Individuals tend to have definite preferences when it comes to the sensations fabrics on their bodies: flannel or silk pajamas? Exercising in tightly-fitting stretch fabric or in loosely-fitting oversized cotton training gear? The difference between deep and light touch is one of the central parameters that define the role of tactile input in various experiences.
An overly strong squeeze, or a heavy book landing on your foot is painful. But most of the time, the sensation of deep pressure on the skin is processed in our brains as pleasant and calming. Deep tactile input can improve experience in a variety of daily situations.
Consider the case of the winter comforter. A light fluffy down-filled comforter can feel wonderfully warm on a winter night. But for some users, its light weight may not feel cozy enough. Many people need a weightier sensation to anchor their body, which helps them relax into sleep. Feeling good under the blanket, it turns out, is not only a question of temperature. Often, the perceived sensation of comfort comes from a combination of warmth and deeper tactile input, which sends information to the brain letting you know: "I'm warm and cozy."
Light touch results in a very different sensation on the skin. A mosquito softly landing on your arm produces a barely detectable tactile stimulus, and yet the swat in response is swift. How about that strand of hair repeatedly falling on your forehead?--it is driving you crazy! Light touch is alerting and sometimes irritating, yet it can also be a pleasant, even pleasurable experience. Just think of the sensual touch of silk or the pleasant sensation of bubbles lightly touching your skin in the bathtub.
Although individual differences in sensitivity to deep versus light touch can be significant, each person usually has a wide sensory spectrum that ranges from "feels wonderful" to an absolute "Aghh!!!". Moreover, in many cases it is not even necessary to be in actual physical contact with an object or a surface, to categorize sensation they produce on the skin.
The processing of tactile input has a long memory-as evidenced by the incredibly strong attachments people have to specific fabrics, upholsteries, or the food textures. In the design of objects, it may be impossible to please everyone's tactile preferences, but it is plausible to highlight tactile properties in a manner that emphasizes potentially positive tactile associations.
The chairs in the image above are made of materials with vastly different tactile properties: Leather, wood, mesh, metal, plastic and upholstery. Responses to these chairs are influenced by an individual's tactile memories of each texture. For some, a leather chair suggests a pleasant and smooth sensation that is associated with comfort. For others, leather evokes a tight, sweaty, and sticky sensation, and a desire to stay away. Some people may feel neutral when it comes to leather surfaces, but most are likely to experience the "oh yes!" and "no!" responses when exposed physically or imaginatively to various textures touching their skin. These knee-jerk responses permeate our interactions with the objects of daily life, often underlying our material habits and consumer choices.
Think of a wooden dining table versus one made of steel and glass. Various characteristics of the table would influence potential consumers looking to update their dining room. Shape, size, color schemes, and price--all play an important role, and may be subject to negotiation among the purchasing decision makers. However, people are unlikely to buy a table that has a surface they do not enjoy looking at, or touching.
The dense fibers and natural colors of a wooden table bring to mind a homely feeling, while the smooth, cool, and shiny appearance of glass and steel are evocative of modernity and cleanliness.
Whatever we do, wherever we are, we are always experiencing touch. For the most part, our tactile sensation goes unnoticed-as it should. Who wants to expend precious neurological energy on constantly feeling the shirt on their back or the pen in their hand? However, if we approach the end range of our tactile comfort zone, either the pleasant or the agitating sensation of it, touch springs into our awareness with immediacy and force. Our response to pleasant or repulsive touch dims other sensory information, especially when we touch something hot, sharp or slimy.
Discrimination of hot/cold and sharp/dull as well as the sensation of pain, are part of a defense mechanism built into the tactile sense. These sensations are as ubiquitous in our daily lives as deep and light touch. Anyone who ever picked up a hot pot from the stove thinking that the handle does not conduct heat, remembers the pain and what they thought about the design of that pot. We need the objects in our lives to be safe and we need clear indication of danger where it exists.
To alert the user to the potential danger of touching certain objects under certain conditions, experience designers resort to communication via the other senses, by providing audible or visual alerts such as those represented in the image below.
We touch the world and the world touches us. Every object or environment, physical or virtual, has a tactile aspect, which sometimes draws or repels us. The sensations sent from tactile receptors in our skin to the brain can easily overtake other messages when danger is involved, but in many cases, the magnitude and character of these sensations can be manipulated in the design of experiences.
Visual, auditory, and tactile senses that influence and shape experience are joined by smell, taste, a sense of our body in space (proprioceptive sense) and a sense of our body versus gravity (vestibular sense) -- all play an important role in how we respond to objects and environments.
Furthermore, many objects, and certainly--most experiences, engage multiple senses and require an integrated processing of sensory data. Watching a movie, buying new shoes, pushing a child on a swing-we are constantly process inputs from numerous sources through our sensory system, interpret the data, and respond in thought, feeling, and action.
These are the raw materials experience design is made of, and designers have been thinking and shaping them throughout the history of civilization. Next, an exploration of mental processes, such as time perception, planning, and changes in effect.