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Naturalistic reading paradigms and stimuli consisting of long continuous texts are essential for characterizing the cortical basis of reading. Due to the highly dynamic nature of the reading process, electrophysiological brain imaging methods with high spatial and temporal resolution, such as magnetoencephalography (MEG), are ideal for tracking them. However, as electrophysiological recordings are sensitive to electromagnetic artifacts, data recorded during naturalistic reading is confounded by ocular artifacts. In this study, we evaluate two different pipelines for removing ocular artifacts from MEG data collected during continuous, naturalistic reading, with the focus on saccades and blinks. Both pipeline alternatives are based on blind source separation methods but differ fundamentally in their approach. The first alternative is a multi-part process, in which saccades are first extracted by applying Second-Order Blind Identification (SOBI) and, subsequently, FastICA is used to extract blinks. The other alternative uses a single powerful method, Adaptive Mixture ICA (AMICA), to remove all artifact types at once. The pipelines were tested, and their effects compared on MEG data recorded from 13 subjects in a naturalistic reading task where the subjects read texts with the length of multiple pages. Both pipelines performed well, extracting the artifacts in a single component per artifact type in most subjects. Signal power was reduced across the whole cortex in all studied frequency bands from 1 to 90 Hz, but especially in the frontal cortex and temporal pole. The results were largely similar for the two pipelines, with the exception that SOBI-FastICA reduced signal in the right frontal cortex in all studied frequency bands more than AMICA. However, there was considerable interindividual variation in the effects of the pipelines. As a holistic conclusion, we choose to recommend AMICA for removing artifacts from MEG data on naturalistic reading but note that the SOBI-FastICA pipeline has also various favorable characteristics.

Central questions in the study of visual word recognition and developmental dyslexia are whether early lexical activation precedes and supports decoding (a dual-stage view) or not (dual-route view), and the locus of deficits in dysfluent reading. The dual-route view predicts early word frequency and length interaction, whereas the dual-stage view predicts word frequency effect to precede the interaction effect. These predictions were tested on eye movements data collected from (n = 152) children aged 9–10 among whom reading dysfluency was overrepresented. In line with the dual-stage view, the results revealed an early word frequency effect in first fixation duration followed by robust word length effect in refixation probability and an interaction of word frequency and word length in summed refixation duration. This progression was advanced in fluent reading to be observable already in first fixation duration. Poor reading fluency was mostly explained by inflated first fixation durations, and to stronger word frequency and length effects in summed refixation duration. This pattern of results suggests deficits in early letter encoding and slowness in serial grapheme-phoneme conversion. In contrast to the widely held belief, the holistic orthographic processing of words seemed to be intact.

This study investigated teachers’ focus of attention and stress in first-grade classrooms. Teachers’ (n = 53) focus of attention was recorded in fall and spring with a mobile eye-tracking device, and the teachers reported stress via questionnaires. Correlation analysis was used to examine association between teacher stress (exhaustion, cynicism, and inadequacy) and focus of attention. Then, one teacher reporting more stress and one reporting less stress were selected for a case study to examine variations in their focus of attention. The results showed positive associations between teachers’ perceived inadequacy and overall focus of attention (whole eye-tracking recording) both in fall and spring. Teachers’ focus of attention during specific activity settings of management/routines and transitions correlated positively with all three stress domains in fall. In addition, a positive association was also found between teacher inadequacy and focus of attention during teacher-directed large group activity setting. peerReviewed

Depressed individuals exhibit an attentional bias towards mood-congruent stimuli, yet evidence for biased processing of threat-related information in human interaction remains scarce. Here, we tested whether an attentional bias towards interpersonally aggressive pictures over interpersonally neutral pictures could be observed to a greater extent in depressed participants than in control participants. Eye movements were recorded while the participants freely viewed visually matched interpersonally aggressive and neutral pictures, which were presented in pairs. Across the groups, participants spent more time looking at neutral pictures than at aggressive pictures, probably reflecting avoidance behaviour. When the participants could anticipate the stimulus valence, depressed participants – but not controls – showed an early attentional bias towards interpersonally aggressive pictures, as indexed by their longer first fixation durations on aggressive pictures than on neutral pictures. Our results thus preliminarily suggest both an early attentional bias towards interpersonal aggression, which is present, in depressed participants, also when aggression contents are anticipated, and a later attentional avoidance of aggression. The early depression-related bias in information processing may have maladaptive effects on the way depressed individuals perceive and function in social interaction and can therefore maintain depressed mood. peerReviewed

The associations among readers’ cognitive skills (general cognitive ability, reading skills, and attentional functioning), task demands (easy versus difficult questions), and process measures (total fixation time on relevant and irrelevant paragraphs) was investigated to explain task-oriented reading accuracy and efficiency (number of scores in a given time unit). Structural equation modeling was applied to a large dataset collected with sixth-grade students, which included samples of dysfluent readers and those with attention difficulties. The results are in line with previous findings regarding the dominant role of general cognitive ability in the accuracy of task-oriented reading. However, efficiency in task-oriented reading was mostly explained by the shorter viewing times of both paragraph types (i.e., relevant and irrelevant), which were modestly explained by general cognitive ability and reading fluency. These findings suggest that high efficiency in task orientation is obtained by relying on a selective reading strategy when reading both irrelevant and relevant paragraphs. The selective reading strategy seems to be specifically learned, and this potentially applies to most students, even those with low cognitive abilities.

Dyslexia is a common neurocognitive learning disorder that can seriously hinder individuals’ aspirations if not detected and treated early. Instead of costly diagnostic assessment made by experts, in the near future dyslexia might be identified with ease by automated analysis of eye movements during reading provided by embedded eye tracking technology. However, the diagnostic machine learning methods need to be optimized first. Previous studies with machine learning have been quite successful in identifying dyslexic readers, however, using contrasting groups with large performance differences between diagnosed and good readers. A practical challenge is to identify also individuals with borderline skills. Here, machine learning methods were used to identify individuals with low performance of reading fluency (below 10 percentile from a normal distribution) using their eye movement recordings of reading. Random Forest was used to select most important eye movement features to be used as input to a Support Vector Machine classifier. This hybrid method was capable of reliably identifying dysfluent readers and it also provided insight into the data used. Our best model achieved accuracy of 89.7% with recall of 84.8%. Our results thus establish groundwork for automatic detection of dyslexia in a natural reading situation. peerReviewed

Participants' eye movements and electroencephalogram (EEG) signal were recorded as they read sentences displayed according to the gaze-contingent boundary paradigm. Two target words in each sentence were manipulated for lexical frequency (high vs. low frequency) and parafoveal preview of each target word (identical vs. string of random letters vs. string of Xs). Eye movement data revealed visual parafoveal-on-foveal (PoF) effects, as well as foveal visual and orthographic preview effects and word frequency effects. Fixation-related potentials (FRPs) showed visual and orthographic PoF effects as well as foveal visual and orthographic preview effects. Our results replicated the early preview positivity effect (Dimigen, Kliegl, & Sommer, 2012) in the X-string preview condition, and revealed different neural correlates associated with a preview comprised of a string of random letters relative to a string of Xs. The former effects seem likely to reflect difficulty associated with the integration of parafoveal and foveal information, as well as feature overlap, while the latter reflect inhibition, and potentially disruption, to processing underlying reading. Interestingly, and consistent with Kretzschmar, Schlesewsky, and Staub (2015), no frequency effect was reflected in the FRP measures. The findings provide insight into the neural correlates of parafoveal processing and written word recognition in reading and demonstrate the value of utilizing ecologically valid paradigms to study well established phenomena that occur as text is read naturally. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

