More than a feeling

One of the most amazing things about modern technology is how it can connect us in ways that would have seemed almost incomprehensible a few decades ago. We can keep in almost constant audiovisual contact with distant family and friends; conduct complex business in global markets; and even play elaborate, interactive video games with hundreds of others.

During the COVID-19 pandemic, these technologies came into their own and enabled our work and social lives to continue, in a fashion. While some people welcomed the space, many of us began to miss actual, physical closeness with others and specifically a shared sense of touch – be it a simple greeting hug or a comforting stroke on the arm when upset. Others, meanwhile, missed the affirming handshake to seal a business deal or even the celebratory high five with teammates at a sports game. Many of these moments from our shared experience of touch became contentious, at times even forbidden.

But what exactly is unique about touch and how is our understanding of it evolving? University of Bristol researchers are exploring how touch has shaped the human experience, from Medieval times to the present day, and how it is developing in concert with technology.

Touch in the spiritual and devotional

The senses have been of interest to thinkers and philosophers for centuries, not least because they connect our inner self to the external world. Aristotle believed that true knowledge came from the senses and proposed a hierarchy, with sight being the ‘noblest’ of them, followed by hearing, smell, taste and then touch.

Interestingly, senses in the Middle Ages were understood as being more closely related than they are now, as Beth Williamson, Professor of Medieval Culture in the Department of History of Art, explains.

‘One of the ways in which sight was conceptualised at the time involved rays going from your eyes towards the object and the object itself emitting rays, with a touching of those rays in between. So, sight could very much be seen as a species of touch.’

 Professor Williamson’s research explores how devotion is understood through different sensory modalities. The touching of relics, including body parts of deceased saints or objects they used, played an important role in this period.

 ‘You would get a sort of spiritual power from it,’ Professor Williamson says. ‘People also took vows and oaths by touching relics, making that contact with holiness. You see that on the Bayeux Tapestry depicting the Norman Conquest of 1066. Harold, Earl of Wessex, touches a relic to say that he’s going to be loyal to William of Normandy, who saw himself as the rightful heir to the throne of England.’ In the Middle Ages, when an individual became the servant or vassal of a lord, they would take part in a ceremony where they would place their hands between the hands of their master, which is where the Christian prayer gesture originates from – your hands between the heavenly Lord’s.

 Of course, touch through the Medieval period was not always sacred. Though a complete understanding of germ theory was centuries away, the bubonic plague pandemic of the late Middle Ages generated ‘contactless’ innovations reminiscent of our early efforts to contain the COVID-19 pandemic. Plague stones would be positioned on the outskirts of villages, with money steeped in vinegar to facilitate trade and avoid infection. Pitch and Pay Lane, close to the Clifton Downs, gets its name from that period, as the point where Westbury villagers would pitch their goods to inhabitants of plague-ridden Bristol.

Touch and the human condition

Decades of research and experimentation have helped to reveal the great complexity of touch and its relationship with the other senses. It is now believed that touch is the first sense to develop in the growing foetus in the mother’s womb, at around eight weeks gestation.

We also know that touch, or more accurately tactile perception, consists of several distinct sensations, including pressure, temperature, vibration and pain. These sensations are transmitted to the brain via specialised receptors in the skin, including thermoreceptors, mechanoreceptors and nociceptors.

Clearly, as a survival mechanism, touch helps keep us out of harm’s way by avoiding anything that causes initial pain. But it’s also a key part of what makes us human, as Nathan Lepora, Professor of Robotics and AI, reflects:

‘While vision gives you geometrical feedback of where things are in space, touch gives you feedback about forces, contacts and interactions, and the control of those forces is essential when manipulating objects. Although we’ve seen sophisticated tool use in chimps and even crows, it’s nothing like the level of dexterity in humans. ‘Technology is basically tool use. It all stems from making things with our hands. I would argue that touch was critical in the development of human intelligence.’

Professor Lepora also notes the importance of tactile perception in the feet and legs, which detect and control slippage and grip, thus enabling us to walk upright (it’s basically impossible to walk with an anaesthetised leg).

Another key aspect of what makes us human is our ability to form bonds with other people across large groups – and touch plays a critical role here as well.

Experiments have shown that through touch alone we can communicate and discriminate between emotions including gratitude, anger, love and fear with a greater degree of accuracy than facial and vocal communication. A raft of studies in recent decades has also demonstrated that human touch is associated with clear physical and health benefits.

Professor Michael Banissy recently moved to Bristol to head up the School of Psychological Science and has a keen interest in touch. ‘For me personally, touch is one of my favourite senses and like many people I really missed that during lockdown, when it was taken away. It’s fundamentally important and connects us to each other and to the world around us. From infancy, we’re using touch to learn about our world and explore.’

