967 resultados para selective attention


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Steady-state visual evoked potentials (SSVEPs) were recorded from the scalp of human subjects who were cued to attend to a rapid sequence of alphanumeric characters presented to one visual half-field while ignoring a concurrent sequence of characters in the opposite half-field. These two-character sequences were each superimposed upon a small square background that was flickered at a rate of 8.6 Hz in one half-field and 12 Hz in the other half-field. The amplitude of the frequency-coded SSVEP elicited by either of the task-irrelevant flickering backgrounds was significantly enlarged when attention was focused upon the character sequence at the same location. This amplitude enhancement with attention was most prominent over occipital-temporal scalp areas of the right cerebral hemisphere regardless of the visual field of stimulation. These findings indicate that the SSVEP reflects an enhancement of neural responses to all stimuli that fall within the "spotlight" of spatial attention, whether or not the stimuli are task-relevant. Recordings of the SSVEP provide a new approach for studying the neural mechanisms and functional properties of selective attention to multi-element visual displays.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Attention for threatening information was investigated using a computerised version of the emotional Stroop. The study examined the influence of state and trait anxiety in an unselected student sample assigned to high trait anxious (HTA) or low trait anxious (LTA) groups on the basis questionnaire scores. State anxiety was manipulated within participants through the threat of electric shock. Threatening words that were either unrelated (e.g., cancer, danger) or related to the source of the threat (e.g., electrocute, shock) were presented to participants both within and outside of awareness. In the latter condition, a backward masking procedure was used to prevent awareness of the stimulus material. In the masked condition, despite chance performance in identification of the lexical status of stimulus items, HTA participants showed facilitated colour naming for all threat words relative to control items under threat of shock, but this effect was not evident in the shock safe condition. For unmasked trials the HTA group showed significant interference in colour naming for all threat words relative to controls under the threat of shock, but not in the shock safe condition. Neither valence of the items nor the threat of shock influenced colour naming latencies for the LTA group. [ABSTRACT FROM AUTHOR]

Relevância:

100.00% 100.00%

Publicador:

Resumo:

According to some models of visual selective attention, objects in a scene activate corresponding neural representations, which compete for perceptual awareness and motor behavior. During a visual search for a target object, top-down control exerted by working memory representations of the target's defining properties resolves competition in favor of the target. These models, however, ignore the existence of associative links among object representations. Here we show that such associations can strongly influence deployment of attention in humans. In the context of visual search, objects associated with the target were both recalled more often and recognized more accurately than unrelated distractors. Notably, both target and associated objects competitively weakened recognition of unrelated distractors and slowed responses to a luminance probe. Moreover, in a speeded search protocol, associated objects rendered search both slower and less accurate. Finally, the first saccades after onset of the stimulus array were more often directed toward associated than control items.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

One of the overarching questions in the field of infant perceptual and cognitive development concerns how selective attention is organized during early development to facilitate learning. The following study examined how infants' selective attention to properties of social events (i.e., prosody of speech and facial identity) changes in real time as a function of intersensory redundancy (redundant audiovisual, nonredundant unimodal visual) and exploratory time. Intersensory redundancy refers to the spatially coordinated and temporally synchronous occurrence of information across multiple senses. Real time macro- and micro-structural change in infants' scanning patterns of dynamic faces was also examined. ^ According to the Intersensory Redundancy Hypothesis, information presented redundantly and in temporal synchrony across two or more senses recruits infants' selective attention and facilitates perceptual learning of highly salient amodal properties (properties that can be perceived across several sensory modalities such as the prosody of speech) at the expense of less salient modality specific properties. Conversely, information presented to only one sense facilitates infants' learning of modality specific properties (properties that are specific to a particular sensory modality such as facial features) at the expense of amodal properties (Bahrick & Lickliter, 2000, 2002). ^ Infants' selective attention and discrimination of prosody of speech and facial configuration was assessed in a modified visual paired comparison paradigm. In redundant audiovisual stimulation, it was predicted infants would show discrimination of prosody of speech in the early phases of exploration and facial configuration in the later phases of exploration. Conversely, in nonredundant unimodal visual stimulation, it was predicted infants would show discrimination of facial identity in the early phases of exploration and prosody of speech in the later phases of exploration. Results provided support for the first prediction and indicated that following redundant audiovisual exposure, infants showed discrimination of prosody of speech earlier in processing time than discrimination of facial identity. Data from the nonredundant unimodal visual condition provided partial support for the second prediction and indicated that infants showed discrimination of facial identity, but not prosody of speech. The dissertation study contributes to the understanding of the nature of infants' selective attention and processing of social events across exploratory time.^

Relevância:

70.00% 70.00%

Publicador:

Resumo:

It has been proposed that body image disturbance is a form of cognitive bias wherein schemas for self-relevant information guide the selective processing of appearancerelated information in the environment. This threatening information receives disproportionately more attention and memory, as measured by an Emotional Stroop and incidental recall task. The aim of this thesis was to expand the literature on cognitive processing biases in non-clinical males and females by incorporating a number of significant methodological refinements. To achieve this aim, three phases of research were conducted. The initial two phases of research provided preliminary data to inform the development of the main study. Phase One was a qualitative exploration of body image concerns amongst males and females recruited through the general community and from a university. Seventeen participants (eight male; nine female) provided information on their body image and what factors they saw as positively and negatively impacting on their self evaluations. The importance of self esteem, mood, health and fitness, and recognition of the social ideal were identified as key themes. These themes were incorporated as psycho-social measures and Stroop word stimuli in subsequent phases of the research. Phase Two involved the selection and testing of stimuli to be used in the Emotional Stroop task. Six experimental categories of words were developed that reflected a broad range of health and body image concerns for males and females. These categories were high and low calorie food words, positive and negative appearance words, negative emotion words, and physical activity words. Phase Three addressed the central aim of the project by examining cognitive biases for body image information in empirically defined sub-groups. A National sample of males (N = 55) and females (N = 144), recruited from the general community and universities, completed an Emotional Stroop task, incidental memory test, and a collection of psycho-social questionnaires. Sub-groups of body image disturbance were sought using a cluster analysis, which identified three sub-groups in males (Normal, Dissatisfied, and Athletic) and four sub-groups in females (Normal, Health Conscious, Dissatisfied, and Symptomatic). No differences were noted between the groups in selective attention, although time taken to colour name the words was associated with some of the psycho-social variables. Memory biases found across the whole sample for negative emotion, low calorie food, and negative appearance words were interpreted as reflecting the current focus on health and stigma against being unattractive. Collectively these results have expanded our understanding of processing biases in the general community by demonstrating that the processing biases are found within non-clinical samples and that not all processing biases are associated with negative functionality

Relevância:

70.00% 70.00%

Publicador:

Resumo:

A set of five tasks was designed to examine dynamic aspects of visual attention: selective attention to color, selective attention to pattern, dividing and switching attention between color and pattern, and selective attention to pattern with changing target. These varieties of visual attention were examined using the same set of stimuli under different instruction sets; thus differences between tasks cannot be attributed to differences in the perceptual features of the stimuli. ERP data are presented for each of these tasks. A within-task analysis of different stimulus types varying in similarity to the attended target feature revealed that an early frontal selection positivity (FSP) was evident in selective attention tasks, regardless of whether color was the attended feature. The scalp distribution of a later posterior selection negativity (SN) was affected by whether the attended feature was color or pattern. The SN was largely unaffected by dividing attention across color and pattern. A large widespread positivity was evident in most conditions, consisting of at least three subcomponents which were differentially affected by the attention conditions. These findings are discussed in relation to prior research and the time course of visual attention processes in the brain.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

The goal of this study is to identify cues for the cognitive process of attention in ancient Greek art, aiming to find confirmation of its possible use by ancient Greek audiences and artists. Evidence of cues that trigger attention’s psychological dispositions was searched through content analysis of image reproductions of ancient Greek sculpture and fine vase painting from the archaic to the Hellenistic period - ca. 7th -1st cent. BC. Through this analysis, it was possible to observe the presence of cues that trigger orientation to the work of art (i.e. amplification, contrast, emotional salience, simplification, symmetry), of a cue that triggers a disseminate attention to the parts of the work (i.e. distribution of elements) and of cues that activate selective attention to specific elements in the work of art (i.e. contrast of elements, salient color, central positioning of elements, composition regarding the flow of elements and significant objects). Results support the universality of those dispositions, probably connected with basic competencies that are hard-wired in the nervous system and in the cognitive processes.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Campaigns raise public interest in politics and allow parties to convey their messages to voters. However, voters' exposure and attention during campaigns are biased towards parties and candidates they like. This hinders parties' ability to reach new voters. This paper theorises and empirically tests a simple way in which parties can break partisan selective attention: owning an issue. When parties own issues that are important for a voter, that voter is more likely to notice them. Using survey data collected prior to the 2009 Belgian regional elections it is shown that this effect exists independent of partisan preferences and while controlling for the absolute visibility of a party in the media. This indicates that issue ownership has an independent impact on voters' attention to campaigns. This finding shows that owning salient issues yields (potential) advantages for parties, since getting noticed is a prerequisite for conveying electoral messages and increasing electoral success.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Les dysfonctions attentionnelles suivant un traumatisme craniocérébral (TCC) compliquent souvent la reprise des activités de la vie quotidienne et influencent négativement le pronostic de réinsertion socio-académique et professionnelle. Or, les cliniciens de réadaptation disposent d’un nombre limité d’outils de remédiation cognitive dont l’efficacité est démontrée et qui sont adaptés à une population francophone. Cette étude vise à démontrer l’efficacité d’un protocole d’entrainement intensif des fonctions attentionnelles : « Attention! Prêt? On s’enTraine! » (Séguin, Lahaie & Beauchamp, 2012), basé sur une adaptation française de l’« Attention Process Training-I » (APT-I; Sohlberg & Mateer, 1987). Dix-sept participants ayant subi un TCC et présentant des déficits attentionnels ont reçu 15 séances d’entrainement attentionnel avec le programme « Attention! Prêt? On s’enTraine! » (n = 8) ou de l’aide aux devoirs (n = 9). Suite à l’intervention, les participants du groupe expérimental ont amélioré leur rendement dans plusieurs fonctions ciblées par l’intervention attentionnelle, notamment au niveau du balayage visuel, de l’attention sélective et de l’alternance attentionnelle. De plus, les gains se sont généralisés à des fonctions connexes, puisqu’une meilleure performance a été retrouvée dans des tâches de mémoire de travail, d’inhibition, de flexibilité cognitive et de planification visuoconstructive. La démonstration de l’effet positif d’un entrainement intensif sur le rendement attentionnel pourrait inciter les cliniciens et chercheurs à développer et à valider d’autres protocoles de remédiation cognitive francophones, pour les fonctions attentionnelles ou d’autres sphères de la cognition. Par le fait même, le pronostic fonctionnel de la clientèle pédiatrique en traumatologie en sera potentialisé.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Voluntary selective attention can prioritize different features in a visual scene. The frontal eye-fields (FEF) are one potential source of such feature-specific top-down signals, but causal evidence for influences on visual cortex (as was shown for "spatial" attention) has remained elusive. Here, we show that transcranial magnetic stimulation (TMS) applied to right FEF increased the blood oxygen level-dependent (BOLD) signals in visual areas processing "target feature" but not in "distracter feature"-processing regions. TMS-induced BOLD signals increase in motion-responsive visual cortex (MT+) when motion was attended in a display with moving dots superimposed on face stimuli, but in face-responsive fusiform area (FFA) when faces were attended to. These TMS effects on BOLD signal in both regions were negatively related to performance (on the motion task), supporting the behavioral relevance of this pathway. Our findings provide new causal evidence for the human FEF in the control of nonspatial "feature"-based attention, mediated by dynamic influences on feature-specific visual cortex that vary with the currently attended property.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