This study sought to assess the representational format of task options in the representational variant of the force concept Inventory (R-FCI) test, namely its impact on students’ problem-solving approaches. This was done with the help of eye-tracking equipment. 35 high-school students solved four tasks, mainly from the R-FCI test, which sought to assess the student’s understanding of Newton’s 1st and 2nd Law of Motion. As they were trying to solve the problems, their gazes were tracked by TobiiTX300. A comparison between students who provided the correct and incorrect answer was subsequently carried out. The correctly answering students very quickly found the correct solution both in verbal and graph representation. For motion map representation, they usually compared and made decision between two options. The incorrectly answering students did not show any consistent strategy except they paid the least attention to the correct answer. Moreover, two case stud studies of correctly and incorrectly answering students were described. Studie se zabývá zjišťováním efektu formátu reprezentace nabízených alternativ v didaktickém testu R-FCI zaměřeném na porozumění 1. a 2. Newtonovu zákonu za pomoci oční kamery. 35 žáků SŠ řešilo 4 úlohy převážně z výše uvedeného testu a při tomto řešení byly zaznamenávány jejich oční pohyby kamerou Tobii TX300. Na základě výsledků řešení úloh byly porovnány skupiny správně a nesprávně řešících žáků. Žáci, kteří řešili danou úlohu správně, pro grafickou a verbální reprezentaci našli odpověď velmi rychle. V případě zobrazení pohybu v časovém diagramu se obvykle rozhodovali mezi dvěma možnostmi. U žáků řešících úlohu nesprávně jsme pozorovali v téměř všech případech nejmenší zaměření pozornosti právě na správnou alternativu. Dvě případové studie správně a nesprávně odpovídajících dvou žáků jsou uvedeny pro detailnější zachycení jejich rozdílných strategií. peerReviewed

Eye-tracking technology was used to examine Internet search result evaluation strategies adopted by sixth-grade students (N = 36) during ten experimental information search tasks. The relevancy of the search result’s title, URL, and snippet components was manipulated and selection of search results as well as looking into probabilities on the search result components was analysed. The results revealed that during first-pass inspection, students read the search engine page by first looking at the title of a search result. If the title was relevant, the probability of looking at the snippet of the search result increased. During second-pass inspection, there was a high probability of students focusing on the most promising search result by inspecting all of its components before making their selection. A cluster analysis revealed three viewing strategies: half of the students looked mainly at the titles and snippets; one-third with high probability examined all components; and one-sixth mainly focused on titles, leading to more frequent errors in search result selection. The results indicate that students generally made a flexible use of both eliminative and confirmatory evaluation strategies when reading Internet search results, while some seemed to not pay attention to snippet and URL components of the search results. peerReviewed

Recent research has revealed enhanced autonomic and subjective responses to eye contact only when perceiving another live person. However, these enhanced responses to eye contact are abolished if the viewer believes that the other person is not able to look back at the viewer. We purported to investigate whether this "genuine" eye contact effect can be reproduced with pre-recorded videos of stimulus persons. Autonomic responses, gaze behavior, and subjective self-assessments were measured while participants viewed pre-recorded video persons with direct or averted gaze, imagined that the video person was real, and mentalized that the person could see them or not. Pre-recorded videos did not evoke similar physiological or subjective eye contact effect as previously observed with live persons, not even when the participants were mentalizing being seen by the person. Gaze tracking results showed, however, increased attention allocation to faces with direct gaze compared to averted gaze directions. The results suggest that elicitation of the physiological arousal in response to genuine eye contact seems to require spontaneous experience of seeing and of being seen by another individual.

Both eye tracking and motion capture technologies are nowadays frequently used in human sciences, although both technologies are usually used separately. However, measuring both eye and body movements simultaneously would offer great potential for investigating cross- modal interaction in human (e.g. music and language-related) behavior. Here we combined an Ergoneers Dikablis head mounted eye tracker with a Qualisys Oqus optical motion cap- ture system. In order to synchronize the recordings of both devices, we developed a gener- alizable solution that does not rely on any (cost-intensive) ready-made / company-provided synchronization solution. At the beginning of each recording, the participant nods quickly while fixing on a target while keeping the eyes open – a motion yielding a sharp vertical displacement in both mocap and eye data. This displacement can be reliably detected with a peak-picking algorithm and used for accurately aligning the mocap and eye data. This method produces accurate synchronization results in the case of clean data and therefore provides an attractive alternative to costly plug-ins, as well as a solution in case ready-made synchronization solutions are unavailable.

This study used eye-tracking to capture students' visual attention while taking a test of understanding graphs in kinematics (TUG-K). A total of N = 115 upper-secondary-level students from Germany and Switzerland took the 26-item multiple-choice instrument after learning about kinematics graphs in the regular classroom. Besides choosing the correct alternative among research-based distractors, the students were required to judge their response confidence for each question. The items were presented sequentially on a computer screen equipped with a remote eye tracker, resulting in a set of approx. 3000 paired responses (accuracy and confidence) and about 40 h of eye-movement data (approx. 500 000 fixations). The analysis of students' visual attention related to the item stems (questions), and the item options reveal that high response confidence is correlated with shorter visit duration on both elements of the items. While the students' response accuracy and their response confidence are highly correlated on the score level, r(115) = 0.63, p < 0.001, the eye-tracking measures do not sufficiently discriminate between correct and incorrect responses. However, a more fine-grained analysis of visual attention based on different answer options reveals a significant discrimination between correct and incorrect answers in terms of an interaction effect: incorrect responses are associated with longer visit durations on strong distractors and less time spent on correct options while correct responses show the opposite trend. Outcomes of this study provide new insights into the validation of concept inventories based on the students' behavioural level., European Journal of Physics, 41 (2), ISSN:0143-0807, ISSN:1361-6404

Recent studies on gaze behaviours in individuals with autism spectrum disorder (ASD) have utilised “live eye tracking.” Such research has focused on generating quantitative eye tracking measurements, which provide limited (if any) qualitative contextual details of the actual interactions in which gaze occurs. This article presents a novel methodological approach that combines live eye tracking with qualitative interaction analysis, multimodally informed conversation analysis. Drawing on eye tracking and wide-angle video recordings, this combination renders visible some of the functions, or what gaze “does,” in interactional situations. The participants include three children with ASD and their adult co-participants during body-movement gaming sessions. The article demonstrates how quantitative eye tracking research can be extended qualitatively using a microanalytic interaction analysis to recontextualise the gaze shifts identified. The findings in this article show that the co-participants treat a child’s gaze shifts differently depending on when these occur in a stream of other action. The study suggests that introducing this qualitative dimension to eye tracking research could increase its ecological validity and offer new insight into gaze behaviours in ASD. peerReviewed

This large-scale eye-movement study (N = 164) investigated how students read short task assignments to complete information search problems and how their cognitive resources are associated with this reading behavior. These cognitive resources include information searching subskills, prior knowledge, verbal memory, reading fluency, and attentional difficulties. In this study, the task assignments consisted of four sentences. The first and last sentences provided context, while the second or third sentence was the relevant or irrelevant sentence under investigation. The results of a linear mixed-model and latent change score analyses showed the ubiquitous influence of reading fluency on first-pass eye movement measures, and the effects of sentence relevancy on making more and longer reinspections and look-backs to the relevant than irrelevant sentence. In addition, the look-backs to the relevant sentence were associated with better information search subskills. Students with attentional difficulties made substantially fewer look-backs specifically to the relevant sentence. These results provide evidence that selective look-backs are used as an important index of comprehension monitoring independent of reading fluency. In this framework, slow reading fluency was found to be associated with laborious decoding but with intact comprehension monitoring, whereas attention difficulty was associated with intact decoding but with deficiency in comprehension monitoring. peerReviewed