In January 2019 Professor Banissy led an ambitious study called The Touch Test. Thought to be one of the world’s largest studies of touch, it gathered responses from almost 40,000 people in 112 countries. Among its key findings were that 72% of people viewed interpersonal touch positively and 43% of typical adults felt that society does not enable us to touch enough.

There are of course caveats here. Unsolicited and unwelcome touch elicits a vastly different response to a mutually shared experience. There is also a whole community of neurodivergent people, including those on the autistic spectrum, for whom touch can be completely overwhelming and even distressing.

Professor Banissy comments: ‘Touch is incredibly nuanced and varies from person to person and from situation to situation, even within the same person. One day you might absolutely love your partner, say, stroking your arm, but if you’ve had a hectic day, you might just want space.’

The findings of The Touch Test were in a way bittersweet, as they showed the importance of touch just before we entered lockdown in March 2020 and were soon to be denied it. Even before the pandemic, the ‘epidemic of loneliness’ seen in many modern societies, and the associated lack of physical contact, was something researchers were trying to address.

A therapeutic robot seal called Paro made headlines a few years ago when it was deployed in care homes throughout Japan. With tactile sensors covering its fur and touch-sensitive whiskers it responded to stroking and purportedly reduced stress in residents.

More recently, a group of researchers from Bristol led by Dr Chris Kent, Associate Professor in Cognitive Psychology, developed a huggable, cushion-like device that mechanically simulates breathing, and has been shown to help alleviate anxiety in students prior to a maths test. Indeed, the breathing cushion was found to be just as effective at easing anxiety as guided meditation.

Talking about the development of the cushion, Dr Kent comments: ‘My initial interest was around new university students moving away from home and how they might miss those close relationships with parents. After becoming a father myself, I realised the importance of the tactile modality in connection with children. With very young children you can solve most of life’s problems with a cuddle! Then the pandemic really brought into focus that need for a connection.’

Shaping the future of touch

Some researchers are looking even further into the future of touch – how we might make best use of our own tactile abilities and even imbue robots with a sense of touch.

One such academic is Dr Anne Roudaut, Associate Professor in Human–Computer Interaction in the Department of Computer Science. ‘I’m interested in understanding how humans interact with and manipulate tangible technologies, and particularly how we use the formidable attributes we have, our hands, and how we can develop digital tools that are better adapted to us,’ she says. ‘Humans have evolved in an extraordinary manner, spanning millions of years. But in terms of using digital tools, we are only 40 years in really.’ She notes that most consumer devices are developed through a ‘technology-driven approach’ based largely on rectangular and flat screens that are easy to manufacture, but not necessarily adapted to human hands and touch. ‘I think there is a real opportunity to rethink the way we build interactive technology, and to start from scratch, working with material scientists, physicians, computer scientists, psychologists and others, towards devices that truly unleash users’ interactive potential.’

Dr Roudaut and a growing community of researchers are in the early stages of developing devices that change their shape depending on the task required and could even be optimised and personalised to the sensory needs of each individual. Such shape-shifting devices could also be used in education and allow children with different sensory faculties to be taught together, inclusively.

‘For example, when teaching about the formation of continents, children would physically interact with, and mould, actuated interactive maps in order to experience the impact of geological forces,’ Dr Roudaut says.

As well as bringing augmented tactile experiences to a diverse spectrum of humans, researchers are also seeking to bring touch to burgeoning robotic life.

Professor Lepora and his team have developed a core technology called the Tactile Fingertip (TacTip). Inspired by the structure of the human glabrous (hairless) skin found on our hands, the TacTip has an array of internal pins which deform when in contact with an object. This produces artificial nerve signals that mimic those of humans. The group has fitted the TacTip to several different robotic hands. Watching videos of these hands, which have near-human levels of dexterity, is quite mesmerising – they can gently pick up a delicate piece of origami sculpture, clearly feeling as the paper yields here and there. When gripping a ball they can also detect and correct for a slip and react quickly to re-grasp.

The TacTip technology should enable research groups around the world to develop robots and autonomous machines with a sense of touch and human-like dexterity, which could pave the way for applications such as the handling or sorting of goods or even nursing and caring.

Having established that touch is a key part of what makes us human, this gives us some serious philosophical and even ethical points for debate. Our society is growing accustomed to artificially intelligent machines that have amazing abilities in logic, reasoning and language. Somehow a sense of touch, which is so special and personal to us, takes it to a different level entirely. Will we accept the touch of robotic life, and embrace it as equal to our own, forming group bonds with our machine brethren? Only time will tell.