, smart contact lenses monitoring health (glucose, pressure), novel implantable lenses, and gene therapies to correct genetic mutations causing sight issues, alongside emerging technology like robotic surgery.

Also under development is a retinal prosthesis, a "bionic eye" that restores some vision to people with severe blindness by bypassing damaged photoreceptors using a camera, processor, and an implanted electrode array that stimulates the retina with electrical pulses, allowing users to perceive light and shapes.

The goal is safer, faster, more customized, and even permanent vision solutions. 

Hearing

Over 50 million Americans experience some degree of hearing loss, affecting about 1 in 7 people, with rates increasing significantly with age.  Hearing loss is primarily caused by aging, exposure to loud noises, infections, earwax blockage, injury, or genetic factors. 

The history of hearing improvement began with ear trumpets, then evolved to bone conduction devices, bulky electronic hearing aids, miniaturization and digital processing, Bluetooth connectivity, and medical breakthroughs like cochlear implants for severe hearing loss.

Starting in the 17^th century, conical, passive devices (ear trumpets) made from animal horns or metal were the primary hearing aids, collecting and funneling sound waves to the eardrum.  Collapsible trumpets (late 1600s) and headband-attached versions (1800s) made them more portable and discreet. 

The first hearing aids were ear trumpets, funneling sound waves to the eardrum.

By the late 1800s, The first commercial bone conduction devices emerged, using teeth or the mastoid bone to transmit sound, helping the deaf hear music and speech. 

In the late 19^th century, the invention of the telephone and carbon transmitters paved the way for the first electric (though bulky) hearing aids, which could transmit and amplify sound as an electrical signal.  By the 1920s, vacuum tubes were used to provide significant sound amplification.  In the 1940s-1950s, transistors replaced vacuum tubes, making hearing aids smaller and lighter - pocket-sized.  In the mid 20^thcentury, in-the-ear and behind-the-ear hearing aids were developed. 

The world’s first commercial vacuum-tube hearing aid with a single earphone on a headband - large, fragile, and not easily transported.

The beginning of the digital age (1980s-1990s), with microprocessors, enabled digital hearing aids, allowing better sound quality, noise reduction, and programmability tailored to a user's specific hearing loss.

In the 2000s, miniaturization led to receiver-in-ear canal hearing aids, Bluetooth connectivity for streaming, and artificial-intelligence (AI)-powered features to analyze environments in real-time, suppress background noise, focus on speech, and even offer language translation. 

In the late 20^th century, surgically implanted electronic devices (Cochlear implants) emerged to provide a sense of sound to people with severe to profound hearing loss by bypassing damaged parts of the ear and directly stimulating the auditory nerve, allowing the brain to interpret these electrical signals as sound, with benefits including improved speech understanding and music appreciation.

The future of hearing aids includes smarter; smaller devices using AI for personalized sound; seamless Bluetooth connectivity for direct streaming from TVs, smartphones, and smart home systems; and incorporation of biometric sensors to track heart rate, physical activity, sleep, and stress - becoming comprehensive wellness trackers.

In essence, hearing aids are evolving into powerful personal devices that improve hearing, monitor health, and connect us to the digital world, moving beyond the traditional role as simple hearing amplifiers. 

Finally, research is advancing toward cell therapy treatments that could potentially reverse deafness, not just manage hearing loss.

 

Smell and Taste

Approximately 20% of American adults (about 1 in 5) are affected by some form of smell or taste disorder.  Loss of taste and smell is commonly caused by viral infections (like colds, flu, COVID-19), nasal/sinus issues (polyps, sinusitis, allergies), head injury, aging, certain medications, smoking, and dry mouth, but can also signal neurological conditions, tumors, or chemical exposure, often due to inflammation blocking scent signals or damaging nerve pathways.

Smell and taste are deeply linked, with smell providing most of what we perceive as "flavor" (the complex experience of food) while taste detects basic sensations (sweet, sour, salty, bitter, umami) on the tongue, but odor molecules traveling from the mouth to the nose during chewing create the rich, nuanced experience of food, which is why food seems bland with a stuffy nose. 

Our tongue's taste buds pick up basic tastes from chemicals dissolved in saliva.  As we chew, volatile aroma compounds from food travel up the back of our throat to receptors in our nasal cavity.  Our brain merges these basic tastes with the complex smells from our nose, creating the perception of flavor. 

What we call taste is mostly flavor, a combination of smell, taste, texture, and temperature.  When our nose is blocked, we lose most of this olfactory input, and food becomes bland, highlighting that smell contributes roughly 80% to flavor perception.  Smell also strongly connects to memory and emotion, influencing food enjoyment and decisions. 

Smell. Ancient civilizations viewed smell as a gateway to physical and spiritual health, and employed intensive therapies to clear nasal "blockages."   In c. 3000 BC, in ancient India, medical oils were administered through the nasal passage to treat loss of sensation. Other therapies included herbal smoking and forced vomiting to purge excess phlegm believed to hinder smell.  In c. 200 BC, traditional Chinese Medicine (TCM) used acupuncture and heat therapy at specific points on the face for nasal/sinus relief and opening the face/mind.  TCM practitioners also used nasal irrigation and "stuffing" herbs into the nostrils to clear obstructions.

