Iphigeneia Mariou UNED - 2010
Table of Contents
Chapter 1 Introduction Where Do Words Come From? The Origins Of A New Discipline Eye Tracking In Action
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Chapter 2 The Sense Of Vision – The Eye As A Conscious Sense-Organ The Ketchup Bottle Problem – To Look But Not To See To Fixate May Represent Attention But Not Understanding The Measurable Meaning Of The Fixations Eye Tracking Software – Is It Participant Friendly? Is Eye Tracking Affordable? Case Studies In Eye Tracking Laboratories Eye Tracking+Vision Therapy=Success At School? Learning To See: Can Dyslexia And ADHD Be Eye Tracked?
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Chapter 3 Conclusions
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Bibliography........................................................................................................................... -36 Electronic Bibliography..........................................................................................................-38 -
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“Of all the ways that humans collect information about the world around them, vision might be the most ancient, complex and important.� Andrew Parker
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INTRODUCTION It looks pink, feels soft but feels no pain, weighs less than two kilograms and is made up of 100 billion neurons. To many neurobiologists it was and still remains the most fascinating piece of solid matter in the universe. Tony Buzan claims that our brain is capable of having more ideas than the number of atoms in the known universe which is only natural if we bear in mind that the number of internal thought pathways our brain is capable of producing is 1 followed by 10.5 million kilometers of typewritten zeros (Buzan, 2003). All that, done via electrical and chemical reactions, resulting almost miraculously in our thinking, feeling, learning and comprehending the world around us. The human brain is extraordinarily singular and efficient; it only needs the amount of energy stored in two bananas to function properly on a daily basis (Howard, 1994). Curiously though, this mighty human organ has perhaps only one drawback: it is illiterate. Human beings are never born with the innate ability to read or speak, as we acquire such capacity in the course of the first few years of our lives (Novitt-Moreno, 1995). Most of us do not remember how or when we uttered our first word; it just seemed to come out so naturally that we took it for granted; while for the majority of adults, speaking and writing appear to be effortless everyday activities. No matter how natural it may have seemed to pronounce our first word as babies or spell our names for the first time at school, the learning process that resulted in these two types of communication (oral: pronouncing our first word, written: spelling our name for the first time) has been complex and elaborate. Words are not stuck on a piece of organic tissue of our brain; they are not ink, shaped in certain ways. What is it then that changes mere words from abstract and ambiguous symbols to a meaningful means of communication? WHERE DO WORDS COME FROM? THE ORIGINS OF A NEW DISCIPLINE Summer of 1951. Cornell University, USA. A pionner seminar on social sciences and research is held by a group of acknowledged scholars. Leading psychologists, linguists, sociologists and anthropologists agree jointly to describe and define a new interdisciplinary field which would explain the human ability to comprehend and
produce speech (Trevor, 2008). “Psycholinguistics” seemed to be the most precise term to delineate the nature of human language processing. Two years later, the University of Indiana, USA decided to hold a second seminar on Psycholinguistics and by 1965, Osgood and Sebeok proceeded to the editing of a survey entitled Psycholinguistics: A Survey of Theory and Research Problems which in a nutshell made public the content of the seminar that took place in Indiana (Steinberg and Sciarini, 2008). The study of the Psychology of Language (the original name for the discipline) was a reality; to establish its identity would be another matter. Initially, two schools of thought attempted to explain how language is acquired. The first view sustained that language exists because all humans have an innate capacity to it; such capacity was referred to as “universal grammar”; on the other hand, the second view argued that over the time, the human species has become aware of the social and evolutive factors that have affected and encouraged the development of spoken language (Pinker, 1994). “How does one learn to speak?” seemed to be the one million dollar question at that time. Four main theories/hypotheses were the product of such conflict: 1. The Behaviourist Theory: it states that all infants learn oral language through imitation, practice and rewards. Babies tend to imitate sounds or speech patterns, being verbally rewarded every time they do so (Skinner, 1984). Parents usually show affection and praisal to a child that has learnt to pronounce correctly, but does this necessarily mean that language development occurs only when reward is involved? Not all parents are equally attentive to their children’s needs; and not all children enjoy having a mother and a father during their first years of life. If a baby’s language learning is motivated only by rewards, then it would not be far-fetched to say that such learning process would stop automatically once the verbal reward became inexistent. 2. The Innatist Theory: it assures that babies come to this world with the biological propensity to learn a language; in other words, there exists an inborn device, built in every human called language acquisition device (LAD) that explains how children learn, invent and generate a language that they have never heard before (Baum, 2005) In other words, this theory seems to suggest that humans produce language without thinking, however would it not be correct to say that learning itself is an actual process of thinking? So if we cannot produce language without thinking, we cannot think unless we have a language? Is this -2-
what differenciates us somehow from other species? What about other factors that influence language develoment such as culture for example? I believe that language and culture are tightly interconnected (for better or worse) because the language we learn is shaped by how we categorise the world around us. Communication reveals our cultural values, heritage and perspective because as we learn language, we learn the beliefs and ideals of our culture. 3. The Cognitive Theory: caught somewhere in-between the Behaviourist and Innatist Theories, the cognitivists believe that language acquisition is a skill affected or hindered by social factors; what would be a perplex blend of the previous theories. The “black box” of the human mind should be opened and understood the cognitivist paradigm argues. The learner resembles the hard disk of a computer information processor which ought to be examined for possible data. To Richard Meyer, the originator of this theory, there are two separate channels of information located in our human brain: the auditory channel and the visual channel (Wallace, Davies and Anderson, 2007). The capacity of the channels is limited and for this reason our brain tends to follow the active process of filtering, selecting, eliminating and organising the information acquired. 4. The Social Learning Theory: Albert Bandura was the first perhaps to highlight that people learn from one another. We observe, listen, model and imitate. We use our memory, attention span and motivation to acquire knowledge, thus language (Mearns, 2009). Consequently, there are numerous physical, cognitive, linguistic and social factors that influence our learning. Does this mean that a family’s socio-economical status could affect the linguistic growth of a child? Vygotsy’s work played an important role in the development of this theory; to him, language is a fundamental tool for social interaction; The question is: do we learn language because we feel an intrinsic need to function in society? Or do we acquire language in order to survive? And what do we mean by “survive”? To be able to detect the difference between background noises and language itself? Psycholinguistics treats the study of language as something measurable directly or indirectly aiming at revealing its inner structure and function on the basis of using experimental and cognitive psychology methods. Neurobiology, neuropsychology and -3-
neurolinguistics provide the base for the study of neural and electrochemical research of the human brain and together with the cognitive sciences, they aim at achieving the three main goals of psycholinguistics (Steinberg, Nagata and Aline, 2001): •
To describe and map out all existent linguistic functions
•
To explain and more importantly to unite these functions under a neurologically acceptable (and trustable?) model of how the human brain processes language
•
To explore and examine the results of such research in order to make them plausible and comprehensible to others.