According to the broaden-and-build theory of positive emotions, positive emotions broaden while negative emotions narrow thought-action repertoires. These processes reflect changes in attentional scope, which is the focus of this research. The present study tested the hypothesis that participants in negative mood would be better able to focus on a target figure and separate it from its context in a perceptual task, and would also be better able to focus on the task amid a distracting environment than participants in a positive mood. An undergraduate sample of 77 participants watched video clips selected to induce either fear or amusement, and completed an Embedded Figures Test either in a quiet setting or in a noisy setting. A higher-order ANOVA revealed that Mood had a marginally significant effect on task performance, F(1, 73) = 3.94, p = .051, and that Distraction, F(1, 72) = 4.61, p = .035 and the Mood x Distraction interaction, F(1, 73) = 9.12, p = .003 did significantly affect task performance. However, contrary to the hypothesis, the effect of the distraction manipulation was greater for participants in a negative mood than it was for participants in a positive mood. The author suggests future directions to clarify the relationship between emotions, attentional scope, and susceptibility to environmental distraction.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

In the current study we investigated whether ego depletion negatively affects attention regulation under pressure in sports by assessing participants' dart throwing performance and accompanying gaze behavior. According to the strength model of self-control, the most important aspect of self-control is attention regulation. Because higher levels of state anxiety are associated with impaired attention regulation, we chose a mixed design with ego depletion (yes vs. no) as between-subjects and anxiety level (high vs. low) as within-subjects factor. Participants performed a perceptual-motor task requiring selective attention, namely, dart throwing. In line with our expectations, depleted participants in the high-anxiety condition performed worse and displayed a shorter final fixation on bull's eye, demonstrating that when one's self-control strength is depleted, attention regulation under pressure cannot be maintained. This is the first study that directly supports the general assumption that ego depletion is a major factor in influencing attention regulation under pressure.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

In the present study we investigated whether ego depletion negatively affects attention regulation under pressure in sports by assessing participants’ dart throwing performance and accompanying gaze behavior. According to the strength model of self-control the most important aspect of self-control is attention regulation (Schmeichel & Baumeister, 2010). As higher levels of state anxiety are associated with impaired attention regulation (Nieuwenhuys & Oudejans, 2012) we chose a mixed design with ego depletion (yes vs. no) as between-subjects and anxiety level (high vs. low) as within-subjects factor. A total of 28 right-handed students participated in our study (Mage = 23.4, SDage = 2.5; 10 female; no professional dart experience). Participants performed a perceptual-motor task requiring selective attention, namely, dart throwing. The task was performed while participants were positioned high and low on a climbing wall (i.e., with high and low levels of anxiety). In line with our expectations, a mixed-design ANOVA revealed that depleted participants in the high anxiety condition performed worse (p < .001) and displayed a shorter final fixation on bull’s eye (p < .01) than in the low anxiety condition, demonstrating that when one is depleted attention regulation under pressure cannot be maintained. This is the first study that directly supports the general assumption that ego depletion is a major factor in influencing attention regulation under pressure.