Maria Konnikova, ‘The Power of Touch’, https://www.newyorker.com/science/maria-konnikova/power-touch, The New Yorker (March 4, 2015)
Touch is the first of the senses to develop in the human infant, and it remains perhaps the most emotionally central throughout our lives. While many researchers have appreciated its power, others have been more circumspect. (…) Like our other senses, touch comes in gradations. It is governed by an exquisite array of receptors that can distinguish minute variations in the external environment. Fast, slow, or in between? Hard, soft, or something else? Hot, cold, warm? Some receptors react only to caresses. Some send pain signals. Some tell us that we have an itch. Each type activates a different part of the brain, making us feel soothed or hurt, comfortable or distressed, angry or calm. (…) The electric touch of romantic love, the unsettling feeling of being watched, the relief of pain from mindful practice, or the essential touch that newborns need to thrive. (…) All of these diverse sensations (…) flow from the evolved nature of our skin, nerves, and brain. (…) If we often experience friendly or loving caresses, it’s safe to assume that we have a strong social network. (…) Emotions that are communicated by touch can go on to shape our behavior. (…) The more we learn about touch, the more we realize just how central it is in all aspects of our lives—cognitive, emotional, developmental, behavioral—from womb into old age. It’s no surprise that a single touch can affect us in multiple, powerful, ways.