Synaesthesia is a fascinating condition in which ordinary stimuli elicit extraordinary sensory experiences. For example, specific tastes may elicit unusual tactile sensations and standard black letters may elicit highly specific colour experiences. These unusual experiences have been shown to have substantial impact on cognition, emotion, perception, and covert attention. Two experiments are presented which show that synaesthesia also influences overt visual attention. In these experiments two grapheme-colour synaesthetes viewed coloured letters while their eye movements were tracked. Letters were presented in colours that were either congruent or incongruent with the synaesthetes' colours. Eye tracking analysis showed that synaesthetes exhibited a colour congruity bias – a propensity to fixate congruently coloured letters more often and for longer durations than incongruently coloured letters – in a naturalistic free viewing task. In a more structured visual search task, this congruity bias caused synaesthetes to rapidly fixate and identify congruently coloured target letters, but led to problems in identifying incongruently coloured target letters. The results are discussed in terms of their implications for perception in synaesthesia.

Synaesthesia is a fascinating condition in which ordinary stimuli elicit extraordinary sensory experiences. For example, specific tastes may elicit unusual tactile sensations and standard black letters may elicit highly specific colour experiences. These unusual experiences have been shown to have substantial impact on cognition, emotion, perception, and covert attention. Two experiments are presented which show that synaesthesia also influences overt visual attention. In these experiments two grapheme-colour synaesthetes viewed coloured letters while their eye movements were tracked. Letters were presented in colours that were either congruent or incongruent with the synaesthetes' colours. Eye tracking analysis showed that synaesthetes exhibited a colour congruity bias – a propensity to fixate congruently coloured letters more often and for longer durations than incongruently coloured letters – in a naturalistic free viewing task. In a more structured visual search task, this congruity bias caused synaesthetes to rapidly fixate and identify congruently coloured target letters, but led to problems in identifying incongruently coloured target letters. The results are discussed in terms of their implications for perception in synaesthesia.

In seminal work, Yarbus examined the characteristic scanpaths that result when viewing an image, observing that scanpaths varied significantly depending on the question posed to the observer. While early efforts examining this hypothesis were equivocal, it has since been established that aspects of an observer’s assigned task may be inferred from their gaze. In this thesis we examine two datasets that have not previously been considered involving prediction of task and observer sentiment respectively. The first of these involves predicting general tasks assigned to observers viewing images, and the other predicting subjective ratings recorded after viewing advertisements. The results present interesting observations on task groupings and affective dimensions of images, and the value of various measurements (gaze or image based) in making these predictions. Analysis also demonstrates the importance of how data is partitioned for predictive analysis, and the complementary nature of gaze specific and image derived features. / May 2016

This thesis explores the relationship between fixation location and the locus of attention during reading. Early theories of eye movement control during reading suggested that a very tight coupling exists between the two (Just & Carpenter, 1980); however, it has since been shown that dissociations do exist. Whether these dissociations necessarily implicate parallel lexical processing, or whether they can be accommodated for within a serial-sequential framework is explored in a series of experiments. Experiment 1 tested whether parallel lexical processing is, at the very least, psychologically plausible. Two horizontally aligned letter strings were presented simultaneously on a screen, the task being to decide whether they were physically identical or not. Even when presentation duration should have been short enough to prohibit the strictly serial processing of each word in turn, the results show clear lexical effects: high frequency words were responded to faster and with fewer errors than low frequency words. Effects of lexicality and orthography were also found. These results suggest that the two words had been processed at a lexical level in an overlapping fashion. Experiments 2 and 3 investigated the nature and range of word n+2 preview effects. In Experiment 2, word n+1 was either a determiner or 3-letter alternative higher frequency word; in Experiment 3, word n+1 