In these silent times, I've aught but some more essays to share with you. This one I submitted to the Daily Telegraph Science Writer contest:
Our eyes, windows to our soul, are not one-way streets. Our mental life, irrigated by our perception, depends on the images illuminating it. This simple metaphor for our vision, a matter more complex than our blunt portholes, sheds light on the mental condition of autism. We recognize people with autism by the trouble they show in socializing, their language deficiencies and their insistence on sameness and repetition. But a less well-known fact is that they see the world rather differently from the rest of us, a fact that can allow us to understand and aid them.
Sight starts in the eyes, as does the crux of the matter according to psychologists Kate Plaisted and Greg Davis. They argue the key to understanding this is the magnocellular (MC) system of cells in the retina. MC cells respond to coarse, global features, and brief changes in the visual fringe, making them vital in guiding attention to salient aspects of our surroundings. Dr's Plaisted and Davis have shown that these cells are less sensitive in autistic individuals, which can explain two outcomes related to the properties of these cells. Firstly, children with autism easily concentrate on the fine aspects of scenes, helping them to quickly spot slight changes and making them impervious to visual illusions; but have trouble grasping the gross context of a scene. Secondly, they find it hard to move their attention from one thing to the next, which explains their tendency toward reiteration.
Also, this MC deficit may cause a domino effect on social brain functions like face perception or imitation. We start watching faces in our infancy, an ability depending on our MC system, which directs our attention to the archetypal, gross t-shaped form of the human face. This focus seeds the growth of our adult abilities, and disturbing it mars our natural tendency to respond to social hints, resulting in severe social difficulties. Mark Johnson argues this MC system is also critical in adulthood, by helping us comprehend face expressions which cause global visual changes. Facial gestures are the physical twins of emotion, that very abstract concept that lets us make sense of not only our own, but also others' mental world.
The MC system also feeds into the so called dorsal visual stream in the brain that underlies such processes as perception of coherent motion, also impaired in autism. This in turn impairs our perception of other people's actions and our ability to imitate them. Indeed, in this dorsal stream, 'mirror neurons' respond to actions we see others do and those we make ourselves. This allows us to cross the frontier between self and other, not only in terms of imitating acts but also mental states, letting us understand others and share our happiness or pain with them. Hence, according to Marco Iacoboni and Mirella Dapretto, it is a deficit in this system that leads to problems in imitation and empathy in autism.
Lastly, autistic people don't perceive objects in the way we do. Sarah Grice showed that they don't show the same characteristic electrical brain activity when seeing illusory objects, like the Kanisza square (see above image), as normal individuals do. Instead, they respond like 6-month-old infants who can't yet integrate the display into a square, making their visual world fragmented, stopping them from seeing the forest from the trees. Crucially, since our interactions depend on the big picture - exuberant dancing and loud singing may make us the spirit of a party but will land us in detention if we try it at school during an exam - it's not surprising that an inability to judge context can be socially crippling.
So what if autism is all about vision, or lack thereof? Well, this understanding will hone our own foresight and help tackle the root problems in autism, letting us intervene sooner by using MC sensitivity as an early diagnostic tool. Our knowledge can also focus our intervention schemes at the visual problems and their developmental consequences, particularly since brain plasticity and flexibility is greatest in infancy. For instance, we could engage infants at risk in educational games that require quick shifts of attention and binding of features together. Or, perhaps, educate them to focus on and recognize faces and their expressions, even train their mirror neurons through imitative play. By learning how they see the world and how we can help them see ours, we can make life easier for these our children, the apples of our eyes.
Sight starts in the eyes, as does the crux of the matter according to psychologists Kate Plaisted and Greg Davis. They argue the key to understanding this is the magnocellular (MC) system of cells in the retina. MC cells respond to coarse, global features, and brief changes in the visual fringe, making them vital in guiding attention to salient aspects of our surroundings. Dr's Plaisted and Davis have shown that these cells are less sensitive in autistic individuals, which can explain two outcomes related to the properties of these cells. Firstly, children with autism easily concentrate on the fine aspects of scenes, helping them to quickly spot slight changes and making them impervious to visual illusions; but have trouble grasping the gross context of a scene. Secondly, they find it hard to move their attention from one thing to the next, which explains their tendency toward reiteration.
Also, this MC deficit may cause a domino effect on social brain functions like face perception or imitation. We start watching faces in our infancy, an ability depending on our MC system, which directs our attention to the archetypal, gross t-shaped form of the human face. This focus seeds the growth of our adult abilities, and disturbing it mars our natural tendency to respond to social hints, resulting in severe social difficulties. Mark Johnson argues this MC system is also critical in adulthood, by helping us comprehend face expressions which cause global visual changes. Facial gestures are the physical twins of emotion, that very abstract concept that lets us make sense of not only our own, but also others' mental world.
The MC system also feeds into the so called dorsal visual stream in the brain that underlies such processes as perception of coherent motion, also impaired in autism. This in turn impairs our perception of other people's actions and our ability to imitate them. Indeed, in this dorsal stream, 'mirror neurons' respond to actions we see others do and those we make ourselves. This allows us to cross the frontier between self and other, not only in terms of imitating acts but also mental states, letting us understand others and share our happiness or pain with them. Hence, according to Marco Iacoboni and Mirella Dapretto, it is a deficit in this system that leads to problems in imitation and empathy in autism.
Lastly, autistic people don't perceive objects in the way we do. Sarah Grice showed that they don't show the same characteristic electrical brain activity when seeing illusory objects, like the Kanisza square (see above image), as normal individuals do. Instead, they respond like 6-month-old infants who can't yet integrate the display into a square, making their visual world fragmented, stopping them from seeing the forest from the trees. Crucially, since our interactions depend on the big picture - exuberant dancing and loud singing may make us the spirit of a party but will land us in detention if we try it at school during an exam - it's not surprising that an inability to judge context can be socially crippling.
So what if autism is all about vision, or lack thereof? Well, this understanding will hone our own foresight and help tackle the root problems in autism, letting us intervene sooner by using MC sensitivity as an early diagnostic tool. Our knowledge can also focus our intervention schemes at the visual problems and their developmental consequences, particularly since brain plasticity and flexibility is greatest in infancy. For instance, we could engage infants at risk in educational games that require quick shifts of attention and binding of features together. Or, perhaps, educate them to focus on and recognize faces and their expressions, even train their mirror neurons through imitative play. By learning how they see the world and how we can help them see ours, we can make life easier for these our children, the apples of our eyes.
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