A few thoughts on Skeffington’s circles that show how vision is sensoryMOTOR.
1.Where am I in space? – Anti-Gravity / Balance
General motor control (working against gravity) for locomotion, exploration, and organization of oneself within the environment – Learning how the body/limbs/extremities work. Need to have a solid understanding of our position in space and how our bodies work so we can direct finer muscles effectively (such as our eyes). Balance and posture in space provides a basic frame of reference for orientation and spatial localization.
Skeffington believed that the anti gravity subprocess is the foundation of the emergence of vision. The anti gravity sub-process is the total sensorimotor system that is used for spatial organization, exploration, and movement through an environment by an infant. It is formed in utero as sensory and motor neurons start to link – including the emergence and integration of primitive reflexes. They form neurological networks of connections throughout the central and peripheral nervous systems. Random and reflexive eye movements in an infant influence tone, range, and flexibility of eye motion and prepare the infant for centering. It also helps establish symmetry between upper / lower and right/left sides of the body (midline). If the midline is properly established, strabismus and amblyopia are less likely to appear because of the posture of the eyes develops in a balanced state.
2. Where is IT in space?
Centering develops subsequent to but complementary with the anti-gravity process. As the infant spends time on their tummy, lifts their head off the floor → muscles of the head/shoulders work with muscles of the eyes and the eyes begin to ‘center’ the body. Centering the eyes and visual system, moving through space, provides awareness of the me-it relationship. This me-it relationship allows us to ask ‘where is it’? Centering the body / eyes requires innervation from higher-level brain centers and is essential to developing postural control and stability. Postural stability and control allows for stability and control of fixation, pursuits, saccades, and binocularity.Once I understand where I am in space, I become aware of the things AROUND ME in space – awareness of ME-IT relationships that come from moving through space. Eyes move to an object and use binocular vision to provide depth perception – get a more precise understanding of how far away that object is in space from me. Binocularity and Depth Perception are depended upon the top two circles- to accurately point both eyes at an object, you must understand where you are and the distance between you and it. Aids in selecting an area of space for attention and directing the body, head, and eyes towards that area for information processing and spatial localization. Convergence is the oculomotor component.
3.What IS it? – Identification
Visual acuity, accommodation, visual perception. See it clearly and get meaning from what we are seeing. Deriving meaning from space selected for attention, resolution, discrimination of differences, determining relationship between details.
Initially a baby uses their tactile system to explore the world through grasping and mouthing. Once visual skills advance, the child no longer needs to touch everything in order to understand it – they simply look at an object and recognize what is is and what role it plays in the world. Here, touch can also negatively impact vision → if a touch is startling or alarming, the body goes into sympathetic overflow and interferes with visual fixation, development of accommodation and vergence control and stereopsis. As the brain matures, we learn to focus with intention. Accommodation helps a baby identify the image they are focused on and allows them to visually answer ‘what is it’? With anti-gravity, centering, and identification concurrently active → visual perceptual skills begin to develop → intersensory integration with touch, taste, sound, proprioception actively support development of visual discrimination skills.
4. What ABOUT it? Speech-Auditory / Naming
Process what is seen and communicate about it to the outside world. Permits and provides analysis and communications skills – completely unique to humans Neurons that fire together (intersensory integration), wire together → As the infant continues to develop all the senses, vision becomes the predominant sense to lead actions and conceptualize thoughts. As an infant moves into the toddler years, they make rapid advancement in expressive-language skills, which are neurologically dependent on a developed auditory and visual system – Allows us to talk about what we observe and share ideas and insights with others. The more detailed our vision, the more descriptive our language becomes → it gives vision a voice and is the verbal expression of vision. Auditory and vision systems are wired together to support a sense of comprehension, social engagement, and communication.
Intersection of the 4 circles represents VISION – which emerges at the junction of these four components Vision emerges to its fullest potential when the four sub-processes work concurrently (interdisciplinary). The 4 sub-processes begin with our primitive reflexes that build our sensorimotor system, unifies the sensory and motor systems. This critical time in their first year of life where they feel a stimulus and have a reflexive motor response to it allows for midline, oculomotor, vergence, accommodation, auditory, proprioceptive, balance, and speech development. All 4 circles are all interdependent – when they work in unison, they support vision to emerge to its fullest potential.