was either a 4- or a 6-letter high frequency word. A gaze contingent display change technique was employed, where prior to passing an invisible boundary located immediately after word n, one, the other, neither or both of words n+1 and n+2 received a nonword preview. In addition to showing orthographic parafoveal-on-foveal effects stemming from word n+1, there was also evidence that word n+2 preview influenced targeting decisions on words n and n+1. Word n+2 preview effects are also found on word n+2 and in the spillover region. These effects were most wide ranging when word n+1 length was an average of 5- compared to 3-letters. Higher-level plausibility preview effects were explored in Experiments 4-6, again using a gaze contingent display change technique. In Experiment 4 word n+1 received either an identical preview, a different but plausible one, or an anomalous, or nonword preview. Critically, an effect of plausibility arose on word n+1, with anomalous previews receiving longer inspection times than alternative plausible previews. Experiments 5 and 6 investigated the range over which these effects might occur, testing for a plausibility preview effect on word n+2. Results showed numerical, but not statistical evidence for a plausibility-related preview effect on word n+2. There were, however, clear orthographic word n+2 preview effects. Finally, Experiment 7 experimentally tested the immediate oculomotor response to a mislocated fixation, using a text shift paradigm to simulate saccadic error and measuring the effect on lexical processing. Critically, this experiment showed that a quick error correction strategy appears to be engaged following a simulated saccadic undershoot, rather than a stay and process response. This suggests that a mislocated fixation account coupled with a stay and process response is unlikely to provide a viable explanation for lexical parafoveal-on-foveal effects. Overall, it is suggested that current instantiations of both serial (e.g., Reichle, Warren & McConnell, 2009) and parallel (e.g., Schad & Engbert, 2012) models of eye movement control during reading appear to fail to capture major aspects of these patterns of results. The results do, however, appear to fit most parsimoniously with a perspective on eye movement control that allows for multiple words to be processed in an overlapping fashion.

Alfalfa, Medicago sativa L., cultivars, breeding lines and germplasm releases (populations) and Rhizobium meliloti L. strains that exhibit nitrogen fixation efficiency and tolerance to salinity and drought stresses should enhance seedling establishment, increase yields, reduce nitrogen dependency on petroleum-based nitrogen fertilizers, and allow wider use of irrigated lands in semiarid and a rid regions. In vitro experiments were conducted to determine relative salt (sodium chloride -- NaCl) tolerance: l) during germination and early seedling growth of 229 alfalfa populations from North Africa, the Middle East and the United States, 2) survival and growth of 92 rhizobial strains obtained from different laboratories in the United States or isolated from host plants growing in saline and arid regions of the Intermountain west, 3) compatibility, nodulation and nitrogen fixation efficiency of the most salt-tolerant alfalfa populations and rhizobial strains, and 4) survival, nodulation and nitrogen fixation efficiency of the most salt-tolerant alfalfa populations and rhizobial strain tested under drought conditions. Results from screening of alfalfa at salinity levels of 0 to 3.2 S m-1 (0.1 S m-1 = 640 mg L-1 = 10 mM NaCl at 25° C) indicated 29 populations exhibited salt tolerance at 2.8 S m-1. At salinity levels of 0 to 7.2 S m-1, 14 rhizobial strains exhibited salt tolerance at 6.4 s m-1. Compatibility, nodulation and nitrogen fixation efficiency in the 29 alfalfa populations and the 14 rhizobial strains under controlled conditions showed that four of the rhizobial strains were highly compatible with all 29 populations. These 29 populations and four strains were then exposed to 0 to 1.6 S m-1 NaCl, with the result that nitrogen was fixed with highly compatible symbionts at 1.6 S m-1 NaCl. From these results, the six most highly compatible alfalfa populations and the best overall rhizobial strain were combined and tested under simulated drought stress. These populations were able to fix more nitrogen under drought stress (-0.76 MPa) (0.088 nmol seedling-1 s-1) than they did under salt stress (1.6 S m-1) (0.066 nmol seedling-1 s-1). The in vitro screening technique for acetylene reduction appears to be a useful tool for detecting physiological changes due to salinity and water stresses and for measuring seedling nitrogen fixation efficiency. Breeding for drought and salinity tolerance in conjunction with high nitrogen fix ing potential may be more realistic than breeding strictly for nitrogen fixation without regard for environmental adaptation.

