How Touch Informs Vision and Hearing
Posted on January 11, 20161 comments 2840 Views
By Lyn Ayer
Lyn Ayer is the Director of the Oregon Deafblind Project. Lyn has been in Special Education for 41 years. Her jobs have been varied -- as teacher of the visually impaired/Orientation & Mobility instructor, principal of a school for the blind, rehabilitation specialist on a mobile team attached to an eye hospital, director of community programs in a rural area in India, director of a licensure program for training teachers of the visually impaired, and director of a state's deafblind project (12 years in Wisconsin, 8 years in Oregon).
The importance of developing the sense of touch
Before you start reading this article, consider these questions:
- In your view, what are the similarities or differences between touch and vision?
- How are touch and cognitive/intellectual functions connected?
Hint: Think of how each of us uses touch on a daily (functional) basis.
Touch is the first sense to develop
According to some researchers, touch is the sense that “educates” vision and hearing. It is how we associate tangible ideas with the distance senses of vision and hearing. We could be looking at something that we know is “soft,” but the only reason we really KNOW this, is because we have touched it or something like it, and thus learned the concept of “soft.” Vision didn’t teach us this.
Touch is extremely important in early bonding
I remember having a mother call me to take a
look at her newly-adopted toddler.
She thought her child could not see—because of how she behaved. She also said her toddler would not hug
her back and really was like a floppy doll when her Mom hugged her. It turned out that the child had normal
vision and sensory input, but had been in a facility where she just lay in a
crib and no one touched her — not even when she was being fed.
I left the Mom with one main idea —
“Love your child — and keep on loving her”; that, and advice to learn infant
massage. Two years later I saw
them at the grocery story and did not even recognize the child sitting in the
cart, joyful, animated and chatty.
The whole science of what has come to be known
as Kangaroo Care is based on the value of skin-to-skin touch between babies and
parents. Briefly, doctors dealing
with premature and critically ill infants who did not have access to adequate
incubator units had mothers hug their babies closely, skin-to-skin. They found, to their surprise, that
babies they had expected to die would not just survive, but thrive.
The skin-to-skin action created a “sharing” between mother and infant which normalized breathing, blood flow and much more. It was like an expanded “osmosis” experience between them. To look at all the “benefits” and see where the term "Kangaroo Care" comes from, check out the Cleveland Clinic site: http://my.clevelandclinic.org/childrens-hospital/health-info/ages-stages/baby/hic-Kangaroo-Care
Touch is not inferior to vision and hearing
Touch should NOT be considered “more primitive” or inferior to vision and hearing. In fact, it is the one sense that can help us survive if all other senses do not perform. Vision may “fail” us in some instances. For example – when we have a tiny splinter that can only be seen through magnification; or in detecting very fine surface variations; or in detecting grit in food.
The feedback from skin to brain is continuous – even in sleep
This continuous feedback is why we may go to sleep in one position and wake up in another (a good reason to remember to reposition a child whose body cannot change position even when the child’s brain says it needs to change.) It is also why we feel a stone that suddenly gets into a shoe while we are walking along even though we were no longer aware of our shoes or our feet, but were just moving along!
A mirror of our passions and emotions
It is the most social sense, a mirror of our passions and emotions. Unlike with vision, we can “feel” that something is hot or cold, soft or hard, rough or smooth – in addition to the spatial attributes and how something looks. A splinter will prompt an intense emotional reaction %^$#@!, as does putting fingers/hands into something that is sticky or gooey—YUK! Sound familiar? Know a child who doesn’t like goo?
Emotions are a powerful motivator for tactile learning, and a good reason for us to appeal to a child’s sense of touch in the process of teaching him/her something. If a child is “tactile sensitive” (as we still call that reaction of taking the hands out of play), he/she will not really learn by watching or listening.
Take some simple examples that could just be visual or auditory images, but mean nothing to a child in functional terms — stirring pudding mix, pouring juice from a jug to a cup or glass, kneading dough, falling down and scuffing a knee, Mom kissing Dad, jumping into a puddle of water or a pile of fall leaves, a puppy pulling at a leash, a cat purring, going up and down on a teeter-totter or on a swing. None of these would have as much meaning without the sense of touch.
Touch lasts beyond our ability to see and hear
Touch functions even after seeing and hearing start to fade. This is why even with a person who cannot respond or is in a coma, visitors are encouraged to hold their hand(s) and perhaps stroke the hand, even if not talking.