Musicians often use mental practice for enhancing performance, but individuals may have different preferences and skills in their characteristic, individually successful ways of carrying out such practice. In this study, we focus on the approaches to mental practice of four pianists who, according to the ratings of a panel of expert judges, showed outstanding improvement in their performances following their mental practice of a new piece in at least one of the two conditions: silent reading of the score or reading the score while simultaneously listening to the music. The four pianists’ approaches to mental practice were studied through self-reports in post-task interviews that were compared with eye-tracking data gathered during the actual mental practice. In successful mental practice, the pianists relied on their experience and the skills they had practised in audiation, use of recordings, imaginary rehearsal, and structural analysis. The results encourage musicians to explore their characteristic approaches to mental practice, and to deliberately practise and develop versatile mental practice skills in order to apply them flexibly in different musical situations. Eye tracking was found to be a useful tool for validating and supplementing musicians’ subjective self-descriptions and for revealing covert mental processes in the context of music reading. peerReviewed

The competent handling of representations is required for understanding physics' concepts, developing problem-solving skills, and achieving scientific expertise. Using eye-tracking methodology, we present the contributions of this paper as follows: We first investigated the preferences of students with the different levels of knowledge; experts, intermediates, and novices, in representational competence in the domain of physics problem-solving. It reveals that experts more likely prefer to use vector than other representations. Besides, a similar tendency of table representation usage was observed in all groups. Also, diagram representation has been used less than others. Secondly, we evaluated three similarity measures; Levenshtein distance, transition entropy, and Jensen-Shannon divergence. Conducting Recursive Feature Elimination technique suggests Jensen-Shannon divergence is the best discriminating feature among the three. However, investigation on mutual dependency of the features implies transition entropy mutually links between two other features where it has mutual information with Levenshtein distance (Maximal Information Coefficient = 0.44) and has a correlation with Jensen-Shannon divergence (r(18313) = 0.70, p

The idea behind gaze interaction using Pursuits is to leverage the human's smooth pursuit eye movements performed when following moving targets. However, humans can also anticipate where a moving target would reappear if it temporarily hides from their view. In this work, we investigate how well users can select targets using Pursuits in cases where the target's trajectory is partially invisible (HiddenPursuits): e.g., can users select a moving target that temporarily hides behind another object? Although HiddenPursuits was not studied in the context of interaction before, understanding how well users can perform HiddenPursuits presents numerous opportunities, particularly for small interfaces where a target's trajectory can cover area outside of the screen. We found that users can still select targets quickly via Pursuits even if their trajectory is up to 50% hidden, and at the expense of longer selection times when the hidden portion is larger. We discuss how gaze-based interfaces can leverage HiddenPursuits for an improved user experience.

A music reader has to “look ahead” from the notes currently being played—this has usually been called the Eye-Hand Span. Given the restrictions on processing time due to tempo and meter, the Early Attraction Hypothesis suggests that sight readers are likely to locally increase the span of looking ahead in the face of complex upcoming symbols (or symbol relationships). We argue that such stimulus-driven effects on looking ahead are best studied using a measure of Eye-Time Span (ETS) which redefines looking ahead as the metrical distance between the position of a fixation in the score and another position that corresponds to the point of metrical time at fixation onset. In two experiments of temporally controlled sight reading, musicians read simple stepwise melodies that were interspersed with larger intervallic skips, supposed to create points of higher melodic complexity (and visual salience) at the notes following the skips. The results support both Early Attraction (lengthening of looking ahead) and Distant Attraction (lengthening of incoming saccades) in the face of relative melodic complexity. Notably, such effects also occurred on the notes preceding the nominally complex ones. The results suggest that saccadic control in music reading depends on temporal restrictions as well as on local variations in stimulus complexity. peerReviewed

Relating mathematical concepts to graphical representations is a challenging task for students. In this paper, we introduce two visual strategies to qualitatively interpret the divergence of graphical vector field representations. One strategy is based on the graphical interpretation of partial derivatives, while the other is based on the flux concept. We test the effectiveness of both strategies in an instruction-based eye-tracking study with N = 41 physics majors. We found that students’ performance improved when both strategies were introduced (74% correct) instead of only one strategy (64% correct), and students performed best when they were free to choose between the two strategies (88% correct). This finding supports the idea of introducing multiple representations of a physical concept to foster student understanding. Relevant eye-tracking measures demonstrate that both strategies imply different visual processing of the vector field plots, therefore reflecting conceptual differences between the strategies. Advanced analysis methods further reveal significant differences in eye movements between the best and worst performing students. For instance, the best students performed predominantly horizontal and vertical saccades, indicating correct interpretation of partial derivatives. They also focused on smaller regions when they balanced positive and negative flux. This mixed-method research leads to new insights into student visual processing of vector field representations, highlights the advantages and limitations of eye-tracking methodologies in this context, and discusses implications for teaching and for future research. The introduction of saccadic direction analysis expands traditional methods, and shows the potential to discover new insights into student understanding and learning difficulties. peerReviewed

Recent research has revealed enhanced autonomic and subjective responses to eye contact only when perceiving another live person. However, these enhanced responses to eye contact are abolished if the viewer believes that the other person is not able to look back at the viewer. We purported to investigate whether this “genuine” eye contact effect can be reproduced with pre‐recorded videos of stimulus persons. Autonomic responses, gaze behavior, and subjective self‐assessments were measured while participants viewed pre‐recorded video persons with direct or averted gaze, imagined that the video person was real, and mentalized that the person could see them or not. Pre‐recorded videos did not evoke similar physiological or subjective eye contact effect as previously observed with live persons, not even when the participants were mentalizing being seen by the person. Gaze tracking results showed, however, increased attention allocation to faces with direct gaze compared to averted gaze directions. The results suggest that elicitation of the physiological arousal in response to genuine eye contact seems to require spontaneous experience of seeing and of being seen by another individual. peerReviewed

Humans have shown a detection advantage of direct vs. averted gaze stimuli in visual search tasks. However, instead of attentional capture by direct gaze, the detection advantage in visual search may depend on attention-grabbing potential of the distractor stimuli to which the target needs to be compared. We investigated attentional capture by direct gaze using the change blindness paradigm, in which successful detection does not require comparison between the target and the distractor items. Participants detected a masked gaze direction change in one of four simultaneously presented schematic faces. The distractor gaze directions were systematically varied across three experiments. Changes resulting in direct gaze were detected more efficiently than those resulting in averted gaze, independently of distractor gaze directions. This finding suggests that the detection advantage is specifically due to attentional capture by direct gaze, not properties of distractor items. peerReviewed

Participants’ eye movements (EMs) and EEG signal were simultaneously recorded to examine foveal and parafoveal processing during sentence reading. All the words in the sentence were manipulated for inter-word spacing (intact spaces vs. spaces replaced by a random letter) and parafoveal preview (identical preview vs. random letter string preview). We observed disruption for unspaced text and invalid preview conditions in both EMs and fixation-related potentials (FRPs). Unspaced and invalid preview conditions received longer reading times than spaced and valid preview conditions. In addition, the FRP data showed that unspaced previews disrupted reading in earlier time windows of analysis, compared to string preview conditions. Moreover, the effect of parafoveal preview was greater for spaced relative to unspaced conditions, in both EMs and FRPs. These findings replicate well-established preview effects, provide novel insight into the neural correlates of reading with and without inter-word spacing and suggest that spatial selection precedes lexical processing. peerReviewed