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Think-aloud interviews are a strategy used to identify misconceptions held by students. We incorporated think-aloud interviews and studied representational competence of novice and expert participants with identifying alkyl halides with multiple representations. We hypothesized that the participants would approach representations differently and think-aloud interviews would reveal misconceptions. Eye-tracking results showed that novice and expert participants differ in their approaches to representations and that novice participants spend more time on representations. Think-aloud interviews revealed that novice participants contain misconceptions on alkyl halide identification. This research provided insights on student understanding in identifying alkyl halides and representations, allowing instructors to use student misconceptions in guiding student learning. A second think-aloud interview study was incorporated in studying the representational competence of novice and expert participants of alkyl halide substitution and elimination reactions. We hypothesized that the approach to solving reactions would differ and that think- aloud interviews would reveal misconceptions. Eye-tracking results showed that there was a difference in participant patterns. Think-aloud interviews revealed that novice participants contain misconceptions and lacked content knowledge when approaching reactions. This research provided insights on student understanding of substitution and elimination reactions and identified areas of content knowledge concern. Alternative learning approaches work to improve understanding by presenting material differently. Alternative approaches to quiz question types were designed to promote student understanding of organic chemistry and encourage alternative approaches to solving organic questions. This research study determines whether alternative quiz question could support students to be more successful in organic chemistry. Laboratory experiments allow students to acquire hands-on experience in with instruments and laboratory techniques. We designed a new undergraduate laboratory experiment written to demonstrate how Iron-based tandem catalysis is connected to pharmaceutical production. This laboratory experiment was designed to improve student interest in laboratory learning and enhance student product identification by thin layer chromatography and 1H NMR.

La dyslexie développementale est un trouble neuro-développemental qui affecte spécifiquement l’apprentissage du langage écrit d’environ 10% des enfants en âge scolaire. Ces dernières années, plusieurs études ont montré la présence des anomalies oculomotrices chez les enfants dyslexiques. Toutefois, plusieurs questions sur la performance oculomotrice des enfants dyslexiques sont encore sans réponse ou restent peu étudiées.Dans cette thèse, nous avons réalisé trois études afin d’examiner l’oculomotricité des enfants dyslexiques comparativement à celle des enfants non-dyslexiques. Pour la première fois, nous avons enregistré les saccades verticales chez les enfants dyslexiques (étude 1). Les résultats ont montré que, comparés aux enfants non-dyslexiques de même âge chronologique, les enfants dyslexiques avaient des latences plus longues, de faibles précisions et des vitesses saccadiques ayant une asymétrie haut/bas. Les études 2 et 3 nous ont permis d’élargir les investigations, respectivement, sur la fixation visuelle et sur la reconnaissance visuo-auditive phonologique chez les enfants dyslexiques. Nous avons reporté une fixation visuelle et une reconnaissance visuo-auditive phonologique de faible qualité chez les enfants dyslexiques par rapport aux groupes d’enfants-non dyslexiques de même âge chronologique et de même âge de lecture.Nous avons suggéré que le développement atypique du système visuel magnocellulaire, de même que celui des structures cortico-sous-corticales et des difficultés attentionnelles expliqueraient les perturbations oculomotrices des enfants dyslexiques. Ainsi, nous avons proposé des voies de rééducation oculomotrice en vue de contribuer à l’amélioration des capacités de lecture des enfants dyslexiques.Mots-clés: Mouvements oculaires, saccades, fixations, système visuel, cortex visuel, structures cortico-sous-corticales, attention, dyslexie développementale. / ABSTRACTDevelopmental dyslexia is a neurodevelopmental disorder that affects written language learning of about 10% of school-age children. During the last years, several studies have shown the presence of oculomotor abnormalities in dyslexia. However, several questions about the oculomotor performance of dyslexic children are still unanswered.We conducted three studies to examine eye movements of dyslexic children with respect to non-dyslexic age-matched children. In the first of our study, we investigated vertical saccades performance in dyslexic children. The results showed that, dyslexic children had longer latencies, poor precision and slow saccadic speed with up / down asymmetry. Studies 2 and 3 respectively allowed us to enlarge the investigation of visual fixation as well as visual-auditory phonological capabilities in dyslexic children. We reported a low quality of visual fixation and visual-auditory phonological recognition in children with dyslexia compared with the non-dyslexic children.Taken together, all these findings suggested, in dyslexic children, an immaturity of the magnocellular visual system, as well as of the cortico-subcortical structures responsible for oculomotor performances. Attentional capabilities, that are poor in dyslexic children, would be also explained their oculomotor deficiencies reported. Thus, we proposed oculomotor rehabilitation that could be able to improve reading skills in dyslexia.Key words: Eye movements, saccades, fixations, visual system, visual cortex, cortical and sub-cortical structures, attention, developmental dyslexia.

