OS_13. Face recognition
Friday, September 30th, 2011 [14:20 - 16:00]
OS_13.1 - Temporal integration of faces learned from view sequences and recognition of novel views
Arnold, G. & Sieroff, E.
Institut de Psychologie, Université Paris Descartes, CNRS, FRANCE
When faces are learned from rotating view sequences, novel views may be recognized by matching with multiple discrete views, or with an integrated representation of the sequence. A view-matching process should benefit from long view durations, allowing the attention to sequentially focus on each view during the encoding of the sequence. Conversely, an integrated-representation process should benefit from short view durations, allowing the distribution of attention over the entire sequence in a short temporal window. In a sequential comparison task, we tested the recognition of novel interpolated and extrapolated views after learning faces from rapid (240 ms for each view) and slow sequences (960 ms for each view). In a first experiment, recognition was tested with internal views (learned and interpolated). In a second experiment, recognition was tested with internal and extrapolated views. Results showed a global superiority of rapid over slow sequences, in favour of the integrated-representation hypothesis. In addition, the recognition pattern for the different viewpoints in the sequence depended on the absence (Experiment 1) or presence (Experiment 2) of extrapolated test views. The presence of extrapolated views affects the global representation of the face, modifying the “centre of gravity” of the representation.
OS_13.2 - Early perceptual processing of facial expression is independent of task demands: an event-related potentials study
Aguado, L. , Valdes-Conroy, B. & Fernandez-Cahill, M.
UNIVERSIDAD COMPLUTENSE DE MADRID
Extensive previous evidence from event-related potential (ERP) studies has shown that early components sensitive to visual encoding of faces are modulated by their emotional expression, suggesting that affective relevance influences perceptual processing since the earliest stages of information analysis. In this study we looked at the influence of differences in task demand on these modulations. Happy, angry and expressively neutral faces were presented under three different task conditions, 1) emotion discrimination (emotional vs non-emotional), 2) gender discrimination and 3) irrelevant task (discriminating two symbols placed over the nose region). Supporting previous work we found significant modulations due to emotional expression on the P100, N170 and EPN (early posterior negativity) components, detected over posterior regions. A right-lateralized, late positive component (LPC), detected over posterior regions around 400 ms after stimulus onset, appeared to be sensitive only to task demands, with larger amplitudes for the emotion discrimination task. A lack of interactions between emotional expression and task demands suggests that the influence of facial expression on perceptual processing takes place regardless of the explicit orientation to the affective meaning of faces. Supported by grant PSI2010_18682, of the Ministerio de Ciencia e Innovación (Spain)
OS_13.3 - Brain and language acquisition research: Construction of recursive exercises for non verbal communication devices
Lowenthal, F. 1 , Fortemps, P. 2 & Wautie, V. 1, 2
1 Cognitive Sciences, University of Mons, Mons (BE)
2 Mathematics and Operational Research, University of Mons, Mons (BE)
One of us (FL) has shown that Non-Verbal Communication Devices approaches (NVCDs) favor both the acquisition and the reacquisition of language skills (Lowenthal & Saerens, 1986). Lefebvre et al. (2007) have shown that these approaches favor the emergence of new cerebral abilities. Lowenthal (2007) formulate the hypothesis that these results are essentially associated to the use of recursive exercises in an NVCD approach. In order to test this hypothesis, the authors want to use finite automata enabling the subject to discover the regularity of the sequence of exits: they want to use in parallel non recursive, partially recursive and fully recursive exercises in three different but equivalent groups. This requires the construction of equivalent exercises of different types: clearly recursive, partially recursive and totally non recursive. For the researcher, the creation of such exercises is an arduous task. In this paper we describe a systematic and algorithmic approach for constructing such exercises. We will present a software adapted for these constructions. The intended experimental setting will also be discussed.
OS_13.4 - Congruency of cue and task transitions in task switching
Vandierendonck, A. 1 & Liefooghe, B. 2
1 Department of Experimental Psychology. Ghent University. Ghent, Belgium
2 Department of Experimental-Clinical and Health Psychology. Ghent University. Ghent, Belgium
Previous research regarding the role of congruency of cue and task transitions in task switching has shown that in transition cuing with registration of cue interpretation besides task execution (double registration) reports a cue-task congruency effect in cue interpretation. By varying type and modality of the indication response, the present study aimed to clarify whether the cue-task congruency effect depends on procedural features. In two transition cuing experiments with double registration, the cue interpretation response was either a choice response indicating the task or a simple response indicating when the to-be-performed task is known. Experiment 1 used manual indication responses and observed a congruency effect that occurred in the indication response for the choice-response condition and in the execution response for the simple-response condition with an overall delay of execution responding. Experiment 2 used verbal indication responses and found the same pattern of results, with smaller but still robust congruency effects and no execution delay in the simple-response condition. The findings confirm that the congruency effect is a genuine part of task switching but that it can be augmented by overlaps between the indication and the execution response. Implications for our understanding of task switching more generally are discussed.