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Biomedical subjects

Serge Brédart

Publications and source records attributed to Serge Brédart.

11 recordsLinked to original sources
PubMed2006

Brain response to one's own name in vegetative state, minimally conscious state, and locked-in syndrome.

BACKGROUND: A major challenge in the management of severely brain-injured patients with altered states of consciousness is to estimate their residual perception of the environment. OBJECTIVE: To investigate the integrity of detection of one's own name in patients in a behaviorally well-documented vegetative state (VS), patients in a minimally conscious state (MCS), and patients with locked-in syndrome. DESIGN: We recorded the auditory evoked potentials to the patient's own name and to 7 other equiprobable first names in 15 brain-damaged patients. RESULTS: A P3 component was observed in response to the patient's name in all patients with locked-in syndrome, in all MCS patients, and in 3 of 5 patients in a VS. P3 latency was significantly (P<.05) delayed for MCS and VS patients compared with healthy volunteers. CONCLUSIONS: These results suggest that partially preserved semantic processing could be observed in noncommunicative brain-damaged patients, notably for the detection of salient stimuli, such as the subject's own name. This function seems delayed in MCS and (if present) in VS patients. More important, a P3 response does not necessarily reflect conscious perception and cannot be used to differentiate VS from MCS patients.

Acoustic Stimulation↗
PubMed2006

The accuracy of memory for faces of personally known individuals.

The present study was aimed at evaluating whether the very high accuracy of memory for familiar faces, demonstrated by Ge et al (2003, Perception 32 601-614) with a very familiar famous person, generalises to faces of personally known individuals. The accuracy of participants' perceptual memory for a close colleague's face and for their own face was evaluated by presenting original and manipulated pictures of these two targets. The manipulation consisted of increasing or decreasing the interocular distance. As in Ge et al's study, results indicated that proportions of correct recognition of the original faces, and just noticeable differences for the detection of alterations in the recognition task, were not significantly different from the corresponding measures in a perceptual discrimination task performed by a sample of participants who did not know the target persons at all. High accuracy of memory generalises to faces of personally known individuals.

Adolescent↗
PubMed2006

Short article one's own face is hard to ignore.

One's own face possesses two properties that make it prone to grab attention: It is a face, and, in addition, it is a self-referential stimulus. The question of whether the self-face is actually an especially attention-grabbing stimulus was addressed by using a face-name interference paradigm. We investigated whether interference from a flanking self-face on the processing of a target classmate's name was stronger than interference from a classmate's flanking face on the processing of one's own name as the target. In a control condition a third familiar face served as the flanker for both decisions from the participant's own name and from the classmate's name. The presentation of the self-face as a flanker produced significantly more interference on the identification of a classmate's name than the presentation of that classmate's face did on the identification of one's own name. This result was due to the interfering power of the self-face and not to a particular resistance of one's name to interfering facial stimuli. We argue that the emotional value or the high familiarity of one's own face may explain its attention-grabbing property.

Adolescent↗
PubMed2005

Naming very familiar people: when retrieving names is faster than retrieving semantic biographical information.

One of the most reliable findings in the literature on person indentification is that semantic categorization of a face occurs more quickly than naming a face. Here we present two experiments in which participants are shown the faces of their colleagues, i.e., personally familiar people, encountered with high frequency. In each experiment, naming was faster than making a semantic classification, despite the fact that the semantic classifications were highly salient to the participants (Experiment 1: highest degree obtained; Experiment 2: nationality). The finding is consistent with models that allow or parallel access from faces to semantic information and to names, and demonstrates the need for the frequency of exposure to names to be taken into account in models of proper name processing e.g. Burke, Mackay, Worthley and Wade (1991).

Adult↗
PubMed2004

When memory shifts toward more typical category exemplars: accentuation effects in the recollection of ethnically ambiguous faces.

In 4 studies, the authors examined the impact of categorization on the recollection of ethnically ambiguous faces. Participants were presented with faces lying at various locations on mixed-race continua (i.e., Caucasian-North African and Caucasian-Asian faces were used as source images in a morphing program). In all studies, the prevalence of exclusive ethnic features in a face distorted participants' recollections of the face toward faces more typical of the category. Specifically, the recollection of 30% North African (or 30% Asian) faces shifted toward Caucasian source faces, whereas the recollection of 70% North African (or 70% Asian) faces shifted toward North African (Asian) source faces. Memory distortions did not emerge for extremely ambiguous (50%) faces and proved larger on mixed-race than same-race continua (Studies 3 and 4). Memory distortions also emerged with high levels of confidence. The authors elaborate on the theoretical and practical implications of these findings.

Adult↗
PubMed2004

Self-recognition in everyday life.