One researcher calls the skin (which houses the “tools” of touch), a two-sided mirror with triple functions. It has:
- the outer
surface which informs us about the outside world,
- as well as the living world within the body,
- and the inner surface which communicates with the body’s inner cells and organs.
What is HAPTIC?
When you see the word “HAPTIC” – it is related to ACTIVE touch. In passive touch – the person does not move, and information is imposed on the skin by an outside source. In ACTIVE touch, the person is allowed to get objective information, make intentional movements, and perhaps manipulate what is felt. Without movement, you cannot discover details about an object such as shape and texture – or distances between objects
- Have you heard about “haptic technology”? You have probably experienced it. Learn more about it — and think about where this technology may be taking us! It is even being used by architects.
- Learn about “wearable technologies” related to haptics and how they make use of this:
- And watch this slideshare — to gain an even better understanding of how widely haptics is being used in our world:
Close your eyes. Have a friend touch various objects to your skin — without moving the objects on your skin or using too much pressure. You will not be able to tell the differences between them. Then, using the same objects, have your friend move the objects on your skin. You will get more information, but it will still not be a lot. Finally, ask them to place the objects in your hands so you can “explore” them. You will explore by MOVING your hands. It is possible that you can guess what the objects are — but this may be because you already have had experience with them and your brain remembers. Children who don’t have these concepts, need to explore to get them!
Touch is on
Touch is on a continuum: tactile sensation → tactile perception → tactile cognition. The continuum is bidirectional – bottom up, as well as top down (cognition to tactile sensation) when learned concepts influence what we feel. If either the bottom-up or top-down modes are interrupted by damage to the brain, this will result in clinical disorders.
Tactile defensiveness is one of these. This is hypersensitivity to touch due to a distortion in the central nervous system’s ability and capacity to process, regulate, and organize, in a graded manner, the:
- Intensity and/or
- nature of sensory input
Read this blog by a pediatric OT on this topic — and think of a child you know who has this issue:
At the end of her blog, this OT suggests reading the book, “Too Loud, Too Bright, Too Fast, Too Tight” by Sharon Heller:
Touch perception can be
- whole vs. part (e.g., what you might use in examining a toy)
- serial vs parallel (e.g. a fingertip for braille, or all fingers to move ahead and scan faster).
Below is an article on the perception of touch—from the Nursing Times (U.K.):
Want to test your sense of touch? Here are a couple of ways to do this. Many of you may recognize these:
Watch these two excellent videos on Haptic perception which explore how we examine objects through touch. These are Interviews with Dr. Roberta Klatzky, Carnegie Mellon University. Watch all the different ways in which someone explores objects, including raised line drawings:
More about the brain – and touch
You can look it up on Wikipedia or a textbook:
Notice the distribution of touch — and how much is concentrated in the hand and face alone. For fun, also take a look at this site for children — explaining the term homunculus:
The two hemispheres of the brain do different things within the area of touch, BUT laterality may be different for different individuals, and may change with intellectual experiences. Generally speaking:
- The left hemisphere is involved with WHAT is being touched – form recognition; and also fine details (e.g., subtle differences in roughness, smoothness, and softness).
- The right hemisphere indicates WHERE one is being touched – tactile localization; as well as holistic details (e.g., global features of an object, spatial layout, the length/shape/size of objects).
- When there is active touch (grasping the target) – there is also a HOW.
Interestingly, there are similar functions for vision – different areas of the brain dealing with WHAT one is seeing and WHERE it is.
Hand laterality seems to differ too and it worth exploring—but I will not do so in this article. Just to get your interest, it appears that the left hand is more sensitive to weight and thermal properties. Laterality is also said to be connected to directionality and the aptitude for this.
http://synesthesia-test.com/touch-emotions-synesthesia - emotions are demonstrated when touching different textures (e.g., denim, wax, sandpaper, silk).
Some resources for Research-based information in this article can be found in:
- From Active Touch to Tactile Communication – what’s cognition got to do with it? (Jude Nicholas)
- Touching: The human significance of the skin (Ashley Montagu)
- The Psychology of Touch (Eds. Morton A. Heller, William Schiff)
- Touch and Blindness: Psychology and Neuroscience (Eds. Morton A. Heller & Soledad Ballesteros)
This post originally published in the Oregon Deafblind Project Newsletter - December 2015. For more information about the Oregon Deafblind Project, go to oregondb.org.