Laaksonen, Aino-Maija. 2017. Havainnointi ja päätöksenteko naissalibandynpelaajilla. Liikuntatieteellinen tiedekunta, Jyväskylän yliopisto, 77 s. Motorinen taitosuoritus koostuu kolmesta osasta: havainnoinnista, päätöksenteosta ja motorisesta suorituksesta. Tämä vuoksi havainnoinin ja päätöksenteon kehittäminen tulisikin nähdä yhtä tärkeänä kuin itse motorisen taidon harjoittamisen. Tämän tutkimuksen tarkoituksena oli selvittää, kuinka huippupelaajat ja harrastajat eroavat havainnointitaidoissa naissalibandyssä. Tutkimuksessa simuloitiin salibandyssä esiintyviä pelitilanteita siten, että havainnoitavien kohteiden lukumäärä lisääntyi tilanteiden monipuolistuessa. Tutkimukseen osallistui 16 naissalibandynpelaajaa, jotka muodostivat kaksi ryhmää, huippupelaajat ja harrastajat. Tutkimus koostui kolmesta erilaisesta hyökkäystilanteesta. Ensimmäinen tilanne oli läpiajo, toinen 1v1 tilanne ja kolmas 2v1 tilanne. Havainnointia tutkittiin silmänliikkeiden avulla. Silmänliikkeet tallennettiin Tobii Pro 2 Wireless –silmänliikekameralla. Silmänliikkeistä määritettiin fiksaation kesto ja lukumäärä määritettyihin kohteisiin ja siirtymiin kuluva aika fiksaatioiden välissä koko suorituksen ajalta. Analyysissä käytetyt kohteet olivat pallo, maalivahti, maali, kentällä oleva tyhjä tila, syöttösuunta ja puolustajan jalat, vartalo ja maila. Fiksaatioiden kestot ja lukumäärät analysoitiin silmänliikevideosta Dartfish -ohjelmistolla. Huippupelaajien ja harrastajien välisiä eroja tutkittiin toistomittausten varianssianalyysillä (ANOVA). Havainnointitaitoja tutkittaessa havaittiin, että harrastajat katsoivat merkittävästi enemmän palloa jokaisessa tilanteessa (p < 0,001). Läpiajossa huippupelaajat katsoivat harrastajia enemmän maalivahtia (p < 0,001) ja maalia (p = 0,05). 1v1 -tilanteessa huippupelaajat katsoivat enemmän maalivahtia (p = 0,041), puolustajan jalkoja (p = 0,001), maalia (p = 0,011) ja puolustajan vartaloa (p = 0,045). 2v1 -tilanteessa huippupelaajat katsoivat enemmän puolustajan jalkoja (p < 0,001), mailaa (p = 0,012) ja vartaloa (p = 0,009). Lisäksi huippupelaajat katsoivat 2v1 –tilanteessa enemmän maalia (p = 0,039), tyhjiä tiloja (p = 0,004) ja syöttösuuntaa (p = 0,03). Myös fiksaatioiden lukumäärät erosivat ryhmien välillä. Läpiajossa harrastajat katsoivat useammin palloa (p = 0,03). Huippupelaajat katsoivat läpiajossa merkittävästi useammin maalia (p = 0,048) ja maalivahtia (p = 0,001). Myös 1v1 -tilanteessa huippupelaajat katsoivat merkittävästi useammin maalia (p = 0,014) ja maalivahtia (p = 0,05). Lisäksi 1v1 -tilanteessa huippupelaajat katsoivat useammin puolustajan jalkoja (p = 0,027), mailaa (p = 0,032) ja vartaloa (p = 0,017). 2v1 - tilanteessa harrastajat katsoivat useammin palloa (p < 0,001). Huippupelaajat havainnoivat 2v1 -tilanteessa useammin maalia (p = 0,039), puolustajan vartaloa (p = 0,008) ja tyhjiä tiloja (p = 0,003). Tilanteiden muuttuessa fiksaation kesto kohteeseen pallo kasvoi ensin läpiajon ja 1v1 -tilanteen välillä merkittävästi (p = 0,007). Sitä vastoin 1v1 ja 2v1 -tilanteiden välillä pallon katsomisaika puolestaan väheni merkittävästi (p = 0,007). Fiksaation kesto kohteeseen maalivahti vähentyi merkittävästi läpiajon (22 %) ja 1v1 -tilanteen (3,5 %) ja läpiajon ja 2v1 -tilanteen (2 %) välillä (p < 0,001). Myös 1v1 ja 2v1 -tilanteiden välillä oli merkittävä ero (p = 0,044). Kuten tuloksista huomataan, huippupelaajien ja harrastajien ryhmät eroavat havainnoinnin perusteella toisistaan, mutta lisäksi eroja löytyy myös saman ryhmän pelaajien välillä. Tutkimuksen tulosten perusteella voidaan suositella, että salibandyharjoittelun tulisi sisältää harjoitteita, joissa pelaajien on mahdollisuus havainnoida pelin kannalta tärkeitä informaation lähteitä ja oppia tunnistamaan oleellisimmat vihjeet. Laaksonen, Aino-Maija. 2017. Perception and decision making in women’s floorball. Faculty of Sport and Health Sciences, University of Jyväskylä, 77 pp. According to information processing model the motor skill can be divided into three components: perception, decision making and motor execution. Previous studies have shown that the perception and decision making are as important as motor execution itself for the successful motor performance. Therefore, developing one’s (visual) perceptual and decision making skills should be seen as important as practicing one’s motor execution, i.e. technical skills. The aim of this study was to examine the differences in the visual search strategy of the elite and sub-elite players in women’s floorball. In the present study, three game situations common in floorball were simulated so that the number of objects to be followed by the player increased because the number of players in the situation increased. The participants of the study were elite (n=8) and sub-elite players (n=8). The study consisted of three different offensive situations: breakaway, 1v1 and 2v1. The eye movements were recorded by using Tobii Pro 2 Wireless –glasses. From the eye movements, the duration of the fixations, the number of fixations to the areas of special interest and the time when player look for the next object of the fixation, were analyzed. The areas of special interest were ball, goalkeeper, goal, empty spaces, potential passing direction, defender’s feet, body and stick. Duration of the fixation and the number of fixations were analyzed from the eye movement video with Dartfish –software. Differences between the elite and sub-elite players were analyzed with repeated measures ANOVA. In the study, it was found out that the sub-elite players looked significantly more to the ball in every situation (p < 0,001). In breakaway situation, the elite players looked more to the goalkeeper (p < 0,001) and the goal (p = 0, 05). In the 1v1 situation, the elite players looked more to the goalie (p = 0,041), goal (p = 0,011), the defender’s feet (p = 0,001), and the defender’s body (p = 0,045). In the 2v1 situation, the elite players looked more to the defender’s feet (p < 0,001), the stick (p = 0,012) and the body (p = 0,009). In addition, the elite players looked more to the goal (p = 0,039), free spaces (p = 0,004) and potential passing direction (p = 0,03). Significant differences between the groups were also found in the number of fixations. The sub-elite players looked more often to the ball in the breakaway (p = 0, 03). In the breakaway, the elite players looked more often the goal (p = 0,048) and the goalkeeper (p = 0,001). Also in the the 1v1, the elite players looked more often the goal (p = 0,014) and the goalkeeper (p = 0, 05). In addition. The elite players looked more often to defender’s feet (p = 0,027), stick (p = 0,032) and body (p = 0,017) in the 1v1 situation. In the 2v1, the sub-elite players looked more often the ball (p < 0,001). The elite players looked more the goal (p = 0,039), defender’s body (p = 0,008) and free spaces (p = 0,003). Players looked significantly more to the ball in the 1v1 compared to breakaway (p = 0,007). The duration of the fixation to the ball area were smaller in the 2v1 than in the 1v1 (p = 0,007). The duration of the fixation to the goalkeeper decreased as the number of players in the situation increased: breakaway (22 %), 1v1 (3, 5 %) and 2v1 (2 %) (p < 0,001). There was also a significant difference between 1v1 and 2v1 (p = 0,044). These findings suggest that the floorball practice should include situations where players perceptual and decision making skills are stressed. This way the players can learn to recognize essential areas where to pick up the releveant visual information needed for the effective decision making in the floorball.