The methodology exposed above seems quite well outlined; it does not guarrantee however that its strategies and techniques of language processing examination will result to conclusive, reliable, accurate and authentic answers to the basic problems psycholinguists are encountered with. These include challenging (and somehow philosophical) topics like the ones cited below: 1. What is language? 2. What are its natural components? 3. How are these components structured, interrelated and processed? 4. How does such structure develop? 5. How does the structure support or eliminate different linguistic input and output? 6. What rules and principles determine the structure of such language process system? 7. At what level does this system operate? (linguistic, cultural, neurological, physical or genetic?) 8. How is the system affected (or not?) by external factors such brain damage or memory loss? Does psycholinguistics actually succeed in giving answers to all these controversial issues? Thomas Scovel tries to explain it indirectly when he says that even the simplest production of language is a highly complex process to analyse, let alone to comprehend (Scovel, 2000). Still though, psycholinguistics research opens a window as to how the human mind and consciousness work when it comes to language learning. How do psycholinguists search for clues and answers then? Following three rules: -4-
•
To measure directly
•
To measure with interference
•
To model
MEASURE DIRECTLY: This is a very simple (oldies and goldies) method: Just ask the subject to perform a linguistic task; control the conditions and measure how well the subject does. Example: pronounce a word, generate a verb from a noun or translate a small phrase. We need to bear in mind that linguistic tasks do not include colouring, drawing, categorising colours or remembering shapes (Scovel, 2000). Despite that, the main problem here seems to be that there exist several factors that would undoubtedly influence or hinder the findings: 1. the mental state/health, age, culture and social background of the subject (I would add “nationality” or “ethnicity” here as well) 2. the actual place where the linguistic task is taking place 3. will the subject cooperate willingly? 4. will the subject collaborate evenly throughout the whole linguistic task? 5. what happens in case of gradual refusal to carry out the task or fatigue of the subject during the task? 6. will the sex of the subject affect his/her performance, thus the result itself? How do psycholinguists control these factors? How do they deal with sudden complications during the linguistic task? Can we really create (artificially) the ideal environment, choose the ideal subject and measure unmistakenly an ideal outcome of the task in question? Perhaps we could; it would not be realistic though; it would be virtual, fake and misleading. In other words, the same linguistic task performed under the same (controllable) conditions will result into two different outcomes because it would have been undertaken by two different individuals. The task would be measurable but not precise; thus not reliable. However, let’s just consider for a second this situation as a potential exception to the rule: an extremely wealthy lady from the northern outskirts of London who’s been very well educated and lived the life of a fairytale is asked to perform the linguistic task of producing the verb “to build” from the noun “building”; on the other hand, her chauffer, a young man from Ireland, who’s only got up to KS2 at school is asked to do likewise. Both of them will give the same answer. Conclusion: social and economic status, cultural background and current employment
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do not influence the findings dramatically, except the pronunciation/accent part of the story (BritishVs. Irish). MEASURE WITH INTERFERENCE: The subjects chosen for this type of measurement are individuals that suffer from some sort of brain damage or mental deficits. They are selected on purpose because what is measured in this case is the degree of the consequences of the interference involved. Subjects are asked most of the times to do two tasks simultaneously in order for the psycholinguist to observe: •
the amount of time each individual takes to react to the task
•
the nature of judgements that the individual makes on the task
•
negative priming effects: colour names Vs. colour naming GREEN – RED
•
attentional focus or in other words eye-tracking, which is the amount of time an individual fixates on a word; eye tracking offers the chance to measure the time spent on a specific element, how often this may happen, when and why (Pinker, 1994).
MODELING: To have a pre-approved model of what a linguistic function is, helps the psycholinguist observe closer and draw meaningful conclusions, given that he/she is based and assisted by an already-made pattern of what to expect (Mearns, 2009). Sometimes though, such patterns may censure the results or obstruct the task itself. Language comprehension, production and acquisition is not a black or white issue. The parametres that influence or boost such process cannot always be pre-described in the form of a linguistic model. Sometimes we know how to perform a linguistic task correctly without knowing the rules or vice-versa. Other times we know the mechanisms of perfoming the task but we fail, even if our memory, perception and attention span are extraordinarily alert. The way we understand a lesson, read a book or hold a conversation is a multi-process function that takes place in our (illiterate) brain, as a result of intense mental activity. I believe that everyone can learn, not to the same extent though; normally, we are all born with a poweful processor with immense capacities that can perform several tasks at the same time: smelling a flower while drinking some coffee while chatting to a friend on the phone and at the same time jotting down the address of the restaurant where we will both have dinner later on. All these multi-task abilities are perhaps innate but what is really there from the very
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moment we start breathing for the first time, is the unconscious necessity to search and to find meaning through pre-defined patterns incidentally or intentionally assited by our surroundings. Just because we will never be able to open our brain to study it nor can we stick electrodes in it to examine its functions, we choose to develop less “harmful” approaches to delve into the “secrets” of the human mind; one of these approaches is called eye-tracking, the observation of people’s eye movements. And why would a psycholinguist dedicate time to monitor and record how the human eye moves when a linguistic task is performed? Because our eyes (consciously or not) go back and forth when we read a text, they look around the room when we listen, they move at different speeds when skimming through a page, they go back to re-read confusing phrases and scan the lines again and again lingering for a while on unknown words. Eye-tracking is something measurable and to a cognitive psycholinguist this fact is more than enough to start pursuing some sort of correlation between eye movements and the process of language acquisition in different situations. Now-a-days there exists trustable evidence that our eyes will move smoothly if the information they “receive” is simple to understand or familiar; they may pause if the linguistic task is tricky; they might also double back or even flit back and forth between two words or images, trying to make sense of the contradictions (Bulling et al., 2009). It all happens super-quickly, but it can be measured.
EYE TRACKING IN ACTION A pioneer French ophthalmologist was born in Paris, on May 5th, 1839. His name was Louis Émile Javal and he was the first to describe eye-movements while reading, back in the 19th century. He observed short rapid movements and short stops when an individual read through a text (Jacob and Karn, 2003); Dr. Javal had definately made his point but owing to the absence of technology he could not provide substancial evidence to back up his bold theory; besides by 1900 he had become totally blind. His findings however have been consulted on numerous occasions as they constitute a base for the modern eye-tracking methodology.
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Let’s try to get an initial idea of how eye-tracking works looking at the pictures below:
Figure 3
Figure 1
Figure 4
Figure 2
Figure 5
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What the reader can see in all of these pictures is the visual interpretation of the data gathered by an eye tracker; it is called a heat map; using a simple colour code, it indicates how an individual’s eyes travel through texts and images. Red and yellow are the areas where the visitor spent most time on; the “x” in Figure 1 indicates mouse clicks.
Figure 6
Figure 6 (http://www.hennig-thurau.de) shows the eye-tracking device itself, the model that is currently developed by the German Space Agency (Liechty, 2003). This device tells us where the readers look first and challenges psycholinguists to investigate the reason why we choose to focalise and concentrate consciously on one thing and not on another, since the human eye cannot attend to all things in a room or on a page at once. So, what this paper is going to aim at from now onwards will be •
to bring forward the eye-tracking experience and explain how and why our eyes and mind cooperate in “digesting” images, words and sounds
•
to discuss the pros and cons and contemporary issues of eye-tracking as a means of providing reliable evidence to how the human brain functions when it comes to language comprehension problems owing to visual disabilities
•
To bring forward and discuss testimonials in Eye Tracking Laboratories, where psycholinguists and behavioural optometrists use the latest software technology
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to make some sense out of eye movements during controllable situations of specific lignuistic tasks. People use their eyes to see a picture, watch a film, look at a piece of art, glance at something, catch a glimpse of someone, stare at anything eye-catching and skim or scan through a text; we peek, spot, spy, take a glander, catch sight and get an eyefull of almost all details noticeable to our naked human eyes. To make the long story short, we simply listen with our eyes; we choose non verbal communication as a path to shared meaning via emotions, feelings and thoughts. Charles Darwin used to say that all mammals show emotion reliability in their faces. Let us now measure and examine the relevance of such reliability when it comes to sending and receiving wordless messages using one’s... eyes.