In the 2^nd century BC, Greek physician Claudius Galen linked the five senses to the brain and treatments to improve smell focused on balancing basic body substances (humors) through diet and purging to ensure the "vital spirit" could reach the brain. 

As modern anatomy emerged, in the 1890s-1990s, the focus on smell moved toward understanding and eventually replicating the olfactory system.  In 1954, microelectrodes were measure aromas, followed in 1982 by the first "intelligent" artificial nose using a sensor array to identify up to 20 distinct odorants.  In 1991 American neuroscientists Linda Buck and Richard Axel identified the olfactory receptor gene family, which provided the roadmap for modern smell restorative research. 

American neuroscientists Linda Buck and Richard Axel received the Noble prize for their work on smell research.

 

The 21^st century introduced methods to physically retrain or regrow the olfactory system.  Retraining involves sniffing at least four distinct scents - typically rose, lemon, clove, and eucalyptus - twice daily for 15-30 seconds each.  Studies show this can significantly improve the sense of smell over 3-14 months.  In 2012, scientists restored the sense of smell in mice using gene therapy to regrow smell-detecting nasal hairs.  In 2019, researchers successfully used intranasal stem cell droplets to replace damaged neurons in mice, restoring their ability to detect unpleasant odors.

Today, improving a problematic sense of smell involves a combination of established therapeutic practices, emerging medical treatments, and innovative "smell-aid" technologies.  For smell loss caused by inflammation or nasal polyps, oral or topical steroids remain a primary treatment.  Active vitamin D delivered via nasal spray may effectively treat inflammation-related smell loss where oral supplements failed.  Omega-3 supplements can be effective in supporting olfactory recovery. 

Prototype devices now exist that use an "electronic nose" (e-nose) to capture odors and translate them into electrical pulses.  These pulses are delivered to the wearer’s nose, allowing the brain to "feel" and eventually identify different scents through touch-like sensations.  Recent 2025 studies have successfully used non-invasive radiofrequency stimulation to target olfactory nerves in the brain, improving scent detection for over a week after a single treatment. 

Research into olfactory implants and gene therapy is underway to help those with smell loss, with potential for future bionic noses.

Taste.  The history of trying to restore/improve the human sense of taste parallels that of smell through the 1900s - because of the close link between smell and taste.

From the 1900s-1990s, researchers focused on identifying the biological limits of taste and the genetic differences between individuals.  In 1908, Japanese chemist Kikunae Ikeda identified glutamate as the source of the fifth taste, "umami," and later developed Monosodium Glutamate as the first mass-produced flavor enhancer.  In 1991, American psychologist and pioneering taste and smell researcher, Linda Bartoshuk, identified "supertasters," individuals with a higher density of taste buds, sparking research into how to modulate flavor for those with lower sensitivities. 

American psychologist and pioneering taste and smell researcher, Linda Bartoshuk.

Since 2000, taste improvement technology has focused on "digital seasoning" and biological regeneration of taste receptors.

In 2014, Maine researcher, Nimesha Ranasinghe, developed an interactive, electronically enhanced set of eating utensils using light and electrical pulses to digitally simulate sour, salty, and bitter sensations.  In 2024-2025, there was commercial release of devices that use weak electrical currents to enhance the perceived saltiness of food, allowing people on low-sodium diets to "taste" salt without consuming it. In 2025, researchers at Ohio State University developed a wearable oral device that uses gel-filled chambers and tiny pumps to deliver flavor profiles directly to the tongue, intended for use in Virtual Reality or for patients with taste disorders.

Active clinical trials in late 2025 explored using human taste bud-derived stem cells to regrow damaged taste receptors in patients who lost their sense of taste due to chemotherapy or neurological conditions.  Today, AI-Powered specialized devices mimic human neural pathways to help patients with neurological damage "feel" tastes again by converting chemical data into electrical signals that the brain can process. 

Practical taste improvement steps we can take today include mindful eating (chewing slowly, mentally connect aromas to tastes, serve hot and cold foods together or try different textures and colors, and keeping a taste journal to identify and recall specific flavors and smells), boosting flavors with herbs/spices, improving oral hygiene, reducing processed foods, quitting smoking, and exploring new foods, all while paying attention to smell, as it heavily influences flavor.  If problems persist, consult a doctor to rule out underlying issues like infections. 

The future of taste improvement centers on enhancing flavor perception through neuro-technological devices, AI-driven nutritional design, and pharmacological interventions, aiming to heighten sensory experiences and aid medical diagnostics.  Key developments include electric taste stimulation, personalized nutrition, and enhanced culinary experiences. 