Tässä pro gradu -tutkielmassa tutkittiin opiskelijan huomion kohdetta lukion fysiikan tunnilla. Tutkimuksessa selvitettiin, vastaako opiskelijan visuaalinen huomio opettajan antamia vihjeitä, kun opettaja opettaa luokassa yhteisesti simulaation avulla. Aineiston kerääminen toteutettiin Tobii Pro Glasses 2 -katseenseurantalaseilla ja SRI-haastattelun avulla ja datan analysointiin käytettiin Microsoft Excel -ohjelmistoa. Luotettavuuden arviointiin käytettiin vertauskoodausta. Tutkimustuloksena oli, että opiskelija seuraa opettajan antamia vihjeitä suurimman osan simulaatio-opetuksen ajasta. Opiskelija katsoi 60 % ajasta sinne, minne opettaja haluaa opiskelijoiden katsovan ja 41 % ajasta opetettavan asian kannalta tärkeimpiä kohtia simulaatiosta. Selkeät kysymykset, esineiden liikuttaminen, työkalujen käyttäminen simulaatiossa, simulaation kuvan kohdistaminen ja osoittaminen kohdistivat opiskelijan huomion. Katse siirtyi pois halutusta kohteesta, kun jollain toisella opiskelijalla oli puheenvuoro tai kun selkeää tehtävää ei ollut. Haastatteluista saatu aineisto tuki analysoinnissa tehtyjä havaintoja. Tulokset osoittavat, että osoittaminen ja kysymysten esittäminen ohjaavat opiskelijan huomiota. Täten opettajakoulutuksessa voisi painottaa osoittamisen ja kysymysten kysymisen merkitystä. Lisäksi oppitunnin sisällön huolellista konstruointia on tärkeä painottaa, jotta opiskelijoilla on mahdollisimman suuren osan ajasta oppituntia selkeitä tehtäviä. Fysiikan opetuksessa voidaan käyttää hyväksi tietokonepohjaisia simulaatioita. Jos simulaatioita halutaan käyttää opetuksessa, niiden käyttöä tulisi harjoitella opettajakoulutuksen aikana. Lisäksi on tärkeää painottaa, miten simulaation käytöstä saadaan paras hyöty irti ja mihin asioihin tulisi kiinnittää huomiota. In this study the student’s gaze location during high school physics lesson was determined. The goal was to find out if the students visual attention corresponds to clues given by teacher when he/she is teaching physics to whole class using simulations. Data was collected with Tobii Pro Glasses 2 -wearable eye tracker and stimulated recall interviews. Data analysis was made with Microsoft Excel. Peer coding was used to test the reliability of coding. The results show that the student followed teacher’s cues most of the time during teaching. Student looked 60 % of time at where the teacher wanted students to look at and 41 % of time the most important things in simulation considering the subject being teached. Explicit questions, moving of objects, use of the tools embedded into the simulation, zooming the simulation view and pointing focused student’s gaze on wanted locations. Gaze moved away from the aimed target when some other student was speaking or when there were no clear tasks for the students. The data from the interviews supports the observations made from the eye-tracking analysis. Results show that pointing and asking questions direct students’ gaze. On the other hand, the careful construction of lesson contents must be emphasized so that students have a clear task most of the time as possible. Computer-based simulations can be used in teaching. If one wants to use them, the use should be rehearsed during teacher training. For addition, it is important to emphasize how one gets the best benefit out of simulations and to where you should pay attention.

Eye tracking is a widely used method for recording eye movements, which are important indicators of ongoing cognitive processes during the viewing of a target stimulus. Despite the variety of applications, the analyses of eye movement data have been lacking of methods that could take both the spatial and temporal information into account. So far, most of the analyses are based on strongly aggregated measures, because eye movement data are considered to be complex due to their richness and large variation between and within the individuals. Therefore, the eye movement methodology needs new statistical tools in order to take full advantage of the data. This dissertation is among the first studies to employ point process statistics for eye movement data in order to understand its spatial nature together with the temporal dynamics. Here, we consider eye movements as a realisation of a spatio-temporal point process. The emphasis is in statistical inference on eye movements using existing point process statistics along with the new methods and models introduced in this work. Our aim is to get understanding of eye movements as a temporally evolving process in space. This objective is achieved in four steps: First, we apply the second-order characteristics of point processes to describe features of the process. Second, we develop new functional summary statistics in order to evaluate the temporal nature of the eye movements. Third, we use likelihood-based modelling to assess the uncertainty related to these data summaries. Fourth, the developed models are used both for group comparisons and for distinguishing components in an eye movement sequence. The empirical results of this dissertation give new information on visual processing of paintings. We find evidence that the viewing process of one subject changes during the inspection of the painting being an indication of learning. The behaviour of this learning effect, however, varies between the individuals. We also study differences between novices and non-novices in art viewing by comparing where they look at and for how long the gaze typically stops. The latter distinguishes the two groups, whereas the former reveals minor differences that are not statistically significant. Altogether, we hope that our results encourage researchers to pay more attention to temporal dynamics in eye movement data, as well as to the inevitable variation in the individual level. The spatio-temporal analysis of eye movements presented here is novel and covers a wide range of methods from functional summary statistics to the likelihood-based modelling. The methods and tools presented are applicable to other eye movement data collected in a freeviewing condition, but we believe that the developed models, being rather simple but flexible, could also be useful for the analysis of spatio-temporal sequences outside the field.

This study used an eye-tracking method to explore students’ approaches to solving the same task in different representations and the differences between students who answered correctly and those who answered incorrectly when solving the problems. Thirty-one upper secondary students took part in the study. According to the results of this study, the representation has a slight effect on students’ problem solving processes. Students with the incorrect answers paid more attention to the parts of the tasks with information irrelevant to determining the solution to the task. peerReviewed

Eye movements are a relatively novel data source for biometric identification. When video cameras applied to eye tracking become smaller and more efficient, this data source could offer interesting opportunities for the development of eye movement biometrics. In this paper, we study primarily biometric identification as seen as a classification task of multiple classes, and secondarily biometric verification considered as binary classification. Our research is based on the saccadic eye movement signal measurements from 109 young subjects. In order to test the data measured, we use a procedure of biometric identification according to the one-versus-one (subject) principle. In a development from our previous research, which also involved biometric verification based on saccadic eye movements, we now apply another eye movement tracker device with a higher sampling frequency of 250 Hz. The results obtained are good, with correct identification rates at 80–90% at their best.

