5 resultados para Tracker

em ReCiL - Repositório Científico Lusófona - Grupo Lusófona, Portugal


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Sabe-se que a velocidade de processamento de informação visual é afetada pela ingestão de álcool, já que os consumidores excessivos têm uma menor velocidade de processamento de informação visual do que os não consumidores. O objetivo deste estudo foi o de verificar se o consumo de álcool afete a velocidade de processamento de informação visual de imagens criativas e neutras. Para estudar esta questão os participantes (consumidores de álcool e não consumidores) observaram cenários compostos por dois tipos de imagens (criativas e neutras). A amostra foi composta por 113 estudantes universitários, dos quais 97 eram consumidores de álcool e 16 eram abstinentes. Imagens criativas e não criativas foram então apresentadas num paradigma de competição. Os movimentos dos olhos foram registados continuamente com o Eye-tracker Tobii T60. Os tempos de reação, tal como o tempo total de fixação durante a apresentação de imagens foram analisados. Os resultados mostraram efeitos significativos (p> 0,05) do consumo de álcool na velocidade de processamento de informação visual. No entanto as imagens criativas foram processadas mais rapidamente do que as imagens neutras (p <0,05), com efeito de interação no sexo. Encontraram-se também diferenças significativas (p <0,05) entre as imagens criativas e as imagens neutras no tempo total de fixação.

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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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Federmeier and Benjamin (2005) have suggested that semantic encoding for verbal information in the right hemisphere can be more effective when memory demands are higher. However, other studies (Kanske & Kotz, 2007) also suggest that visual word recognition differ in function of emotional valence. In this context, the present study was designed to evaluate the effects of retention level upon recognition memory processes for negative and neutral words. Sample consisted of 15 right-handed undergraduate portuguese students with normal or corrected to normal vision. Portuguese concrete negative and neutral words were selected in accordance to known linguistic capabilities of the right hemisphere. The participants were submitted to a visual half-field word presentation using a continuous recognition memory paradigm. Eye movements were continuously monitored with a Tobii T60 eye-tracker that showed no significant differences in fixations to negative and neutral words. Reaction times in word recognition suggest an overall advantage of negative words in comparison to the neutral words. Further analysis showed faster responses for negative words than for neutral words when were recognised at longer retention intervals for left-hemisphere encoding. Electrophysiological data through event related potentials revealed larger P2 amplitude over centro-posterior electrode sites for words studied in the left hemifield suggesting a priming effect for right-hemisphere encoding. Overall data suggest different hemispheric memory strategies for the semantic encoding of negative and neutral words.

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The increasing use of the World Wide Web has promised a huge advertising platform for marketers. Investment in online advertising is growing and is expected to overcome traditional media. However, recent studies have reported that users avoid looking at advertising displayed on the World Wide Web. This study aimed at examining the impact of verbal emotional cues (negative/neutral/positive) to capture attention on website’s advertising areas through an eye tracker system. The results revealed significant statistical differences between fixations to negative, positive words and neutral words. Significant differences between the number of fixations and recognition of the target words were found only for the negative valence words. We conclude that negative emotional words could play a major role on user attention to advertising.

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The effect of multiple sclerosis (MS) on the ability to identify emotional expressions in faces was investigated, and possible associations with patients’ characteristics were explored. 56 non-demented MS patients and 56 healthy subjects (HS) with similar demographic characteristics performed an emotion recognition task (ERT), the Benton Facial Recognition Test (BFRT), and answered the Hospital Anxiety and Depression Scale (HADS). Additionally, MS patients underwent a neurological examination and a comprehensive neuropsychological evaluation. The ERT consisted of 42 pictures of faces (depicting anger, disgust, fear, happiness, sadness, surprise and neutral expressions) from the NimStim set. An iViewX high-speed eye tracker was used to record eye movements during ERT. The fixation times were calculated for two regions of interest (i.e., eyes and rest of the face). No significant differences were found between MS and HC on ERT’s behavioral and oculomotor measures. Bivariate and multiple regression analyses revealed significant associations between ERT’s behavioral performance and demographic, clinical, psychopathological, and cognitive measures.