Biomedical subjects

Dominique Lamy

Publications and source records attributed to Dominique Lamy.

13 recordsLinked to original sources

PubMed2007

Threat-related attentional bias in anxious and nonanxious individuals: a meta-analytic study.

This meta-analysis of 172 studies (N = 2,263 anxious,N = 1,768 nonanxious) examined the boundary conditions of threat-related attentional biases in anxiety. Overall, the results show that the bias is reliably demonstrated with different experimental paradigms and under a variety of experimental conditions, but that it is only an effect size of d = 0.45. Although processes requiring conscious perception of threat contribute to the bias, a significant bias is also observed with stimuli outside awareness. The bias is of comparable magnitude across different types of anxious populations (individuals with different clinical disorders, high-anxious nonclinical individuals, anxious children and adults) and is not observed in nonanxious individuals. Empirical and clinical implications as well as future directions for research are discussed.

Anxiety↗

PubMed2006

Reduced auditory processing capacity during vocalization in children with Selective Mutism.

BACKGROUND: Because abnormal Auditory Efferent Activity (AEA) is associated with auditory distortions during vocalization, we tested whether auditory processing is impaired during vocalization in children with Selective Mutism (SM). METHODS: Participants were children with SM and abnormal AEA, children with SM and normal AEA, and normally speaking controls, who had to detect aurally presented target words embedded within word lists under two conditions: silence (single task), and while vocalizing (dual task). To ascertain specificity of auditory-vocal deficit, effects of concurrent vocalizing were also examined during a visual task. RESULTS: Children with SM and abnormal AEA showed impaired auditory processing during vocalization relative to children with SM and normal AEA, and relative to control children. This impairment is specific to the auditory modality and does not reflect difficulties in dual task per se. CONCLUSIONS: The data extends previous findings suggesting that deficient auditory processing is involved in speech selectivity in SM.

Auditory Perception↗

PubMed2006

Attention to eyes and mouth in high-functioning children with autism.

In the present study, we used a probe-detection task to compare attentional allocation to the eyes versus mouth regions of the face in high-functioning boys with autism relative to normal control boys matched for chronological age and IQs. We found that with upright faces, children from both groups attended more to the eyes region than to the mouth region, and to the same extent. This pattern of behavior was observed for not only initial orientation of attention, but also when enough time was provided for attention to be disengaged from its initial locus. The present findings suggest that atypical face processing in autism does not result from abnormal attentional allocation to the different face parts.

Attention↗

PubMed2006

Nature and nurture in own-race face processing.

A standard visual preference task was used to examine 3-month-olds' looking times at own-race versus other-race faces as a function of environmental exposure to faces from the two categories. Participants were Caucasian infants living in a Caucasian environment, African infants living in an African environment, and African infants living in a predominantly Caucasian environment. The results indicate that preference for own-race faces is present as early as 3 months of age, but that this preference results from exposure to the prototypical facial environment.

Cognition↗

PubMed2006

Effects of search mode and intertrial priming on singleton search.

There is no consensus as to what information guides search for a singleton target. Does the most salient display element capture attention, regardless of the observer's attentional set? Do observers adopt a default salience-based search mode? Does knowledge of the target's defining featural property (when available) affect search? Finally, can intertrial contingencies account for the disparate results in the literature? We investigated search for a shape singleton when (1) the target and nontarget shapes switched unpredictably from trial to trial, (2) the target feature remained fixed, and (3) the target was a singleton on only one third of the trials. We examined overall reaction times, search slopes, errors, and the magnitude of the slowing caused by a cross-dimensional singleton distractor. Our results argue against the idea that search is guided solely by stimulus-driven factors or that subjects adopt a singleton detection mode that is blind to feature information. They show also that intertrial contingencies, although potent, cannot account for the variety of results in the literature.

Attention↗

PubMed2006

Grouping does not require attention.

Many theories of visual perception stipulate that Gestalt grouping occurs preattentively. Subjects' failure to report perceiving even salient grouping patterns under conditions of inattention challenges this assumption (see, e.g., Mack, Tang, Tuma, Kahn, & Rock, 1992), but Moore and Egeth (1997) showed that although subjects are indeed unable to identify grouping patterns outside the focus of attention, effects of these patterns on visual perception can be observed when they are assessed using implicit, rather than explicit, measures. However, this finding, which is the only one to date demonstrating grouping effects without attention, is open to an alternative account. In the present study, we eliminated this confound and replicated Moore and Egeth's findings, using the Müller-Lyer illusion (Experiments 1 and 2). Moreover, we found converging evidence for these findings with a variant of the flanker task (Experiment 3), when the amount of available attentional resources was varied (Experiments 4 and 5). The results reinforce the idea that, although grouping outside the focus of attention cannot be the object of overt report, grouping processes can occur without attention.

Attention↗

PubMed2006

Effects of top-down guidance and singleton priming on visual search.

Recent literature suggests that observers can use advance knowledge of the target feature to guide their search but fail to do so whenever the target is reliably a singleton. Instead, they engage in singleton-detection mode--that is, they search for the most salient object. In the present study, we aimed to test the notion of a default salience-based search mode. Using several measures, we compared search for a known target when it is always a singleton (fixed-singleton search) relative to when it is incidentally a singleton (multiple-target search). We examined the relative contributions of strategic factors (knowledge that the target is a singleton) and intertrial repetition effects (singleton priming, or the advantage of responding to a singleton target if the target on the previous trial had also been a singleton). In two experiments, singleton priming eliminated all the differences in performance between fixed-singleton and multiple-target search, suggesting that search for a known singleton may be feature based rather than salience based.

