Journal of Eye Tracking, Visual Cognition and Emotion nº 01 (2011)

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http://hdl.handle.net/10437/11305

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Percorrer Journal of Eye Tracking, Visual Cognition and Emotion nº 01 (2011) por assunto "EYE TRACKING"

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    Attention to health cues on product packages
    (Edições Universitárias Lusófonas, 2011) Orquin, Jacob; Scholderer, Joachim; EPCV - School of Psychology and Life Sciences
    The objectives of the study were (a) to examine which information and design elements on dairy product packages operate as cues in consumer evaluations of product healthfulness, and (b) to measure the degree to which consumers voluntarily attend to these elements during product choice. Visual attention was measured by means of eye-tracking. Task (free viewing, product healthfulness evaluation, and purchase likelihood evaluation) and product (five different yoghurt products) were varied in a mixed within-between subjects design. The free viewing condition served as a baseline against which increases or decreases in attention during product healthfulness evaluation and purchase likelihood evaluation were assessed. The analysis revealed that the only element operating as a health cue during product healthfulness evaluation was the nutrition label. The information cues used during purchase likelihood evaluation were the name of the product category and the nutrition label. Taken together, the results suggest that the only information element that consumers consistently utilize as a health cue is the nutrition label and that only a limited amount of attention is devoted to read nutrition labels during purchase likelihood evaluations. The study also revealed that the probability that a consumer will read the nutrition label during the purchase decision process is associated with gender, body mass index and health motivation.
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    Attentional orienting to biologically fear-relevant stimuli: data from eye tracking using the continual alternation flicker paradigm
    (Edições Universitárias Lusófonas, 2011) Rosa, Pedro Joel; Gamito, Pedro; Oliveira, Jorge; Morais, Diogo; Saraiva, Tomaz; EPCV - School of Psychology and Life Sciences
    Snakes are thought as fear-relevant stimuli (biologically prepared to be associated with fear) which can lead to an enhanced attentional capture when compared fear-irrelevant stimuli. Inherent limitations related to the key-press behaviour might be bypassed with the measurement of eye movements, since they are more closely related to attentional processes than reaction times. An eye tracking technique was combined with the flicker paradigm in two studies. A sample of university students was gathered. In both studies, an instruction to detect changes between the pair of scenes was given. Attentional orienting for the changing element in the scene was analyzed, as well the role of fear of snakes as a moderator variable. The results for both studies revealed a significant shorter time to first fixation for snake stimuli when compared to control stimuli. A facilitating effect of fear of snakes was also found for snakes, presenting the highly fear participants a shorter a time to first fixation for snake stimuli when compared to low-feared participants. The results are in line with current research that supports the advantage of snakes to grab attention due their evo-biological significance.
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    Low cost eye tracking for human-machine interfacing
    (Edições Universitárias Lusófonas, 2011) Lemahieu, Wounter; Wyns, Bart; EPCV - School of Psychology and Life Sciences
    One of the main challenges for developers of new human-computer interfaces is to provide a more natural way of interacting with computer systems, avoiding excessive use of hand and finger movements. In this way, also a valuable alternative communication pathway is provided to people suffering from motor disabilities. This paper describes the construction of a low cost eye tracker using a fixed head setup. Therefore a webcam, laptop and an infrared lighting source were used together with a simple frame to fix the head of the user. Furthermore, detailed information on the various image processing techniques used for filtering the centre of the pupil and different methods to calculate the point of gaze are discussed. An overall accuracy of 1.5 degrees was obtained while keeping the hardware cost of the device below 100 euros.
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    Using eye-tracking to detect reading difficulties
    (Edições Universitárias Lusófonas, 2011) Luegi, Paula; Costa, Armanda; Faria, Isabel Hub; EPCV - School of Psychology and Life Sciences
    Taking into account the study of Luegi (2006), where eye movements of 20 Portuguese university students while reading text passages were analyzed, in this article we discuss some methodological issues concerning eye tracking measures to evaluate reading difficulties. Relating syntactic complexity, grammaticality and ambiguity to eye movements, we will discuss the use of many different dependent variables that indicate the immediate and delayed processes in text processing. We propose a new measure that we called Progression-Path which permits analyzing, in the critical region, what happens when the reader proceeds on the sentence instead of going backwards to solve a problem that s/he found (which is the most common expected behavior but not the only one, as is illustrated by some of our examples).
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    Using eye-tracking to study anaphoric relations processing in European Portuguese
    (Edições Universitárias Lusófonas, 2011) Costa, Armanda; Matos, Gabriela; Luegi, Paula; EPCV - School of Psychology and Life Sciences
    In this study we evaluate processing costs of different types of anaphoric expressions during reading. We consider three types of anaphoric expressions in Subject sentential position: a null pronoun (pro), and two gaps produced by syntactic movement: a WHvariable and a NP copy. Given that coreferential pro exhibits more referential weight than wh- and NP-gaps, and grounded on theories of referential processing based on relations of hierarchy and accessibility of the antecedent, we raise the hypothesis that the more dependent on its antecedent the anaphoric null constituent is, and the more minimal is the distance in terms of hierarchical structure between the anaphoric null element and its antecedent, the lower are the cognitive costs in processing. To test our hypothesis, we registered the eye movements with R6-HS ASL system of 20 Portuguese adult native speakers. Text regions including the selected anaphoric expressions were delimited and tagged. We analyzed the reading time of each region taking into account the number and duration of eye fixations per region; we used the reading time by character in milliseconds in order to compare values between regions of different length. We found a significant advantage in the reading time of the gaps arising from movement over the reading time of pro.