Vastasyntyneen itkun akustiikan on arveltu heijastavan keskus- ja ääreishermoston kehitystasoa. Aiemmissa tutkimuksissa vastasyntyneiden itkun akustisten ominaisuuksien kuten keskimääräisesti korkean perustaajuuden (f0), ja perustaajuuden suuren vaihtelevuuden (SD f0) on havaittu ennustavan heikompaa kognitiivista kehitystä vauvoilla, joilla on merkittäviä lääketieteellisiä riskitekijöitä syntyessään. Ei vielä tiedetä, ennustaako varhainen itku kognitiivista kehitystä myös terveillä täysiaikaisesti syntyneillä vauvoilla. Osana laajempaa tutkimusprojektia, tässä tutkimuksessa tutkittiin yhteyttä vastasyntyneiden itkun perustaajuuden (f0) ominaisuuksien (korkeuden ja vaihtelevuuden) ja myöhemmän tiedonkäsittelyn välillä terveillä täysiaikaisilla vauvoilla. Seurantakäynnillä 8 kuukauden iässä silmänliikkeistä mitattavia reaktioaikoja ja tarkkaavuuden irrottamista eri kasvonilmeistä (neutraali, iloinen, pelokas) ja kontrolliärsykkeestä mitattiin silmänliikekameraa hyödyntäen. Tässä pitkittäistutkimuksessa (n = 44) havaittiin, että itkun perustaajuuden korkeus (f0) oli negatiivisesti yhteydessä tarkkaavuuden irrottamisen todennäköisyyteen 8 kuukauden iässä. Vauvat, joilla oli keskimäärin korkeampi itkun perustaajuus vastasyntyneenä, irrottivat vähemmän todennäköisesti tarkkaavuuttaan huomion kohteena olevasta ärsykkeestä 8 kuukauden iässä. Yhteyden voimakkuus pysyi samana, kun lapsen ikä, syntymäpaino ja pään ympärysmitta syntymähetkellä ja itkun vaihtelevuus oli otettu huomioon. Itkutaajuuden vaihtelevuus (SD f0) ei ollut yhteydessä tarkkaavuuden irrottamistodennäköisyyteen. Tässä pitkittäistutkimuksessa ei havaittu kummankaan vauvan itkun perustaajuusmuuttujan osalta merkitsevää yhteyttä silmänliikkeiden reaktioaikoihin 8 kuukauden iässä (n = 54), eikä molempien itkun taajuusmuuttujien yhteinen selitysosuus usean muuttujan lineaarisessa regressiomallissa ollut merkitsevä reaktioaikojen suhteen, kun lapsen ikä, syntymäpaino ja -pään ympärysmitta oli huomioitu. Yhteenvetona, tässä pitkittäistutkimuksessa havaittiin yhteys vastasyntyneen itkun korkean perustaajuuden ja tarkkaavuuden irrottamistodennäköisyyden välillä 8 kuukauden iässä. Tämä yhteys viittaa siihen, että korkea taajuus on yhteydessä keskushermoston organisaatioon ja ääreishermoston herkkyyteen ja tätä kautta vaikutus heijastuu myös tarkkaavuuden prosesseihin. Jatkossa tästä aiheesta on tärkeää tehdä tarkentavaa tutkimusta vauvoilla, jotka ovat syntyneet ilman, että heillä on merkittäviä lääketieteellisiä riskitekijöitä. Jatkotutkimuksissa, joissa itkun ennustevaikutuksia tarkastellaan tarkkaavuuteen liittyen, tulisi kiinnittää myös huomiota sosioemotionaalisiin riskitekijöihin syntymän ja ensimmäisen elinvuoden aikana, koska näillä tekijöillä on aiemmissa tutkimuksissa havaittu vaikutus ääreishermoston herkkyyteen ja tarkkaavuuden prosesseihin.

Hytönen, Anni ja Mäkelä, Linda. 2016. Kuudesluokkalaiset nettisivua lukemassa: Mitä silmänliikkeet kertovat oppilaiden lukustrategioista? Erityispedagogiikan pro gradu -tutkielma. Jyväskylän yliopisto. Kasvatustieteiden laitos. 47 sivua. Tässä tutkimuksessa selvitettiin kuudesluokkalaisten oppilaiden informaation paikantamisen taitoja nettilukemisen tehtävissä. Tavoitteena oli saada tietoa siitä, millaisia strategioita niin sujuvat kuin hitaat lukijat käyttävät etsiessään tietoa yksittäiseltä nettisivulta. Näitä strategioita tutkittiin silmänliikemenetelmän avulla. Tutkimus on osa Suomen Akatemian rahoittamaa eSeek-hanketta, johon osallistui 426 kuudesluokkalaista. Silmänliiketutkimukseemme valikoitui 59 oppilasta, joista kahdeksalla oli todettu lukemisen pulmia. Tutkimuksessa oppilaiden silmänliikkeitä mitattiin silloin, kun he etsivät nettisivulta vastauksia informaation paikannusta, päättelyä ja muistamista vaativiin kysymyksiin. Tehtävät suoritettiin simuloidussa internetympäristössä ja oppilaiden suoriutumista arvioitiin tehtävissä, jotka mittasivat joko oikean vastauksen löytämistä tekstistä tai tekstissä olleen kuvion tarjoaman lisätiedon muistamista. Suoriutumisen perusteella oppilaat jakautuivat kolmeen suoritusprofiiliryhmään: heikosti tehtävään suuntautuneet lukijat (15 %), tehtäväsuuntautuneet lukijat (49 %) sekä kuvioon ja tehtävään suuntautuneet lukijat (36 %). Heikosti tehtävään suuntautuneet lukijat saivat heikot pisteet kummastakin tehtävästä, kun taas tehtäväsuuntautuneet lukijat saivat hyvät pisteet informaation paikantamisen tehtävästä, mutta pärjäsivät heikommin kuvion muistamistehtävässä. Kuvioon ja tehtävään suuntautuneet lukijat suoriutuivat puolestaan hyvin molemmista tehtävistä. Korrelaatioanalyysin tulokset osoittivat, että lukusujuvuus ja luetunymmärtäminen olivat yhteydessä informaation paikantamisen tehtävässä suoriutumiseen. Lukemisen haasteilla havaittiin olevan yhteys informaation paikantamisen ongelmiin, sillä heikosti tehtävään suuntautuneiden lukijoiden ryhmään kuului 60 % lukipulmaisista oppilaista, kun taas verrokkioppilaista tähän ryhmään kuului vain 8 %. Tutkimuksemme tulosten perusteella voidaan todeta, että osalla oppilaista on heikkouksia lukemisen ja informaation paikantamisen strategioiden hyödyntämisessä nettilukemisessa. Opetuksessa oppilaille tulisikin tarjota erityyppisiä tekstejä, joiden avulla he voisivat harjoitella strategioiden, kuten esimerkiksi rakenteellisten vihjeiden, tavoitteellista käyttöä sekä tukea näiden taitojen harjoitteluun.

We present a computationally light real-time algorithm which automatically detects blinks, saccades, and fixations from electro-oculography (EOG) data and calculates their temporal parameters. The method is probabilistic which allows to consider the uncertainties in the detected events. The method is real-time in the sense that it processes the data sample-by-sample, without a need to process the whole data as a batch. Prior to the actual measurements, a short, unsupervised training period is required. The parameters of the Gaussian likelihoods are learnt using an expectation maximization algorithm. The results show the promise of the method in detecting blinks, saccades, and fixations, with detection rates close to 100 %. The presented method is published as an open source tool.