O conceito de controle de estímulos é composto por dois processos correlatos, a discriminação operante e a generalização de estímulos. A relação entre a discriminação e a emissão da resposta de observação tem sido amplamente realizada. A relação entre a generalização e a emissão da resposta de observação, por outro lado, ainda carece de investigação empírica. O principal objetivo deste trabalho foi investigar a duração de fixações aos estímulos em testes de generalização compostos por variações nas dimensões de S+ e por variações nas dimensões de S-. Dez estudantes universitários foram expostos a um procedimento de discriminação sucessiva caracterizado por um esquema múltiplo VI / EXT. Três estímulos Gabor eram apresentados em formação triangular sobre um fundo preto. O estímulo com inclinação das linhas da grade de 45 cumpriu a função de S+, o de inclinação 135 função de S- e os estímulos com linhas horizontais e verticais eram irrelevantes em relação à tarefa. A Fase 1 do treino discriminativo caracterizou-se por um esquema Mult VI 1 seg \\ EXT durante o qual os estímulos discriminativos eram apresentados de forma semi randômica no vértice superior do triangulo. Durante a fase 2, o esquema foi alterado para Mult VI 2 seg \\ EXT e os estímulos alternavam de posição a cada componente. Em seguida ao treino discriminativo cinco participantes foram expostos a um teste de generalização, em extinção, compostos por estímulos de angulações de 15, 30, 45, 60 e 75, enquanto cinco participantes foram expostos a um teste de generalização composto por estímulos de angulações de 105, 120, 135 e 150. Os resultados do teste de generalização composto por variações de S+ demonstram a formação de gradientes de observação em forma de sino. Os resultados do teste de generalização, por outro lado, demonstram a formação de gradientes de observação achatados, em forma de sino e em forma de U. Estes resultados complementam o cenário de compreensão do processo de estabelecimento de controle de estímulos ao demonstrar a formação de gradientes de observação, além disto, indicam que testes de generalização podem ser utilizados como alternativa metodológica à investigação das funções dos estímulos discriminativos sobre a resposta de observação / Stimulus control is a concept based on two related processes, operant discrimination and stimulus generalization. The relation between operant discrimination and observing responses has been widely investigated, while the relation between stimulus generalization and observing responses still lacks empirical research. The aim of this project was to assess the duration of eye fixations during generalization tests on stimulus that were variations of S+ and variations of S-. Ten college students participated of a simple successive discrimination procedure with a Mult VI/EXT schedule. Three Gabor stimuli were arranged in a triangular shape over a black background. The S+ stimulus was the one with lines on a 45° slope and the S- was the one with lines on a 135° slope. Stimuli with vertical (90°) and horizontal (180°) lines were presented as part of the arrangement but were irrelevant to the task. In Phase 1, discriminative training was conducted using a Mult VI 1 s/EXT schedule with S+ and S- alternating in a semi-random sequence on the upper corner of the triangular arrangement. During Phase 2, the schedule changed to Mult VI 2 s/EXT and the position of the S+ and S- varied over the three corners of the triangle in each component. After completing the discriminative training, five participants were exposed to a generalization test, in extinction, with variations from S+, where stimuli of 15°, 30°, 45°, 60°, and 75° were presented. The remaining five participants were exposed to the generation test with stimuli varying from S-, with stimuli of 105°, 120°, 135°, and 150°. Results from the generalization test with variations from S+ show bell-shaped gradients of observing response with peak near S+ and lessened at slopes more distant from S+. On the other hand, gradients from the test conducted with variations from S- were variable, producing flat gradients, bell-shaped, and u-shaped gradients. These results add to the comprehension of stimulus control process by showing gradients of observing behavior and suggest that generalization tests could be used as an alternative to study the role of discriminative stimulus for the observing response