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THE SENSE OF VISION THE EYE AS A CONSCIOUS SENSE-ORGAN Differenciating between foreground and background, recognising objects, singularising sizes, shapes, colours, images and orientations are only small scale examples of what the human eye is actually capable of doing. Understanding visually the world around us is a complex task far beyond the capacities of the most powerful computer, experts argue. Visual perception can be as simple or as multifaceted as converting light into ideas because the moment we begin to actually see something is the moment our eye focuses light onto the retina area (Fernald, 2006). Immediately after, light is converted into electrochemical signals distributed via cones and rods responsible for day and night vision respectively (Land and Russell, 1992). Despite the fact that the sense of vision can be fully explained neurobiologically, our human eye is also responsible for certain actions and reactions that go even further. We know how our brain decides to look at something but we ignore the reason why certain visual stimuli (images or texts) cause the eye to move from spot to spot or to linger on an element for a prolonged period of time. Such eye behaviour can be observed in the picture below: this is the recording of how one individual’s eyes have been moving back and forth on twenty-five different spots which eye tracking experts call fixations and saccades (Cornsweet, 1958).
Figure 7
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Fixations occur when our eyes linger or stop on a specific spot for some reason (or sometimes for no reason at all); fixations follow one another and they usually take place in a matter of a fraction of a second. Saccades are the movements our eyes make from one fixation to another. These movements take milliseconds. Figure 7 is an example of a gaze plot, product of an eye tracking session, where the yellow dots are fixations and the yellow lines connecting one fixation to another are saccades.
Figure 8
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Same as Figure 7, Figure 8 shows a gaze plot as well; the reader must have already spotted an obvious difference: five colours instead of one. This is because the Beijing 2008 Website was eye-tracked by five individuals, not only one. This gaze plot for the 2008 Olympics shows the online beach volleyball schedule; the organising committe wanted to know how easy or not it was to browse the website; however, the fixations and saccades of the eye tracking findings show that the website needed major improvements. The gaze plot in Figure 8 demonstrated that it had been too dificult for the participants of the eye tracking experiment to spot elementary information such as when and where the next volleyball game would be held, for example. Knowing where the participants’ fixations and saccades took place during the task of looking at the website in Figure 8, certain types of questions might arise related to the nature of the data that eye tracking can help determine: 1. Why have the participants been encountered with problems while performing the task? 2. Where they computer literate? If not, would this fact affect their performance? Shouldn’t a website be as self-explanatory and as user-friendly as possible? 3. Have the problems arisen as a result of the participants’ age, gender, cultural background or interests? 4. Were the participants expected to find problems? If so, why? 5. How have the participants read through the webpage? In detail? By scanning? 6. Has the design of the website proved helpful? 7. After looking at the schedule on the webpage, are all participants (or the majority of them) clear about where they have to go to see the first volleyball game of the 2008 Beijing Olympic Games? 8. And last but not least: Does looking at something always mean full understanding of what that “something” really means? It makes one wonder whether or not the human eye moves consciously from one fixation to another. And if so, why? How does the human brain think in order to move from one spot of interest to another? Could it be something like: “right, I’ve spent enough time looking at the logo now I have to shift my attention to the headline and then I will look back to the beach and to that attractive girl gazing the sea”? (Figure 7). It seems that the movements happen naturally (therefore unconsciously?); they are based on a general first scan of the image depending on what our brain considers interesting and worthwhile to focus attention on. Aware of these facts, Dr. Christian - 13 -
Miller, an optometric physician from New Jersey, USA decided to investigate closer both fixations and saccades to understand what may cause them. The result of his research was to find out that our brains have an in-built device similar to a biological timer so to say, that decides how often and how fast our eyes move from one scene to another. He called brain waves the shifts between two fixations and defined as brain cycles the high and low activity phases using an Electroencephalograph Scanning System. The existence of such waves was not new to Neurobiology but what Dr. Miller demonstrated was that there exists a link between focusing visual attention and memory. In other words, Dr. Miller introduced another built-in (innate?) device called metronome; the metronome, he says, dictates how we think, because the faster the brain cycles are, the faster we think. Something in our brains seems to be deciding for us; deciding on where and how to invest the milliseconds that separate one fixation from another... It is so easy to get excited about eye-tracking and its apparently promising potential. Detecting and analysing the cognitive functions of a person’s fovea fixate, the small spot on the retina responsible for detailed vision, sounds almost science fiction to everyday people. Is it really worth it though? Is it valid? Does eye-tracking provide exclusive information that no other means of measuring eye behaviour could provide? Does it possess any limitations? And if yes, could the limitations outweigh its value?
THE KETCHUP BOTTLE PROBLEM TO LOOK BUT NOT TO SEE “Consider a person staring into an open refrigerator searching for the ketchup. They may be staring directly at the bottle yet, for a variety of potential reasons, might not be paying sufficient attention to it to realize that it’s there at all. Eye tracking would tell us that this person "saw" the ketchup even though they might personally report that no ketchup was present. The risk of this scenario is that eye tracking could erroneously conclude that the user was "successful" in their task of finding the ketchup when they clearly were not.” (Jared M. Spool, CEO and Founder Principal of User Interface Engineering) http://www.uxmag.com/technology/eye-tracking
Spool lives and works in the USA. He owns a company that dedicates its time to help website designers make the best out of their online spaces. To do this, he uses eye-
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tracking technology with his clients but he does not rely exclusively on it, nor does he ackowledge eye-tracking informativity as the key to cognitive behaviour. The quote above is proof of that. Spool wants to draw our attention to one of the main drawbacks eye-tracking may possess: eye movement as linked to attention. Let’s go back to the Ketchup bottle problem and consider this situation: if the individual was eye-tracked while looking at the bottle, the information gathered, related to his/her attention span would have resulted to be everything but cognitively precise. What an eye-tracker does is to track eye movement every time attention shifts from one point to the other; however, do our eyes always reflect our focus of attention? Do we always look at what really catches our eye? Can the eye-tracker device measure something like that? It seems that the indivudual in question opens the fridge, fixates on the Ketchup bottle but does not decide to take it out of the fridge. Why not? Beacuse he/she cannot see it? But it is there! It can happen to anyone, with the Ketchup bottle, the carton of milk or the jar of jam. We know we bought such products and we are sure they are in our fridge but we just do not seem to see them even if they are sitting right in front of us. And when we get to see them, we do not realise! Why? It is called peripheral vision and this unfortunately is something that no eye-tracker could capture. Peripheral vision is everything that occurs or exists outside the very centre of gaze; since eye trackers can only track the foveal fixations, they are just not able to catch and reveal the visual field that produces the sharpest vision, the peripherical one (Cornsweet, 1958). For example, a woman’s visual-spacial intelligence thus her peripheral vision, is more accute than a man’s. This is not news to anyone. Genetists and anthropologists have always argued that men’s brains have been programmed for skills which require narrow range of vision while women possess the previledge to be able to decipher and spot a much wider spectrum of information (Fernald, 2006). It would be interesting though to know who would take less time to spot the Ketchup bottle first, a man or a woman? Consequently, eye tracking can be misleading. It cannot record out peripheral vision, that is 98% of our visual field, which is quite significant. In this case, an eye-tracker heat map or gaze plot would not represent what the subject saw; it would simply demonstrate the area or areas where attention was fixated.