 

Touch

While specific, comprehensive data on "touch disorders" is limited, surveys indicate 38% of older adults have reported a fair sense of touch, and 32% report a poor sense of touch.  Loss of the sense of touch is primarily caused by peripheral nerve damage, spinal cord issues, or brain injuries that disrupt neural pathways.  Common causes include diabetes-related neuropathy, physical trauma (crushing, cutting, or burning nerves), infections, stroke, or compression, such as carpal tunnel syndrome.  Frostbite, chemical burns, or even migraines with aura can cause temporary or permanent loss of touch. 

 Historically, efforts to restore or increase the human sense of touch have progressed from philosophical theories and social practices to advanced neurological and technological interventions. 

In ancient Greece, in the 4^th century BC, Aristotle identified touch as one of the five primary senses, arguing it was the fundamental sense distinguishing animals from plants, and humans from other animals.  Shaking hands began in the 5^th century BC to signal peace and trust, using touch to confirm the absence of weapons.

In the 19^th century, anatomists used microscopes to identify touch neurons (sense receptors located throughout the body), and early sensory history noted people's desire to touch artifacts for learning.

In the early 20^th century, scientists began recording electrical impulses from single nerve fibers, cataloging responses to different stimuli (pressure, temperature) and revealing diverse touch receptors.

American psychologist Harry Harlow conducted a series of landmark experiments at the University of Wisconsin-Madison from the 1950s through the 1970s, using rhesus monkeys to challenge prevailing behaviorist theories which claimed infants only bonded with mothers because they provided food.  Harlow's monkey experiments that showed touch (comfort) was crucial for development, contrasting with earlier behaviorist ideas discouraging physical affection.

In the 1970s, researchers like American neuroscientist Paul Bach-y-Rita developed tactile substitution systems to help the blind "see" through tactile feedback, stimulating the skin (often on the back or tongue) to convey visual information to the brain.  His core philosophy was that "we see with the brain, not the eyes," suggesting that the brain can reorganize itself to process information from an alternative sensory source if the primary one is damaged. 

American neuroscientist Paul Bach-y-Rita developed tactile substitution systems to help the blind "see" through tactile feedback.

Since the 1990s. there has been an explosion in touch research, focusing on multisensory integration, haptics (simulating touch through vibrations, motions, or forces), and the brain's representation of touch. 

Molecular genetics enabled precise mapping of touch neurons.  It was discovered that brain stimulation electrodes can evoke touch sensations (tingling) in brain areas, even after loss.  Researchers have developed ways to create artificial touch, giving prosthetic users sensations of pressure and texture through nerve connections.  Wearable devices now simulate the "feel" of virtual objects, allowing users to experience resistance, temperature, and texture.  Current research focuses on engineering tactile sensors for prostheses and surgical robots to give them human-level competence in physical exploration.

The future of restoring and increasing the sense of touch is rapidly advancing through Brain-Computer Interfaces (BCIs), nerve sensors implanted in the body, and artificial skin that can incorporate sensors - enabling neurological impaired and paralyzed individuals and amputees to feel sensations like pressure, texture, and temperature.   BCIs are systems that establish a direct communication pathway between brain electrical activity and external devices, allowing users to control computers or robotic limbs with their thoughts.  The process is to stimulate the brain's sensory cortex, and using self-powered sensors to convert touch into electrical signals, with goals to create intuitive, natural, and permanent sensory feedback. 

Future systems may use AI to compute the best stimulation patterns, adapting to the user's brain activity for more natural, nuanced, and realistic sensations.

 

Conclusions

Based on recent research and technological advancements, efforts to restore or improve the five senses (vision, hearing, smell, taste, touch) are transitioning from simple corrective aids to sophisticated, high-tech solutions aimed at regenerating sensory function.  Vision advancements include retinal implants and AI-powered glasses that can read text or identify faces for the blind. Hearing devices are becoming "intelligent" systems, with cochlear implants allowing the deaf to hear by bypassing damaged ears. Efforts to restore or improve the senses of smell and taste have reached a significant inflection point, transitioning from basic rehabilitation to high-tech regenerative and electronic interventions.  Emerging neuro-prosthetics (like "electronic skin") and wearable sensors are successfully simulating the sense of touch by translating pressure into nerve signals.

While millions still suffer from sensory impairment, advancements in gene therapy and regenerative medicine are beginning to offer hope for repairing sensory cell loss, rather than just masking the symptoms.

 

 

When all is said and done, we exist only in relation to the world, and our senses evolved as scouts who bridge that divide and provide volumes of information, warnings, and rewards. - Diane Ackerman

 

 

 

Sources

My principal sources include: ”From Reading Stones to Smart Lenses: The Journey of Vision Correction,” uoosd.com; “A brief history of hearing aids,” fallsofsound.com; “VSP Vision Explores the Future of Senses in New Report Spotlighting the Innovations Redefining How We See, Hear, Smell Taste, and Touch,” vspvision.com; “The Future of Making Sense of the World,” medicalfuturist.com; plus, numerous other online sources, including answers to many queries using Google in AI-Mode.