Urheilussa ja liikuntataitojen oppimisessa havaintokognitiivisilla taidoilla on ratkaiseva merkitys onnistuneen suorituksen kannalta. Moni laji edellyttää tehokasta ennakointitaitoa, jolla säästetään aikaa ja autetaan varsinaista päätöksentekoa vastustajan toiminnan ennakoimisena sekä oman suorituksen helpottamisena. Useassa tutkimuksessa on pystytty osoittamaan videoharjoittelun hyödyllisyys ennakointitaidon kehittymisessä, mutta tätä ei ole riittävästi hyödynnetty valmennuksen tukena. Tämän tutkimuksen tarkoituksena oli selvittää videoharjoittelun vaikutusta koehenkilöiden ennakointitaitojen kehittymiseen tenniksessä. Lisäksi tarkoituksena oli verrata kahden erilaisen ohjaustavan tehokkuutta ennakointitaitojen kehittymisessä. Tutkimukseen osallistui 35 fyysisesti aktiivista liikuntapedagogiikan opiskelijaa. Tutkimus toteutettiin heidän kuusi viikkoa kestävän syventävän palloilun kurssinsa aikana. Koehenkilöt jaettiin neljään ryhmään, joista kolme oli varsinaisia koeryhmiä ja yksi oli kontrolliryhmä, joka osallistui vain alku- ja loppumittauksiin. Koeryhmistä kaksi osallistui tenniskurssin kahden ensimmäisen viikon aikana 4 x 20 minuuttia kestävään ennakointitaitoja kehittävään videoharjoitteluun, jossa annettiin ohjeistusta joko ohjatun oivaltamisen tai suoraohjauksen periaatteilla. Tutkimusaineisto kerättiin ASL silmänliikekameralla ja Dartfish-ohjelmalla. Aineiston tilastollinen analysointi suoritettiin IBM SPSS 19.0 ohjelmalla. Tutkimuksen tuloksissa etenkin videoharjoitteluun osallistuneiden ryhmien reaktioajat paranivat huomattavasti verrattuna muihin ryhmiin ja ero oli myös tilastollisesti merkitsevä. Silmänliikeaineiston analysoinnissa havaittiin videoharjoitteluryhmillä tilastollisesti merkitsevää parannusta fiksaatioiden määrässä alku- ja loppumittauksen välillä. Sen sijaan muiden muuttujien kohdalla ei havaittu tilastollisia merkitsevyyksiä vaikkakin muutokset mittausten välillä olivat merkittäviä niin keskiarvojen parantumisena kuin keskihajontojen pienentymisenä. Tämän tutkimuksen johtopäätöksinä voidaan todeta, että videoharjoittelu vaikutti myönteisesti etenkin reaktioajan parantumiseen. Sitä voidaan pitää tärkeänä tekijänä, koska ajan ”säästö” ennakointitaidossa sekä päätöksenteossa lisää pelaajan mahdollisuutta ehtiä oikeaan paikkaan tekemään lajisuoritustaan. Tenniskurssi yksistään myös paransi reaktioaikaa, mutta erot videoharjoitteluryhmiin jäivät vielä isoiksi. Sen sijaan tällä tutkimuksella ei pystytty osoittamaan, että ohjaustavoilla olisi keskenään ollut vaikutusta reaktioajan tai muiden muuttujien kohdalla. Silmänliikeanalyysin kautta ei saatu eroja ryhmien välille, mutta tulokset rohkaisevat olettamaan, että ennakointitaitoa voidaan kehittää videoharjoittelulla sekä kohdennetulla ohjeistuksella. Tutkimus antoi kuitenkin viitteitä, että suoralla ohjeistuksella pystytään lyhyessä ajassa saavuttamaan parannusta ennakointitaidossa. Sophisticated perceptual-cognitive skills have important role in sport and in learning new skills. Many sports itself demand efficient anticipation that offers usually more time for the decision making, in which the visual perception skills have the largest role. The purpose of this study was to clarify the effect of the video training in developing perceptual-cognitive and anticipation skills in tennis, and furthermore, to compare the effectiveness of two different instruction methods in developing anticipation skills. A total of 35 PE students were recruited from their tennis course to participate in the experiment. All were physically active students with comparable levels of sporting experience. Participants were divided into four groups. Each group of participants completed the pre- and post-tests. Three of the groups took part in the tennis training and one maintained as control group. Two of the training groups also underwent 4 x 20 min of laboratory-based perceptual video training followed with explicit or guided discovery instruction and feedback to develop their anticipation skills. Eye movements were recorded with ASL Eyelink 5000SU system and with Dartfish Team Pro 4.5. The results were analysed using the t-test and a factorial analysis of variance (ANOVA) with the IBM SPSS 19.0 software. Players who received perceptual training improved statistically significantly their performance on laboratory based reaction test compared with control group and other training group. Also the eye movement analyses showed statistically significant results for the video training groups in number of fixations and the mean number of fixation locations between the pre- and post-test. In addition, there were some positive changes in the mean averages and decrease of the standard deviations, but these did not reach the statistical significance. As expected, the video training groups completed their reaction tests faster than other groups. This can be seen as important anticipation factor for the decision making which helps player to be in the right time in the right place for executing the technical response. The tennis training course itself can reduce the reaction time and the additional video training benefits even more. The eye movement analysis didn´t show any significant results between the groups even though they encourage the use of video training and targeted instruction for developing anticipation skills. Research cannot show statistically significant results between the two instruction models but explicit model can offer better results in anticipation for the short term period.

Eye movement data are outputs of an analyser tracking the gaze when a person is inspecting a scene. These kind of data are of increasing importance in scientific research as well as in applications, e.g. in marketing and man-machine interface planning. Thus the new areas of application call for advanced analysis tools. Our research objective is to suggest statistical modelling of eye movement sequences using sequential spatial point processes, which decomposes the variation in data into structural components having interpretation. We consider three elements of an eye movement sequence: heterogeneity of the target space, contextuality between subsequent movements, and time-dependent behaviour describing self-interaction. We propose two model constructions. One is based on the history-dependent rejection of transitions in a random walk and the other makes use of a history-adapted kernel function penalized by user-defined geometric model characteristics. Both models are inhomogeneous self-interacting random walks. Statistical inference based on the likelihood is suggested, some experiments are carried out, and the models are used for determining the uncertainty of important data summaries for eye movement data., Comment: 27 pages, 13 figures and 2 tables

Previous research on the effect of word length on reading confounded the number of letters (NrL) in a word with its spatial width. Consequently, the extent to which visuospatial and attentional-linguistic processes contribute to the word length effect on parafoveal and foveal vision in reading and dyslexia is unknown. Scholars recently suggested that visual crowding is an important factor for determining an individual’s reading speed in fluent and dyslexic reading. We studied whether the NrL or the spatial width of target words affects fixation duration and saccadic measures in natural reading in fluent and dysfluent readers of a transparent orthography. Participants read natural sentences presented in a proportional font that contained spatially narrow and wide four- to seven-letter target words. The participants looked at spatially narrow words overall for a longer duration partially due to more frequent regressions, which showed that crowding can disrupt word recognition during normal reading. In addition, reliable NrL effects on fixation duration suggest that letters are important attentional units during reading. Saccadic measures including relative landing position, refixation and skipping probability were strongly affected by spatial width and slightly affected by the NrL, which suggests that saccadic programming and parafoveal processing of upcoming words are limited by visual acuity more than by attentional factors. The dysfluent readers overall had longer fixation durations for words but did not show larger crowding or NrL effects. peerReviewed

