So another part of the dyslexia constellation is vision. And this is an intriguing connection between vision and reading because obviously many conceptions of dyslexia are that it is primarily a visual problem. And this is certainly when dyslexia was first described scientifically, around the turn of the century, it was definitely the visual symptoms that were commonly reported. But what the current conceptualization of dyslexia is now that actually the visual part of the constellation is not typically the primary cause. Although, for some people it can be an almost equal part of the profile causing significant problems. But as we talked about in the audition segment, vision, even though it sounds like a nice simple two syllable word, is an incredibly complex process. So trying to work out exactly where either the level of breakdown or where the interaction with phonology is happening, is an incredibly difficult task. And so again, a large army of researchers over decades have been trying to refine our knowledge of this connection. And certainly our knowledge is advancing rapidly, although we don't have the whole picture yet. And so I'm going to talk about, just mentioned some of the main kind of approaches towards vision that you may encounter in the current time. So one line of inquiry has looked at the role of visual stress in relation to dyslexia. So this is the idea that for some people with dyslexia, there's a specific problem in seeing highly contrastive symbols upon, so for example, black characters on a very white background. And the contrast sensitivity here is for some people high levels of contrast, are really hard in terms of then processing the text in a meaningful way. So this is one approach that's more discussed in Europe, in the UK, as opposed to the USA. But the raw, the accompanying remediation technique for this is providing people with either covered lenses on their glasses cut with colors, sometimes individualized for the individual person's kind of contrast sensitivity. Or colored overlays that can go over a highly contrastive text, the scene to reduce the amount of visual stress. And so individuals have definitely reported benefits from these interventions. Although, the research evidence and the evidence based behind them is still a bit mixed in terms of the efficacy across the broad group of people with dyslexia. Another approach that's being taken is looking at possible underlying neural causes. And so there's a theory called the Magnocellular theory, which is a comprehensive theory which really takes the eye movements and motion perception difficulties that some people with dyslexia report, and really look at what might be the underlying mechanisms there. Again, although in many ways this makes intuitive sense, the evidence basis is slightly mixed in this area. So we don't know whether this is a cause or effect for people with dyslexia. And then another area of vision that's actually received a lot of attention in the last few years, is the idea of visual attention. So here we're talking about clearly a process that is quite removed from the peripheral activities of visual processing at the eye level. And this is a much more cognitive level of processing, where the brain is really deciding, what do I attend to. Although, a very subconscious level. You're not aware of these decisions as it's happening. But there's been some convincing evidence, especially from a researcher in Italy called Facoetti suggesting that actually this high level of visual processing, there may be issues again for a proportion of people with dyslexia. And to actually look at this in more detail, I worked with my close collaborator, Dr. Matthew Schneps at Harvard, and we were looking at visual attention in a group of secondary school students in America. And the way that we looked at this, was actually to hypothesize that if aspects of visual attention are a key problem for you, you might actually find it easier to read with a smaller window of text. And so we actually contrasted students reading fairly considerable lengths of text on a smartphone device, which is a small window of text, compared to a tablet sized device, which is a bit larger and has the same kind of electronic motivation as well as some traditional straightforward paper. And we did find that for a subgroup of students who had a reduced visual span, so how much they could attend to in a short amount of time visually. They were actually comprehending better and showing a greater reading fluency on the smartphone. So this is intriguing. It's important with this finding though, to realize that we had the interaction effect which means the students of slightly higher ability, actually reading on the smartphone was actively unhelpful. So this isn't a piece of advice we can just give to everyone. And I think some of you in the audience may have a feeling actually for you or other people you know, reading on a smartphone can actually feel quite uncomfortable and quite a hindrance to comprehension. So I think that actually technology is interesting in this regard because it actually gives us many new visual affordances in ways that we can manipulate text visually. And so I think actually, it's a critical time for vision researchers looking at reading and dyslexia, because I think we have a big task on our hands to work out for different individuals. What's the ultimate kind of visual presentation of text that's going to be ideal? And I think all of us vary in our visual perceptual strengths and weaknesses. And so for all of us, there's going to be an interesting interaction there and we may find certain presentations of text easier or harder. So this is going to be something to look out for in the future and it may really impact the relationship between readers and text.