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TO FIXATE MAY REPRESENT ATTENTION BUT NOT UNDERSTANDING Eye trackers have been designed to recognise and show fixations points and saccades. And this is a task they perform really well; however, they cannot tell us anything about higher-level cognitive functions such as conscious or unconscious comprehension. Just because we look at something does not imply that we make a conscious effort to understand the element of our fixation. Eye tracking data does not equal nor reveal meaningful data at least as far as the cognitive functions of our brain are concerned. On several occasions our sight must have been caught by red, breath-taking convertibles driving down the road or by incredibly attractive people walking by our side. It is important to realise that an eye tracker would only give us detailed information about where, for how long and how often we fixated our eyes on the red car or that handsome young fellow. An eye tracker could not analyse (and it is not expected to do so) mental processes such thinking and feeling. Questions like •
Why does the red convertible catch my attention?
•
Is it becasue I want one? Or because I choose to enjoy the fact that I will only be able to get a glimpse out of a car I will never have?
•
Is it the colour that I find irresistible? The design perhaps? Its speed?
•
How does it make me feel seeing it being driven fast by my side? Sad, because it is not mine? Excited, because for a millisecond I could just picture myself sitting in the driver’s seat? Indifferent, because I arrogantly feel that one day a much better car will be mine?
are not meant to be answered nor understood by an eye tracker. For this reason, the eye tracker data is not always enough; it lacks qualitative meaning. However, if the expert who uses the eye tracker to carefully observe the eye movements of a subject during a task, sat down with the subject after the eye tracking experience and discussed questions like the ones above, the complementary data could prove really valuable. Machines are able to store tons of information in their artificial memory and humans have infinite imagination which cannot be recorded, copied or tracked by any sort of software. Nonetheless, both elements (memory and imagination) could combine into a fruitful understanding of how the human brain chooses to behave under certain cognitive challenges.
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THE MEASURABLE MEANING OF THE FIXATIONS As agreed before, fixations and saccades show where but not why the subject chooses to focalise on a specific element and not on another. Looking at something may have several interpretations: 1. I look at it because I like it, I find it interesting and my eye is attracted by it 2. I look at it because I do not understand it so I have to fixate my look a little longer 3. I look at it for no reason at all, I have nothing better to do, I am just killing my time None of the three options above is measurable by any eye tracker; unless the participant him/herself gave further logical explanations, no machine could track down emotions, opinions and ideas.
EYE TRACKING SOFTWARE: IS IT PARTICIPANT FRIENDLY? How cognitively natural is it to undergo an eye tracking test session? It may sound challenging, exciting or completely unobtrusive; but is it really? It is true that eye tracking systems have evolved but still, wearing a headgear and feeling your head immobilised while looking at a computer screen is not everyone’s idea of naturalness during and an eye tracking session. Today’s eye trackers are sophisticated enough not to allow the participant know that he/she is sitting in front one (Rayner, 1998). Figure 9 shows a latest model of an eye tracker consisting of a regular computer monitor, a keyboard and a mouse. The participant is told that he/she is about to start an eye tracking session the moment the session begins. Why is this done? To avoid stressing or pre-disposing the subject? How relaxing could it be to have asubject sitting in front of a computer screen without knowing why? I would feel puzzled and before I knew, several scenarios would cross my mind as to •
what am I doing here?
•
will it hurt?
•
how long is going to take for them to tell me what is going on?
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Figure 9
Fair enough, it sounds ridiculous, but on the whole, lack of information does not relax a subject; ignoring the how, when and why of a situation does not make the situation a friendly one nor does it ensure a calm atmosphere during the eye tracking experiment. I honestly do not think that we can fool a subject in being unconscious of his /her environment. It is ackward to know that something is about to happen and to have the eye tracker expert trying to convince you that everything is (uncomfortably) normal! Shall we tell the subject then beforehand? Shall we make sure he/she knows all details and procedures before the experiment begins? To be self-conscious that one is participating in an experiment could turn out to be an adventure with little or no sense at all. Let’s picture this situation for a second: a fairly shy, introvert individual is explicitly told that he is about to participate in an eye tracking session; he knows that he will eye track an advertisement of a new sun-tan lotion. The session starts and for some reason, the young man’s shyness makes him reluctant to look at the beautiful ladies in their bathing suits enjoying the benefits of the product; the subject chooses consciously to shift his attention to the white sandy beach in the background. Once the experiment is concluded, he is asked the reason why his fixations and saccades hardly include the female presences of the advert. He decides to lie. He tells the eye tracking expert that he - 18 -
did not find the ladies attractive enough to pay any attention to. The expert has no alternative but to believe him. After all, there is no possible way he could use his eye tracker to read the subject’s mind. Potential results of the session? 1. Lack of validity 2. Lack of credibility 3. Plenty of confusion 4. The advert itself could be changed before launched to the market. Why? Because if a male subject does not find the theme attractive, the campaign designers will probably choose another way to convince about their product. 5. The advert sells the product adequately, it is attractively outlined and well thought; but nobody will know because the subject chose to lie owing to personal bias and partiality. How can we avoid all that? By eye tracking more people? Does that ensure validity and credibility? Many would say it could be a waste of time...
IS EYE TRACKING AFFORDABLE? It depends. Not everybody can afford it and it sure isn’t a cheap pastime for amateurs either. The Arrington Research (www.arringtonresearch.com) website for example, offers a lot of food for thought with prices like these:
EYE TRACKING PRODUCT
PRICE IN US DOLLARS
Camera and illuminator system
$5,698
Remote system
$7,198
Binocular remote system with presition head
$11,998
positioner Monocular System, W Series
$65,798
Binocular System, W Series
$70,798
Binocular Laptop System
$10,198
Installed Eye Tracking System
$16,998
Individual Lens For High Resolution Scene
$98
Camera Extension Cable
250$
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It is inderstood that the cost of a new – let alone complete – eye tracking system is astronomical. It is not a sophisticated toy one would pile up in the basement of his/her house and use it occasionally as if it were a Wii Balance Board or a PSP device. Of course,
one
can
rent
eye
trackers;
minimum
rental
period,
one
month;
www.objectivetechnology.com is one of the many online services that offer eye tracker glasses, computer screens and projection screens for rental, to all publics. Eye tracking software is also available. Unfortunately, prices can be up to $3,000 per day. Who buys eye trackers then? Well, customers vary from seafood and plumbing industries to advertising and marketing companies, computer software and hardware professionals in usability studies, cognition labs and optometrics associations. Adding to these significant drawbacks, eye tracking has other limitations as well: •
It takes time to design and set up eye tracking software. The actual session itself requires patience, a lot of planning and testing (Rayner, 1998). Time is money and with a low budget, eye tracking is not always the best option.