Tietokoneen käyttäjän varmentaminen silmänliikkeiden perusteella Tutkimus käsittää tietokoneen käyttäjän biometrisen verifioinnin kehittämistä perustuen käyttäjän nopeisiin silmänliikkeisiin, sakkadeihin. Tällöin käyttäjästä tehdyillä silmänliikemittauksilla todennetaan, onko kyseinen henkilö oikea (autentikoitu) käyttäjä vai ei. Biometrista verifiointia eli käyttäjän vahvistamista on aiemmin tutkittu varsinkin sormenjälkikuvista, joista on kaupallisia sovelluksia, mutta myös mm. kasvo-, silmänpohja- ja kämmenkuvista. Nämä kaikki ovat biometrisiä datalähteitä. Tässä tutkimuksessa biometrisenä datana olivat henkilön silmänliikkeet. Tähän mennessä näitä ovat tutkineet biometristä verifiointia varten vain muutama muu tutkija maailmassa. Silmänliiketutkimuksia on luonnollisesti lääketieteessä ja psykologiassa tehty jo vuosikymmeniä ja tietokoneiden käyttöliittymienkin yhteydessä parikymmentä vuotta. Verrattuna muihin biometrisiin datoihin silmänliikkeiden hyvät puolet verifioinnin mielessä voivat olla seuraavat: vaikeampi imitoida ja datan yksinkertaisuuden vuoksi helpompi prosessointi, mikä tuottaa nopean laskennan. Väitöstutkimuksen tekijä on tutkinut ja kuvaa tutkimuksessaan laskennallisia menetelmiä, joilla saadaan laskettua silmänliikkeistä henkilöiden välillä vaihtelevia ominaisuuksia verifiointia varten. Tekijä mittasi silmänliikevideokamerasysteemillä koehenkilöiden silmänliikkeet näiden katsellessa tarkoitukseen sopivia stimulaatioita (ärsykkeitä), kuten kuvaruudulla liikkuvia pieniä kohteita. Vertailudatana oli jo aiemmissa tutkimuksissa elektro-okulograafisesti mitattuja eli silmän etu- takaosan väliseen jännite-eroon perustuvia signaaleja, jolloin oli käytetty samanlaisia stimulaatioita kuin silmänliikekameroilla. Tekijä käytti signaalianalyysia silmänliikkeiden tunnistamiseksi signaalidatasta. Väitöstutkimuksen tekijä kehitti testausproseduurit, tietokoneohjelmat, kuinka tehdä mittaukset ja erottaa kulloinenkin oikea käyttäjä muista koehenkilöistä, jotka esittivät testeissä laittomia tunkeilijoita. Hän perusti tämän verifioinnin useisiin tiedonlouhinnan ja koneoppimisen luokitusmenetelmiin, kuten suoraviivainen lähimmän naapurin etsintäalgoritmi ja edellistä kehittyneempi, mutta monimutkaisempi algoritmi nimeltä tukivektorikone. Tekijä testasi kehittämillään laskentamenetelmillä, kuinka usein oli mahdollista verifioida oikein asianomainen, oikea käyttäjä (oikeiden positiivisten määrät) ja kuinka usein pystyttiin erottamaan väärät yrittäjät (oikeiden negatiivisten määrät). Parhaimmillaan testit ylsivät erinomaiseen tulokseen, noin 95 prosenttia. Lisäksi hän toisti testejä samoille koehenkilöille päivien ja viikkojenkin väliajoilla voidakseen tutkia, miten koehenkilöiden silmänliikkeiden ominaisuuksien mahdollinen ajasta riippuva vaihtelevuus vaikuttaisi biometrisen verifiointiin. Vaihtelevuus vaikutti vain suhteellisen vähän laskien luokitustarkkuutta noin 90 prosenttiin. Tätä saattoi kuitenkin vähän vielä parantaa käyttämällä toista silmänliikevideokamerasysteemiä, jonka näytteenottotaajuus on 250 Hz. Aluksi tekijä käytti systeemiä, jossa se oli ainoastaan 30 Hz. Tätä matalaa taajuutta oli kuitenkin mielekästä kokeilla, sillä se vastaa halpojen, tietokoneissa olevien kamerasysteemien (eivät vielä silmänliikekameroita) ominaisuuksia. Kun voidaan olettaa tulevaisuudessa tietokoneiden ja älypuhelimien käyttöliittymään liitetyn silmänliikekameran käyttäjän katseen eli silmänliikkeiden tunnistamiseksi, tähän voitaisiin kytkeä myös biometrinen verifiointi. On jo olemassa älypuhelimia, joissa käyttöliittymä hyödyntää käyttäjän katseensuuntaa tunnistaen käyttäjän kuvaruudulla kulloinkin katsoman paikan. Väitöstutkimus osoitti, että tietokoneen käyttäjä on mahdollista verifioida luotettavasti henkilöstä mitattujen silmänliikkeiden perusteella. This thesis focuses on biometric verification of subjects based on saccadic eye movements. Verification corresponds to two-class classification to recognize an authenticated user and to classify other subjects as impostors. Compared with other biometric signals or data, the possible advantages of eye movements can be as follows: harder to imitate, easier processing and faster computation. The thesis describes a procedure to use variables of saccade eye movements recorded. It analyses the variabilities between electro-oculography (EOG) and video-oculography (VOG) signals: i.e. eye movements were recorded with skin electrodes or with two special video cameras. When a signal was recorded with a low-frequency video camera device simulating a web camera, the sampling frequency of signals was enhanced using interpolation. The techniques of signal processing and statistics were also applied to analysis. In order to evaluate biometric accuracy, the test procedures for true positive rate (TPR) and true negative rate (TNR) were designed separately. Many classification methods were explored for verification performance, including both modified simple methods such as k-nearest neighbour searching and advanced methods such as neural networks and support vector machines. Approaches and other details in the verification procedure were improved through multiple tests and comparisons of the verification accuracies. Optimal parameters and settings of the classification methods used were found. With more and more saccades and subjects collected into training sets, a high TNR accuracy was gained, which was close to 95% at its best. It showed that, using saccade eye movements, it was possible to distinguish between an authenticated user and impostors. On the other hand, after multiple recordings of subjects, the high accuracy of TPR – close to 90% – also confirmed that an authenticated user can be recognized notwithstanding the variability of variable values of saccades between different sessions. Finally, better results given by signals with a relatively high sampling frequency of 250 Hz were obtained, and this could allow user verification based on eye movements to be applied in practice, along with the development of eye movement video cameras in future.

The role of different orthographic units (letters, syllables, words) in reading of orthographically transparent Finnish language was studied by independently manipulating the number of letters (NoL) and syllables (NoS) in words and pseudowords and by recording eye movements during repeated reading aloud of these items. Fluent adult readers showed evidence for using larger orthographic units in (pseudo)word recoding, whereas dysfluent children seem to be stuck in a letter-based decoding strategy, as lexicality and item repetition decreased the NoL effect only among adult readers. The NoS manipulation produced weak repetition effects in both groups. However, dysfluent children showed evidence for word-specific knowledge by making fewer fixations on words than pseudowords; moreover, repetition effects were more noticeable for words than pseudowords, as indexed by shortened average fixation durations on words due to item repetition. The number of fixations was generally reduced by repetition among dysfluent children, suggesting familiarity-based benefits perhaps at the perceptual level of processing. peerReviewed

In previous eye movement research on word length effects, spatial width has been confounded with the number of letters. McDonald (2006) unconfounded these factors by rendering all words in sentences in constant spatial width. In the present study, the Arial font with proportional letter spacing was used for varying the number of letters while equating for spatial width, while the Courier font with monospaced letter spacing was used to measure the contribution of spatial width to the observed word length effect. Number of letters in words affected single fixation duration on target words, whereas words’ spatial width determined fixation locations in words and the probability of skipping a word. The results support the existence of distinct subsystems for deciding where and when to move eyes in text (Rayner & McConkie, 1976). The number-of-letters effect in fixation duration may be explained by visual acuity, visual crowding, and/or serial letter processing. peerReviewed