Exploratory Behavior↗

PubMed2005

Attentional bias in anxiety: a behavioral and ERP study.

Accumulating evidence suggests the existence of a processing bias in favor of threat-related stimulation in anxious individuals. Using behavioral and ERP measures, the present study investigated the deployment of attention to face stimuli with different emotion expressions in high-anxious and low-anxious participants. An attention-shifting paradigm was used in which faces with neutral, angry, fearful, sad, or happy expressions were presented singly at fixation. Participants had to fixate on the face cue and then discriminate a target shape that appeared randomly above, below, to the left, or right of the fixated face. The behavioral data show that high-anxious participants were slower to respond to targets regardless of the emotion expressed by the face cue. In contrast, the ERP data indicate that threat-related faces elicited faster latencies and greater amplitudes of early ERP components in high-anxious than in low-anxious individuals. The between-group pattern in ERP waveforms suggests that the slower reaction times in high-anxious participants might reflect increased attentional dwelling on the face cues, rather than a general slowing of response enacting.

Adolescent↗

PubMed2005

Temporal expectations modulate attentional capture.

Subjects' ability to override attentional capture by salient distractors during singleton search has been attributed to the adoption of an attentional set for the type of discontinuity characterizing the target (Folk, Remington, & Johnston, 1992) or to fast disengagement of attention from the salient distractor's location (Theeuwes, Atchley, & Kramer, 2000). The present results support an alternative account by showing that temporal expectancies modulate attentional capture. In a color singleton search, an irrelevant onset preceding the target by a given time interval produced capture when the distractor-to-target interval varied unpredictably but failed to do so when this interval was predictable. Moreover, with unpredictable intervals and moderately salient stimuli, capture was overridden at the expected average interval. These findings invite caution when stimulus onset asynchrony manipulations are used to study the temporal deployment of attention, since they demonstrate that such manipulations introduce powerful temporal expectations.

Attention↗

PubMed2004

Effects of task relevance and stimulus-driven salience in feature-search mode.

Attentional allocation in feature-search mode (W. F. Bacon & H. E. Egeth, 1994) is thought to be solely determined by top-down factors, with no role for stimulus-driven salience. The authors reassessed this conclusion using variants of the spatial cuing and rapid serial visual presentation paradigms developed by C. L. Folk and colleagues (C. L. Folk, R. W. Remington, & J. C. Johnston, 1992; C. L. Folk, A. B. Leber, & H. E. Egeth, 2002). They found that (a) a nonsingleton distractor that possesses the target feature produces attentional capture, (b) such capture is modulated by bottom-up salience, and (c) resistance to capture by irrelevant singletons is mediated by inhibitory processes. These results extend the role of top-down factors in search for a nonsingleton target while arguing against the notion that effects of bottom-up salience and top-down factors on attentional priority are strictly encapsulated within distinct search modes.

Attention↗

PubMed2003

Attentional capture in singleton-detection and feature-search modes.

Six experiments were conducted to determine the circumstances under which an irrelevant singleton captures attention. Subjects searched for a target while ignoring a salient distractor that appeared at different stimulus onset asynchronies (SOAs) prior to each search display. Spatial congruency and interference effects were measured. The strategies available to find the target were controlled (only singleton-detection mode, only feature-search mode, or both search strategies available). An irrelevant abrupt onset captured attention in search for a color target, across SOAs, whatever strategies were available. In contrast, in search for a shape target, an irrelevant color singleton captured attention in the singleton-detection condition but delayed response at its location in the feature-search condition, across SOAs. When both strategies were available, capture was short lived (50- to 100-msec SOAs). The theoretical implications of these findings in relation to current views on attentional capture are discussed. ((c) 2003 APA, all rights reserved)

Adult↗

PubMed2003

Does a salient distractor capture attention early in processing?

Kim and Cave (1999) used spatial probes in order to measure the effects of bottom-up and top-down factors on the allocation of spatial attention over time. Subjects searched for a target with a unique shape, with a uniquely colored distractor present on each trial. The singleton distractor captured attention early in processing, whereas attention homed in on the target's location later on. Kim and Cave (1999) concluded that top-down factors cannot prevent the presence of a salient distractor from delaying target selection. The present study tested the idea that such results were obtained only because subjects adopted the strategy of searching for the most salient item. Kim and Cave's (1999) finding was replicated in Experiment 1. In Experiment 2, instead of a feature search, subjects performed a conjunction search-that is, a task that could not be performed using a salience-based strategy. Probe response times were longest at the salient distractor's location at both the short and the long stimulus onset asynchronies. These results suggest that, early in processing, top-down factors can exert their influence and prevent the capture of attention by a salient distractor.

Attention↗

PubMed2002

Object-based selection: the role of attentional shifts.

The objective of this paper was to investigate under what conditions object-based effects are observed. Recently, Watson and Kramer (1999) used a divided-attention task and showed that unless top-down factors induce a bias toward selection at a higher level, object-based effects are obtained when same-object targets belong to the same uniformly connected (single-UC) region, but not when they belong to different single-UC regions grouped into a higher order object (grouped-UC regions). We refine this claim by proposing that a critical factor in determining whether or not object-based effects with grouped-UC regions are observed is the need to shift attention. The results of four experiments support this hypothesis. Stimuli and displays were similar to those used by Egly, Driver, and Rafal (1994). Subjects had to make size judgments. Using different paradigms, we obtained object-based effects when the task required shifts of attention (spatial cuing, same vs. different judgment with asynchronous target onsets), but not when attention remained either broadly distributed (same vs. different judgment with simultaneous targets) or tightly focused (response competition paradigm).

Attention↗