•
It is not easy to learn how to use effectively eye tracking hardware and software. It takes time to instruct someone into analysing eye tracking results; at the beginning it tends to be rather slow and the slower it gets the worse, because all data resulting from trial and error sessions is completely useless (Rayner, 1998). Experience in eye tracking comes with time; it is not a skill that can be learnt overnight.
•
What happens if the eye tracking system breaks down in the middle of a session? When we deal with technology more than one thing can go wrong at the same time.
•
Eye tracking can turn out to be so irresistable to use that it could end up being used for everything. Would eye tracking meet its purpose and value in such case? So far, http//:eyetracker.com.au an online business that sells eye tracking software and hardware, claim that the majority of their customers are fully satisfied with the validity results of their eye tracking products. The testimonials below give us some insight as to how worthwhile eye tracking has been to them:
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CASE 1 Company: Vodafone Australia Comment: eyetracker enriches website usability study for the world’s leading international mobile communications group Quote: “Our recent web usability study had an eyetracking component which gave us a richness of data that we otherwise wouldn’t have had. The result was a far deeper understanding of the strengths and weaknesses of our site, but also key potential areas for category differentiation. Eyetracker demonstrated a fantastic knowledge of eye tracking techniques and they were a pleasure to work with. From our perspective it was budget well spent and we will undoubtedly use eyetracker again for our future studies.” By: Sally Kiernan – Online Marketing Manager, Vodafone Australia
CASE 2 Company: Colmar Brunton (a market research agency) Comment: eyetracker’s customised solution helps Australia’s largest independent adhoc market research agency Quote: “I found the team at eyetracker to be extremely professional and responsive to my brief. Their flexibility in tailoring an offer to suit my needs really helped the team to deliver an outstanding approach to my client. I will definitely use eyetracker again!” By: Marilyn Murray – Group Account Director Colmar Brunton
CASE 3 Company: Couch Creative (a communication agency) Comment: Integrated marketing services agency gets competitive edge from eyetracker Quote: “I just wanted to let you know that our recent experience with eyetracker was everything it promised to be and more. The technology meets a long-standing need to understand exactly how people interact with web-based content and your expertise in interpreting these findings adds a great deal to the work of our digital design team. Not only does this improve our performance for clients but it also gives us a competitive edge. We are keen to work with you further on broader applications as opportunities arise.” By: Michael Parker – CEO Couch Creative
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These three cases appear to be solid examples of the huge effectiveness eye tracking technology had in different sectors of the marketing world. Statements like, •
“it was everything it promised and more”
•
it is a “way to understand exactly how people interact”
•
the eye tracker is “extremely professional”
•
“I will definitely use the eye tracker again!”
•
“the result was a far deeper understanding if the strengths and weeknesses of our site”
•
the eye tracker “gave us a richness of data that we otherwise wouldn’t have had”
•
the “eyetracker demonstrated a fantastic knowledge of eye tracking techniques and they were a pleasure to work with”
•
“it was budget well spent and we will undoubtedly use eyetracker again”
make one wonder whether or not a cognitive scientist would share these viewpoints as well. These people are absolutely astonished and convinced by the device itself, its results and the way it works. Perhaps it was the first time they used one and they are still unaware of certain limitations all eye tracking systems possess. Perhaps they were not looking for an in-depth cognitive study of their clients’ decision making. Or perhaps they have expressed themselves superficially, ignoring the bottom line of the story. Besides, how can one convince otherwise a person who defines the eye tracker as the only way to gather richness of data that no other resource would have been able to produce or provide. I would not like to underestimate the capacities of an eye tracker but I do believe that the statements above are somehow far-fetched, they lack precision, they seem over-generalised and suprisingly enough they only give positive feedback. Now-a-days, when we try any type of modern technology device for the first time, be it a cellphone, a microwave oven, an iPod or even a new car, we usually give both positive and negative feedback: -
I like the car but it is too expensive
-
The iPod looks perfect but it is not customer friendly; besides, its menus are everything but self-explanatory
-
This microwave is just what I have been looking for; however, I have no extra space in my kitchen
-
The cellphone is all right although its lithium battery does not last long enough for me.
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We may end up buying the product in the long run outweighing its limitations but that should not stop us from having and expressing a relative degree of satisfaction. Did these people actually knew what to use the eye tracker for? Were they absolutely clear about how far an eye tracker can take them? What the eye tracker gave them were heat maps and gaze plots; were these enough for them to fully understand their clents’ profiles and needs? Have they actually delved cognitively into the minds of the people who buy their products? Have they run some sort of evaluation feedback questionaire or survey on their clients to double check that the eye tracker’s data match the client’s point of view? Let’s see how one of the billion Vodafone customers manifests online his problems with Vodafone services, on http://www.consumercourtforum.in: -
“I am not happy with Vodafone's unlimited internet plan of Rs. 96”
-
“I am unsatisfied with their service, now they have blocked my call ... I am not able to call to customer care.”
Vodafone decides to email this client with the following comment: “We are repentant to hear for the inconvenience caused to you. Please be assured that we have taken this as a feedback and would work to improve our services to match your expectations. Thank you for your time on the call. We hope you are able to enjoy surfing internet on your Vodafone connection. Please feel free to contact us vodafonecare.pun@vodafone.com for your queries and requests. Happy to help!”
The example above does not aim to underestimate or critisize the efficacy of Vodafone services nor does it prove that all Vodafone customers are repentant to purchase and use a Vodafone mobile phone; the reason why this situation has been cited, is to highlight the nature of the reply email to the customer from Vodafone Services. Polite but vague and evasive. Has it really convinced the customer? This email is a virtual answer to a real problem. Few months ago, http://www.boxesandarrows.com/ an online business-orientated journal published in the April 2010 Issue, a couple of interesting comments about eye tracking informativity, usefullness and precision: Sonja Quirmbach: “Eye tracking provides useful addional information beside analytics and figures! It solves many questions about why user don’t click special areas on websites. There are different questions to solve and after them to do’s based of the eye tracking sessions... Eye tracking deliver also an inverse heatmap... shows the gap between the area user looked and not looked at it. The heatmaps should also checked with the analytics. Could never stand alone and always see with other tests and analytics. But need a very good preparation and concept.
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Patrick Stapleton: “This whole eye tracking thing is a big of a black box to me. Just to have an insight on how best to leverage it and approaches to understanding the results would be great.
Furthermore, and not very long ago, Bill Schroeder, a consultant at User Interface Engineering, published an article on http://www.uie.com/articles/eye_tracking_benefits/ clearly stating that: “Our recent tests showed us that eye tracking does some things well—and others not at all.” In brief, what Schroeder argues is that eye trackers can: -
“Tell whether users are even looking at the screen”
-
“Tell whether users are reading or scanning”
-
“Learn the relative intensity of user’s attention to various parts of a webpage”
-
“Determine whether a user is searching for a specific item”
-
Compare user scan patterns”
On the other hand, and always according to Schroeder, eye trackers cannot: -
“Let you know whether users actually see something”
-
“Prove that users didn’t see something”
-
“Determine why user’s are looking at something”
-
“Test everybody” : some people wear eye-glasses or contact lenses, some others smile a lot in front of the eye tracker screen; others have small pupils and wandering eyes; eye trackers do not work well under all conditions and with all types of people.
What eye trackers do is to “bounce infra-red light off a user’s eyes and follow the reflections to determine where the eyes are looking. They make it easy to collect specific data on user behavior, but interpreting the data can be an issue.” Bill Schroeder puts it quite eloquently.
