How Touch Informs Vision and Hearing


Research to Practice • Practice to Research

How Touch Informs Vision and Hearing

Posted on January 11, 2016

1 comments 1480 Views

By Lyn Ayer

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


Tiny baby hand holding a mother's thumb

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.


Kangaroo Care


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


a child's hand and an adult's hand doing fingerpainting

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





Try this


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 a continuum


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:

  • degree
  • 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: 

http://pediatricot.blogspot.com/2011/04/treating-tactile-defensiveness.html


At the end of her blog, this OT suggests reading the book, “Too Loud, Too Bright, Too Fast, Too Tight” by Sharon Heller:

http://www.amazon.com/Loud-Bright-Fast-Tight-Overstimulating/dp/0060932929



Touch Perception


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.):

http://www.nursingtimes.net/clinical-subjects/dermatology/sense-of-touch-the-perception-of-touch/736367.fullarticle


Want to test your sense of touch?  Here are a couple of ways to do this.  Many of you may recognize these:

http://www.hometrainingtools.com/a/sense-touch-perception-experiment


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


A cortical homunculus drawing – will show the  extent to which touch is represented in the brain.

You can look it up on Wikipedia or a textbook:

https://en.wikipedia.org/wiki/Cortical_homunculus

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: 

http://faculty.washington.edu/chudler/flash/hom.html

illustration of the brain

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. 



Related topics:

Embodied cognition:

https://www.psychologytoday.com/blog/beyond-words/201202/embodied-cognition-what-it-is-why-its-important

http://www.scientificamerican.com/article/embodied-cognition-our-inner-imaginings/


Touch-emotion synesthesia:

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.


1 Comments

This is an excellent resource! I plan to share with my students in a course on Movement and Learning.
Thank you,

Patti Blasco

Patricia  Blasco

Posted Feb 4, 2016 by Patricia Blasco

We value your comments

Let us know that you are a human.
What does the 'R' stand for in TRI?

The Research Institute : Western Oregon University : 345 N. Monmouth Ave. : Monmouth, OR 97361
Contact Us: 800-438-9376 | info@triwou.org