"Scientists have theorized that we used nonverbal communication, including touch, long before we used language. We begin progressing from nonverbal to verbal communication as soon as we are born. Through the touch of their parents and caregivers — hugs and kisses, nursing and holding — infants learn about the world around them. Psychologists have demonstrated the importance of touch in child development. Touch enhances feelings of security in children and improves their social skills. In famous, tragic cases of children who grew up in orphanages in Romania with hardly any human contact, the lack of touch stunted their emotional, social, and cognitive development.

"Touch also influences adults' behavior, such as compliance, altruism, and risk taking. In one study salespeople in a supermarket approached shoppers and asked them to taste a new snack. While making the request they touched some of the shoppers lightly on the upper arm. That touch increased shoppers' willingness to try a sample and even to buy the snack. A recent study found that a light tap on the shoulder increased financial risk taking in people, probably due to a resulting sense of enhanced security. Another study found that waitresses who touched customers on the hand or on the shoulder for about a second received greater tips. Yet the same brief touch did not influence customers' ratings of the waitresses or their ratings of the atmosphere of the restaurant; this suggests that the customers were not aware of the effect of the touch on their behavior.

"Touching another human being increases trust and cooperation. It reduces our perception of threat, increases our sense of security, and relaxes us. Anxious people benefit from touching someone or holding hands. When people go to the doctor to have a potentially painful procedure, a light touch on the head or shoulders by a health-care provider can reduce their anxiety. A massage after a hard day at work helps me relax, even if my muscles are not particularly tense and I am not especially anxious.

"The need to be touched has led scientists to try to design and create products that mimic the feeling of human touch. The 'hug shirt,' for instance, communicates the sensation of touch for people who are physically separated: it is made of soft, pleasant-feeling materials and has sophisticated pressure sensors that are activated by various technologies such as mobile phone applications. It even stimulates the emotional reactions that follow a hug, such as a decreased heart rate. Another invention uses a doll that transmits a hugging sensation to a child wearing a special 'cyberpajama.' People are willing to spend time and money to 'stay in touch' with technological innovations as well as with the old-fashioned long embrace after being apart."