INTRODUCTION: A sample of everyday difficulties was collected, encompassing errors and unusual experiences participants had encountered when recognising their own faces in everyday life, with the aim of characterising similarities and differences between the reported difficulties and the major forms of self-recognition impairments described in the neuropsychological and neuropsychiatric literatures (prosopagnosia, mirrored-self misidentification, and Capgras delusion). METHOD: A total of 70 participants recalled experiences from memory. Incidents (n = 51) were recorded on questionnaire sheets that were filled out at home. Reports of three categories of incidents were analysed: misidentifications (the participant misidentified her/his own face as being that of another familiar person; n = 5), recognition failures (the participant judged that his/her own face was that of an unfamiliar person; n = 20) and perception of unusual aspects (the participant confidently recognised his/her own face but found that the seen face did not fit well the representation she/he had of his/her own face; n = 26). RESULTS AND DISCUSSION: In the reported incidents, experiences showing some similarities to those of patients with prosopagnosia, Capgras delusion or mirrored-self misidentification were noted. However, across the whole study, no incident involved a failure of reality testing; in contrast to pathological forms of error, in all of the reported incidents from our study the participant realised that a mistake had been made. The importance of decision processes in pathological forms of own-face misrecognition is discussed.

Journal Article↗
PubMed2003

Further exploration memory bias in compulsive washers.

The aim of the present study was to replicate Radomsky and Rachman's findings on memory bias in obsessive-compulsive disorder (OCD), using the same procedure but an increased sample size, more specific control groups, and a full analysis of contamination attribution data. Sixteen OCD-washers, 16 OCD-checkers, 16 social phobic patients and 16 non-anxious controls were presented with 50 'clean' or 'dirty' objects. After this incidental encoding phase, participants were asked to freely recall the objects, to rate their anxiety when almost touching each object, and, finally, to attribute each object to one of the two contamination conditions ('clean' or 'dirty'). Verbal episodic memory was also assessed with the California Verbal Learning Test. The results indicate that, contrary to Radomsky and Rachman's findings, OCD-washers did not differ from the other participants in their memory for 'clean' and 'dirty' objects. However, the OCD-washers recalled more accurately the 'dirty' source of contamination than the 'clean' source. This result was specific to the OCD-washers, and suggests a memory bias for contextually threatening information. The differences between our findings and those published by Radomsky and Rachman's are discussed.

Adult↗
PubMed2003

Recognising the usual orientation of one's own face: the role of asymmetrically located details.

Our ability to recognise the usual horizontal orientation of our own face (mirror orientation) as compared with another very familiar face (normal orientation) was examined in experiment 1. Participants did not use the same kind of information in determining the orientation of their own face as in determining the orientation of the other familiar face. The proportion of participants who reported having based their judgment on the location of an asymmetric feature (eg a mole) was higher when determining the orientation of their own face than when determining that of the other familiar face. In experiment 2, participants were presented with pairs of manipulated images of their own face and of another familiar face showing conflicting asymmetric features and configural information. Each pair consisted of one picture showing asymmetric features of a given face in a mirror-reversed position, while the facial configuration was left unchanged; and one picture in which the location of the asymmetric features was left unchanged, while the facial configuration was mirror-reversed. As expected from the hypothesis that asymmetric local features are more frequently used for the judgment of one's own face, participants chose the picture showing mirror-reversed asymmetric features when determining the usual orientation of their own face significantly more often than they chose the picture showing normally oriented asymmetric features when determining the orientation of the other face. These results are explained in terms of competing forward and mirror-reversed representations of one's own face.

Adult↗
PubMed2003

Phenomenal characteristics of cryptomnesia.

Qualitative characteristics of cryptomnesia, or unintentional plagiarism were investigated. In Experiment 1 we compared accurate and inaccurate source attributions in terms of their level of confidence using instructions that did not require a fixed number of responses. Confidence was lower for plagiarised responses than for correct responses. Nevertheless, participants provided high ratings of certainty for a large proportion of their plagiarised responses. In Experiment 2 the phenomenological differences between plagiarised recall and veridical recall were compared by using an adaptation of the memory characteristics questionnaire (Johnson, Foley, Suengas, & Raye, 1988). Correct responses were associated with more experiential detail than plagiarised responses. However, a considerable number of plagiarised responses were accompanied by a confident memory of at least one qualitative characteristic. Results are discussed in terms of the source monitoring framework developed by Johnson, Hashtroudi, and Lindsay (1993).

Adolescent↗
PubMedDate not supplied

Preschoolers' use of form class cues to learn descriptive proper names.

This study examined 3- and 4-year-old preschoolers' ability to learn proper names containing familiar descriptions. Children saw a novel creature with a familiar property (it was red) and heard either an adjective ("This is a red one") or a descriptive proper name ("This is Mr. Red"). The creature was then transformed, losing the property (e.g., it became green). Children had to extend the word to either the transformed original creature or a new creature bearing the original property (another red creature). Children, especially 4-year-olds, extended the adjective to the new creature but were significantly more likely to extend the proper name to the original creature. Lexical form class cues provided potent information about word meaning, directing preschoolers to reinterpret familiar descriptive terms (adjectives) as homophonic terms designating unique individuals (proper names).

Association Learning↗