O conceito de controle de estímulos é composto por dois processos correlatos, a discriminação operante e a generalização de estímulos. A relação entre a discriminação e a emissão da resposta de observação tem sido amplamente realizada. A relação entre a generalização e a emissão da resposta de observação, por outro lado, ainda carece de investigação empírica. O principal objetivo deste trabalho foi investigar a duração de fixações aos estímulos em testes de generalização compostos por variações nas dimensões de S+ e por variações nas dimensões de S-. Dez estudantes universitários foram expostos a um procedimento de discriminação sucessiva caracterizado por um esquema múltiplo VI / EXT. Três estímulos Gabor eram apresentados em formação triangular sobre um fundo preto. O estímulo com inclinação das linhas da grade de 45 cumpriu a função de S+, o de inclinação 135 função de S- e os estímulos com linhas horizontais e verticais eram irrelevantes em relação à tarefa. A Fase 1 do treino discriminativo caracterizou-se por um esquema Mult VI 1 seg \\ EXT durante o qual os estímulos discriminativos eram apresentados de forma semi randômica no vértice superior do triangulo. Durante a fase 2, o esquema foi alterado para Mult VI 2 seg \\ EXT e os estímulos alternavam de posição a cada componente. Em seguida ao treino discriminativo cinco participantes foram expostos a um teste de generalização, em extinção, compostos por estímulos de angulações de 15, 30, 45, 60 e 75, enquanto cinco participantes foram expostos a um teste de generalização composto por estímulos de angulações de 105, 120, 135 e 150. Os resultados do teste de generalização composto por variações de S+ demonstram a formação de gradientes de observação em forma de sino. Os resultados do teste de generalização, por outro lado, demonstram a formação de gradientes de observação achatados, em forma de sino e em forma de U. Estes resultados complementam o cenário de compreensão do processo de estabelecimento de controle de estímulos ao demonstrar a formação de gradientes de observação, além disto, indicam que testes de generalização podem ser utilizados como alternativa metodológica à investigação das funções dos estímulos discriminativos sobre a resposta de observação / Stimulus control is a concept based on two related processes, operant discrimination and stimulus generalization. The relation between operant discrimination and observing responses has been widely investigated, while the relation between stimulus generalization and observing responses still lacks empirical research. The aim of this project was to assess the duration of eye fixations during generalization tests on stimulus that were variations of S+ and variations of S-. Ten college students participated of a simple successive discrimination procedure with a Mult VI/EXT schedule. Three Gabor stimuli were arranged in a triangular shape over a black background. The S+ stimulus was the one with lines on a 45° slope and the S- was the one with lines on a 135° slope. Stimuli with vertical (90°) and horizontal (180°) lines were presented as part of the arrangement but were irrelevant to the task. In Phase 1, discriminative training was conducted using a Mult VI 1 s/EXT schedule with S+ and S- alternating in a semi-random sequence on the upper corner of the triangular arrangement. During Phase 2, the schedule changed to Mult VI 2 s/EXT and the position of the S+ and S- varied over the three corners of the triangle in each component. After completing the discriminative training, five participants were exposed to a generalization test, in extinction, with variations from S+, where stimuli of 15°, 30°, 45°, 60°, and 75° were presented. The remaining five participants were exposed to the generation test with stimuli varying from S-, with stimuli of 105°, 120°, 135°, and 150°. Results from the generalization test with variations from S+ show bell-shaped gradients of observing response with peak near S+ and lessened at slopes more distant from S+. On the other hand, gradients from the test conducted with variations from S- were variable, producing flat gradients, bell-shaped, and u-shaped gradients. These results add to the comprehension of stimulus control process by showing gradients of observing behavior and suggest that generalization tests could be used as an alternative to study the role of discriminative stimulus for the observing response