Conclusively, if we know how to use eye trackers effectively, if we can afford it, if we could find the ideal subjects to test them with and if the testing occured under ideal conditions, then yes, eye tracking could provide some insight as to how our eye behaves in front of a visual stimulus. Johansen and Hansen, two Dane experts in remote evaluation in gaze typing systems, sought to answer a controversial question in their 2006
survey:
“Do
we
need
eye
trackers
to
tell
where
people
look?”
(http://usabilityprofessionals.org/upa_publications) Yes, we do. But we should not make the mistake to expect eye trackers to have a sixth sense into what the participant is doing and why. They have not been designed to psycho-analyse the participant’s mind. They report and record dry data, without any cognitive filtering at all. They are not meant to predict, identify or articulate the participant’s cognitive behaviour. Why would a machine be asked to succeed in interpreting our unconscious eye movements? It
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would be as unfair as to expect a human to perform myriads of mathematical calculations in milliseconds.
CASE STUDIES IN EYE TRACKING LABORATORIES EYE TRACKING+VISION THERAPY=SUCCEESS AT SCHOOL? Reading is a linguistic activity which the vast majority of us have performed zillion times during our school years. The characteristics of eye movement during reading have utmost significance from a psycholinguistic point of view and they are everything but unfamiliar to language behaviour experts. Such eye movements may reveal visual disorders or confirm healthy eyesight; for example, our eyes rest in fixation for approximately 200-250 milliseconds during reading (Rayner, 1998) while the chances of an individual word to be fixated are 85% if it is a content word and 35% if it is a function word (Morrison and Rayner, 1981). Eye movements also vary depending on the syntactic and conceptual difficulty of the text being read. Most of us move our eyes forward when we read but maybe none of us has ever noticed that there is a 10% of saccades that move backwards while we still think we carry on reading (Ferreira and Clifton, 1986). These types of saccadic eye movements have been named regressive saccades and are thought to be responsible for not processing the meaning of a word in a sentence, the meaning of the sentence itself or the actual syntax of the sentence. Unfortunately, in these cases not all readers always re-fixate accurately the part of the text that generated confusion (Murray and Kennedy, 1984). And this when visual disorders begin to be manifested disguised as high drop out rates in schools, lack of attention in class, lack of interest in pursuing academic goals, apparent dyslexia, ADHD and tracking problems. Let’s take a quick look at the quotes below: •
“My son was unable to read more than a few minutes at a time; his concentration was bad; his pleasure in reading was very low. His body coordination was somewhat off. We had already gone to a psychologist, neurologist, and a psychiatrist. They were only nominal help.” Isaac-16 year old with Acquired Brain Injury
•
“Alisha sometimes mixed her letters and numbers by reversing them. Also, some of her words/letters were printed backwards. I initially noted that her eyes were not tracking and aiming well.” Sam Leong, Alisha’s parent
•
“Since 2nd grade, my son has had trouble with tracking. The teachers knew about him having this problem but didn't know about eye therapy exercises that help with tracking. If there were eye exercises in school, then his tracking wouldn't have slowed him down. Fortunately, he is very smart and catches on to things very fast.” Jean R. Fisher and son
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•
“Michael had a problem with eye tracking and focus. He was not doing well in school and had problems with sports. Unfortunately, we thought he was just lazy and slow.” Liz Cheim, Michael’s parent
•
“Meagan struggled in reading, writing and math. After a year of tutoring with limited success, she was found to suffer from "eye tracking problems" and poor visual perceptual skills.” Jenny Sugiyama, Meagan’s parent
•
“When I had Paul's eyesight tested at Dr. X's office, my fears were confirmed; his eyesight was not 20/20 and there were problems. We were informed that eye tracking/eye training could be a viable alternative in lieu of wearing glasses.” Paul Ferrari, Paul’s parent
•
“I am writing my success story from a different perspective than that of a patient, or parent of a patient. I have been an educator for 45 years, functioning in such roles as a teacher, as principal and teacher simultaneously, as just a principal, and now as a director of a tutoring center. About 20 years ago, an optometrist spoke at the Home/School association meeting. His topic was vision and reading. He spoke about how eye exercises could help some children to focus better and thus read better. He stressed the importance of teachers watching children's eyes to see what they were doing as the student read. His talk definitely inspired me. It changed the way I taught. I watched what was going on, and referred many students to the eye doctor, regardless of what school vision testing said. I saw changes in some students, and none in others. The search for effective learning solutions continued.” Teacher and Educador
Where do all these testimonials come from? Can our children or pupils actually cure their visual disabilities using eye tracking technology software and become better at reading, writing and spelling? All these stories can be read online on http//:visiontherapy.org an Optometrists Network in the USA which works closely with Institutions like the American Academy of Optometry, the American Optometric Association, the College of Optometrists in Vision Develoment and the American Optometric Extension Programme. The treatment is said to be effective because it is based on direct physical therapy; no surgery, no operations, no pain. Vision Therapy Optometrists explain openly on their website, that many people who suffer from common “visual problems such as lazy eye, double vision and some learning and reading disabilities” are usually told by their personal doctors that it is too late for them to find a solution to their problem and that they have no choice, but to bear with it patiently for the rest of their lives. Vision Therapy uses a “progressive programme of vision exercises or procedures” to help patients restore the accuteness of their vision. What does eye tracking have to with all that? Simple: Optometrists diagnose visual disabilities using eye trackers; eye movement is the key or if you like, the first step to vision recovery. The patient performes the eye tracking test and depending on the results, he/she will receive two weekly sessions of thirty minutes to one hour, during - 26 -
which he/she develops or improves fundamental visual skills and abilities. The Vision Therapy team assures that all patients’ “visual comfort, ease and efficiency” changes for the better. In a nutshell, to Vision Therapy Optometrists, curing your eye sight is as simple as this three-step procedure: -
step one: eye tracking test session
-
step two: data evaluation and diagnosis
-
step three: vision care treatment and advise offered by professional optometrists
Figure 10
Figure 10 shows a picture taken during an eye tracking session by a Vision Therapy Optometrist. The subject, a young school boy, is performing a linguistic task which seems to be related with a reading exercise.
Figure 11
Figure 12
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Similar to Figure 10, Figures 11 and 12 show how young children perform reading tasks as part of their initial eye tracking session. Few years ago, journalist Carol-Anne Caroll Kral published an article online on http://www.associatedcontent.com/article/9341 , a health and wellness journal; “Rarely Tested, Eye tracking Problems Are Easily Corrected” was the title for an article that discussed the benefits of eye tracking technology as a means of reading disorders diagnosis. Caroll Kral interviewed Vickie Bockenkamp, Head of Power Tools for Learning (eye tracking software); Bockenkamp who dedicates her time in helping children and adults with learning issues states that “a standard eye exam will miss eye tracking problems” because “when you go for an eye exam, they are looking at the health of the eye only. They may not be looking at how the eye moves.” To test her clients, Bockenkamp asks them to read and track basic information on a simple printed page-text: “I look at how the eye moves, its flexibility and its ability to focus” she says. Does your child or pupil avoid schoolwork or invents excuses not to do homework? Bockenkamp believes that one of the reasons can be related to a visual disorder; when our vision seems not to adjust “readily when we look up at the blackboard and then down again to write notes” ought to be something alarming to which we need to pay attention, because our eyes need to function correctly on an individual basis and to work effectively as a team (simultaneously) on the same task.
LEARNING TO SEE: CAN DYSLEXIA AND ADHD BE EYE TRACKED? Dr. Anikar Haseloff works for the Univesity of Hohenheim in Stuttgart, Germany and has recently concluded a study on how eye tracking technology can help to identify dyslexic and ADHD children. Dr. Haseloff eye tracked visually healthy children and children suffering dyslexia and ADHD using exactly the same visual stimuli. The findings,
published
on
http://www.slideshare.net/Tobii/dyslexia-and-eye-tracking
conclude that eye tracking can definately spot problematic behaviour in a child’s eyes. As shown in Figures 13, 14, 15, 16, 17 and 18 the fixations and saccades vary dramatically among children with visual disorders and children that apparently enjoy healthy eyesight. Julian and Amina, the subjects in Figures 13 and 14 respectively,
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manage to complete successfully the visual task of following clockwise the circular lines; Julian and Amina’s visual patterns are quite even, unlike the patterns shown in Figures 15 and 16.
Figure 13: Julian, normal child, tested in school
Figure 14: Amina, normal child, tested in school
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Figure 15: Marco, suffers from dyslexia
Figure 16: Saverio, massive problems with reading
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Figure 17: Ailin, schoolgirl, no problems
Figure 18: Saverio, suffers from dyslexia
Saverio and Marco suffer from dyslexia; they have significant reading problems and their visual patterns during the visual tasks shown in Figures 15, 16 and 18 differ from Ailin’s patterns, a schoolgirl who is apparently able to fixate normally as seen in Figure 17. Despite the fact that Dr. Haseloff states that the eye tracking results gave conclusive and fundamental insight into ADHD and dyslexia diagnostics and therapy, he also highlights that one should bear in mind that children like Marco and Saverio performed the eye tracking sessions under the influence of medication; (it is not news to anyone that ADHD children are usually medicated to avoid nervousness and hyperactivity situations either in class or at home). Marco and Saverio’s gaze plots show severe reading issues spotted by the eye tracker even when the children were medicated. A similar study took place in Brunel University, London, UK; the findings published on http://www.medicalnewstoday.com/articles/18956.php were the results of an eye tracking experiment which has been perfomed on sixty-five children, aged 4-6; the - 31 -
subjects had to follow a “spot of light on a computer screen with their eyes for thirty seconds”; each time the children tried to fixate on the spot, this moved differently on purpose. The task was repeated four times for each child. The researchers at Brunel University claim to have demonstrated that children with ADHD do not have “the same type of eye movement as children without the disorder.” All this sounds promising and quite enlightening; to some it may still be science fiction while to others, a necessity. However, •
how many parents, teachers and educators are aware that eye tracking technology exists?
•
how many of them trust in the efficacy of such technology?
•
how many teachers now-a-days are qualified enough to detect visual disorder problems in their pupils with or without an eye tracker?
•
how many schools now-a-days facilitate in situ an eye tracking device?
•
how easy would it be to convince a parent that one of the first steps to visual disorder therapy is performing an eye tracking session?
•
how intrusive would such session be for the subject itself and to what extend would this affect the findings?
It is perhaps wishful thinking to say that with time, eye tracking methods will gradually become indispensable tools in the psychopaedagogic departments of every state school, that teachers will easily turn overnight into expert behavioural optometrists and that parents will authorise such activities and experiments without questioning or thinking about it twice. Children like Julian, Amina or Saverio were lucky enough to have been diagnosed in time with visual disorders which unfortunatelly go hand by hand with learning disabilities. With expert treatment and therapy these children will eventually overcome their vision problems and will undoubtedly learn to see.
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CONCLUSIONS So far, it has been made clear that eye trackers are not empathic nor intuitive technological devices developed to interpret human reasoning and behaviour by means of examining eye movement. Thus, we should not expect them to be accurate and infalible. No eye tracking software, at least in present, has been personalised nor made adaptable to the infinity of human emotions and feelings. For this reason, it is common sense to say that technology will always possess some sort of weakness no matter how highly beneficial it appears to be. Eye tracking is perhaps an unreasonably expensive way to: •
design an eye catching website
•
double check on the efficacy of webpage design
•
to get a superficial idea on what people may think about a specific product advertised online or on TV
•
to have a sample opinion on what brands are popular and which supermarket promotions or adverts have been successful
One could say that eye tracking tells you exactly what is obvious to anyone with considerable marketing experience and a small dose of insight. It is understood though, that high executives with little time, will always look for something quick and effective to scan the market with, for current tendencies and demands. And those are the ones who can afford eye tracking surveys during which most CEO’s have been convinced that they witnessed pure technology magic: a mind reading device had predicted for them their product’s future in the market. Science fiction indeeed. Eye tracking can tell you where subjects are looking but not where they are attending. No real opportunities for user feedback, incompatibility with certain people and lack of precision are in a nutshell the main disadvantages of an eye tracker: the machine that never tells you why, unless of course you interview the subject on the findings. Nonetheless, eye tracking is not completely useless. It is made useless when it is not appropriately applied. Although eye trackers are quite sophisticated and sensitive instruments, our conscious and involuntary eye movements are much faster than any eye movement recording device. Despite that, eye tracking patterns in linguistic or non linguistic tasks have managed to reveal vision disorder problems in school children whose eye behaviour and academic success has improved dramatically after vision therapy exercises. Numerous - 33 -
stories about children with visual incapacities, who were given no option other than medication and surgery, can be read online on websites like: •
http://www.visiontherapystories.org/
•
http://www.brighteyesnews.com/2010/02/17/a-vision-therapy-story
•
http://www.children-special-needs.org/vision_therapy/success_stories
•
http://www.visiontherapygroup.com/successStories.asp
These testimonials are voluntarily submitted by parents, teachers and children that enthusiastically publish their names, having told their personal experience with direct, physical vision therapy. What almost all stories have in common, is the fact that the first step to vision healing was an eye tracking session. And in this case, it was valid, not because the eye tracking data could reveal a detailed pattern of how the children’s brain behaves but because the eye tracking session confirmed without any trace of doubt, evidence of an existing visual disorder owing to peculiar eye movements. Michael Spivey, Professor of Socal Sciences, Humanities and Arts performed an interesting experiment on several participants whose eye movements were eye tracked during the session. The subjects were sat in front of four objects: a candy, a candle, a pencil and a spoon. The participants were simply instructed to pick up the candy but about a third of the time, all participants fixated on the candle before picking up the candy (Spivey and Tanenhaus, 1998). The eye tracker estimated that for a couple hundred of milliseconds each participant stopped his/her saccadic eye movement, thought twice, looked at the candle to finally pick up the candy! What is more astonishing is that all participants denied having looked at the candle at all and yet their eye movements recorded by the eye tracker had revealed that their conscious (or not) eye movement had nothing to do with the manual action of literally picking up the candy. The words “candy” and “candle” have an apparent sonoric similarity which perhaps confused for a dramatically short period of time all participants. However short it may have been though, those milliseconds were recorded by the eye tracker and helped Spivey conclude objectively in the findings of his experiment. Spivey took eye tracking technology a step further and decided to use it for another experiment. This time participants were sat in front of an apple on a towel, a towel and an empty box and were instructed to put the apple on the towel in the box. The task
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seemed easy. The eye tracker though had a different opinion. The machine recorded repetitive saccadic eye movements towards the lone towel and then a quick gaze at the apple; after that, all participants physically took the apple and placed it in the box (Spivey, Tanenhaus, Eberhard and Sedivy, 2002). It is evident that the eye tracker did not tell Spivey and his collegues that ambiguous syntax in a sentence shifts the attention of the participants to another element of focus. What the eye tracker did was to provide adequate data to lead the experts to such conclusion. Eye movements reveal the nature of spoken language comprehension and the eye tracker device is there to serve as an interactive tool towards this understanding. Why do eyes move the way they do during a cognitive activity is something that modern Neurobiology may be able to explain but will those ballictic eye movements around our visual field ever be understood in deeper neuropsychological and pshycholinguistic terms? Eye movements are the mere result of a muscular function, same as stretching our arm or wiggling our waist but they also reveal intentions, ideas, interests, emotions, opinions, memories, expectations and feelings. Eye movement is indeed a unique source of data which can be exploited but never perhaps, to its fuller extend. I believe that just because it is a real-time mental activity not even the most accurately calibrated eye tracking system could give a non theoretical asnwer as to how and why cognition is produced. It seems that we are left with no alternative but to resign ourselves to the study alone of the constant outcomes it produces.
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Bibliography Aitchison, Jean. (1998). The Articulate Mammal: An Introduction to Psycholinguistics. London: Routledge. Bulling, A. et al.: (2009). Eye Movement Analysis for Activity Recognition, Proc. of the 11th International Conference on Ubiquitous Computing, Orlando, United States, (September 2009) Cornsweet, TN. (1958). New technique for the measurement of small eye movements. JOSA 48, 808–811. F. Ferreira and Jr. Clifton, C. (1986). The independence of syntactic processing. Journal of Memory and Language, 25:348-368. Fernald, Russell D. (2006). "Casting a Genetic Light on the Evolution of Eyes". London: Routledge. Findlay and Gilchrist. (2003). “Active Vision -- The Psychology of Looking and Seeing”. Oxford: Oxford University Press Harley, Trevor. (2008). The Psychology of Language: From data to theory (3rd. ed.) Hove: Psychology Press Hart, Leslie A. (1983). Human Brain, Human Learning. NY: Longman. Hooker, Judith and Dick Teresi. (1986) 3-Pound Universe. NY: Macmillan. Howard, Pierce J. (1994). The Owner's Manual for the Brain: Everyday Applications from Mind-Brain Research. Austin, Texas: Bard Jacob, R. J. K. & Karn, K. S. (2003). Eye Tracking in Human-Computer Interaction and Usability Research: Ready to Deliver the Promises. In R. Radach, J. Hyona, & H. Deubel (eds.), The mind's eye: cognitive and applied aspects of eye movement research Boston: North-Holland/Elsevier. Just MA, and Carpenter PA. (1980). A theory of reading: from eye fixation to comprehension. Psychol Rev 87:329–354 Kennedy, A. & Murray, W.S. (1984). Reading without eye movements. In A.G. Gale & C.W. Johnson (Eds.). Theoretical and Applied Aspects of Eye Movement Research. Amsterdam: North Holland. Kotulak, Ronald. (1996). Inside the Brain: Revolutionary Discoveries of How the Mind Works. Kansas City, MO, USA: Andrews and McMeel Liechty, J. Pieters, R & Wedel, M. (2003). The Representation of Local and Global Exploration Modes in Eye Movements. Oxford: OUP
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Mearns, J. (2009). Social learning theory. In H. Reis & S. Sprecher (Eds.), Encyclopedia of human relationships (vol. 3) (pp. 1537-1540). Thousand Oaks, CA, USA: Sage. Morrison, R. E., & Rayner, K. (1981). Saccade size in reading depends upon character spaces and not visual angle. Perception & Psychophysics, 30, 395-396. Novitt-Moreno, Anne. (1995). How Your Brain Works. Emeryville, CA, USA: ZiffDavis. Parker, Andrew. (2003). In the Blink of an Eye: How Vision Sparked the Big Bang of Evolution. Cambridge, MA: Perseus Pinker, Steven. (1994). The Language Instinct. New York: William Morrow Rayner, K. (1998). Eye movements in reading and information processing: 20 years of research. Psychological Bulletin, 124, 372–422. Rayner, K. and Pollatsek, A. (1989) The Psychology of Reading. New York: Prentice Hall. Scovel, Thomas. (2000). A critical review of the critical period research : Annual Review Of Applied Linguistics 20. 213-23 Seidner, Stanley S. (1982). Ethnicity, Language, and Power from a Psycholinguistic Perspective. Bruxelles: (Centre de recherche sur le pluralinguisme) Skinner, B.F. (1984). Behavioral and Brain Sciences. New York: Bard Spivey, M.J. Tanenhaus, M.K, Eberhard K.M., Sedivy J.C. (2002). Eye movements and spoken language comprehension: Cognitive Psychology, 45, 447-481. Spivey, M.J., and Tanenhaus, M.K. (1998). Effects of visual context on syntactic ambiguity resolution: Cognitive Psychology Journal, 45, 447-481 Steinberg, Danny D. & Sciarini, Natalia. (2006). Introduction to Psycholinguistics 2nd Edition. London: Longman. Steinberg, Danny D., Hiroshi Nagata, and David P. Aline, ed. (2001) Psycholinguistics: Language, Mind and World, 2nd ed. London: Longman Tony Buzan, (2000). Use Your Head. London: BBC Consumer Publishing. Tony Buzan, (2003). The Mind Map Book: Radiant Thinking - Major Evolution in Human Thought. London: BBC Cunsumer Publishing. Wallace, B ., Ross, A., Davies, J.B., and Anderson T., (eds) (2007) The Mind, the Body and the World: Psychology after Cognitivism. London: Imprint Academic.
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Electronic bibliography •
http://www.verticalmeasures.com/search-optimization (Figures 1 and 2)
•
http://eyetracking.me (Figures 3, 4 and 5)
•
http://www.hennig-thurau.de/photos3.html (Figure 6)
•
http://www.eyetracking.com.ua/eng/visualization (Figure 7)
•
http://www.uxmatters.com/mt/archives/2009 (Figure 8)
•
http://www.mpi.nl/world/tg/eye-tracking (Figure 9)
•
http://www.visiontherapy.org (Figures 10, 11 and 12)
•
http://www.slideshare.net/Tobii/dyslexia-and-eye-tracking (Figures 13, 14, 15, 16, 17 and 18)
•
http://www.uxmag.com/technology/eye-tracking
•
www.arringtonresearch.com
•
www.objectivetechnology.com
•
http//:eyetracker.com.au
•
http://www.consumercourtforum.in
•
http://www.boxesandarrows.com
•
http://www.uie.com/articles/eye_tracking_benefits/
•
http://usabilityprofessionals.org/upa_publications
•
http://www.associatedcontent.com/article/9341
•
http://www.medicalnewstoday.com/articles/18956.php
•
http://www.brighteyesnews.com/2010/02/17/a-vision-therapy-story
•
http://www.children-special-needs.org/vision_therapy/success_stories
•
http://www.visiontherapygroup.com/successStories.asp
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