Abstract The present thesis addresses whether and how some of the information conveyed by faces affects selective attention. This is an important question as faces convey a rich source of affective and social information, playing a key role in social cognition. Specifically, facial expressions allow us to draw inferences about individuals’ emotional state, whereas the direction of eye gaze provides information about others’ interests and focus of attention. Across five studies, and a total of 11 experiments, the question of whether processing these facial signals is efficient and it affects selective attention is investigated. More specifically, after a brief review of the theories on face processing that are most relevant to the work reported in the present thesis (Chapter 1) and a review of the empirical evidence (Chapter 2), the first two studies used a Rapid Serial Visual Presentation paradigm to investigate the effect of emotional faces on temporal selective attention (Chapter 3). Study 1 showed that briefly presented positive (happy) and negative (angry) target faces differently affect temporal selective attention already at early lags (i.e., 83-166 ms). Study 2, revealed that the early valence-effect on temporal attention occurs also when using task-irrelevant positive (happy) and negative (fearful) hybrid stimuli, obtained by masking an emotional expression conveyed only at Low Spatial Frequency (LSF) with a neutral expression conveyed at high spatial frequency. Study 3 (Chapter 4) investigated whether affective evaluations of emotional expressions (happy, angry, fearful, surprised and neutral faces) are modulated by gaze direction (straight gaze, directed to the observer or averted gaze, away from the observer) when the face stimulus is presented rapidly (300 ms) in full broadband (Exp.1) or in the hybrid version (Exp.2). Findings showed that regardless of the affective content visibility, both facial expression and gaze direction modulate participants’ responses, but they did so independently. In study 4, (Chapter 4) the effect of gaze direction on observer’s overt (eye movement) orienting was investigating using faces embedded in complex scenes. Eyes movements results showed that participants spontaneously (during a free viewing task) follow the gaze direction of the face 4 depicted in the scene and this gaze following response occurred also when the scene was presented rapidly (during a visual search task) and without overt attention on the face. Finally, in study 5 (Chapter 5), a static (Exp. 1 and 2) and dynamic (Exp.3 and 4) gaze cueing task were used to investigate whether gaze direction and facial expression differently affect observer’s attention in older (Exp. 1 and 3) and young (Exp. 2 and 4) adults. Results showed preserved gaze following in old adults, although it was reduced compared to young adult for static cues only. Interestingly, in all experiments, facial expressions did not modulate gaze following response in young adults, whereas it did in older adults, indicative of an age-related emotion regulation strategy (i.e., positivity bias). In summary, the experimental evidence reported in the present thesis showed that individuals are highly sensitive to expression and gaze information, and that they are able to rapidly and efficiently process these facial signals even in condition of constrained attention (i.e., when they are rapidly presented in a stream of distractor-stimuli, when facial expression are filtered at LSF and masked by a neutral expression, when gaze direction is presented peripherally, out of the attentional focus, or it is presented centrally but it is task-irrelevant). In addition, the ability to process socio-affective signal from faces is preserved in older, healthy adults, especially when a more ecological procedure is used (dynamic cues) and it is indicative of attention deployment strategy toward positive signals from young, unfamiliar people and away from positive signals from their unfamiliar peers.

Facing Faces: the influence of facial expression and gaze direction on selective attention / Monachesi, Bianca. - (2019 Feb 22).

Facing Faces: the influence of facial expression and gaze direction on selective attention

MONACHESI, BIANCA
22/02/2019

Abstract

Abstract The present thesis addresses whether and how some of the information conveyed by faces affects selective attention. This is an important question as faces convey a rich source of affective and social information, playing a key role in social cognition. Specifically, facial expressions allow us to draw inferences about individuals’ emotional state, whereas the direction of eye gaze provides information about others’ interests and focus of attention. Across five studies, and a total of 11 experiments, the question of whether processing these facial signals is efficient and it affects selective attention is investigated. More specifically, after a brief review of the theories on face processing that are most relevant to the work reported in the present thesis (Chapter 1) and a review of the empirical evidence (Chapter 2), the first two studies used a Rapid Serial Visual Presentation paradigm to investigate the effect of emotional faces on temporal selective attention (Chapter 3). Study 1 showed that briefly presented positive (happy) and negative (angry) target faces differently affect temporal selective attention already at early lags (i.e., 83-166 ms). Study 2, revealed that the early valence-effect on temporal attention occurs also when using task-irrelevant positive (happy) and negative (fearful) hybrid stimuli, obtained by masking an emotional expression conveyed only at Low Spatial Frequency (LSF) with a neutral expression conveyed at high spatial frequency. Study 3 (Chapter 4) investigated whether affective evaluations of emotional expressions (happy, angry, fearful, surprised and neutral faces) are modulated by gaze direction (straight gaze, directed to the observer or averted gaze, away from the observer) when the face stimulus is presented rapidly (300 ms) in full broadband (Exp.1) or in the hybrid version (Exp.2). Findings showed that regardless of the affective content visibility, both facial expression and gaze direction modulate participants’ responses, but they did so independently. In study 4, (Chapter 4) the effect of gaze direction on observer’s overt (eye movement) orienting was investigating using faces embedded in complex scenes. Eyes movements results showed that participants spontaneously (during a free viewing task) follow the gaze direction of the face 4 depicted in the scene and this gaze following response occurred also when the scene was presented rapidly (during a visual search task) and without overt attention on the face. Finally, in study 5 (Chapter 5), a static (Exp. 1 and 2) and dynamic (Exp.3 and 4) gaze cueing task were used to investigate whether gaze direction and facial expression differently affect observer’s attention in older (Exp. 1 and 3) and young (Exp. 2 and 4) adults. Results showed preserved gaze following in old adults, although it was reduced compared to young adult for static cues only. Interestingly, in all experiments, facial expressions did not modulate gaze following response in young adults, whereas it did in older adults, indicative of an age-related emotion regulation strategy (i.e., positivity bias). In summary, the experimental evidence reported in the present thesis showed that individuals are highly sensitive to expression and gaze information, and that they are able to rapidly and efficiently process these facial signals even in condition of constrained attention (i.e., when they are rapidly presented in a stream of distractor-stimuli, when facial expression are filtered at LSF and masked by a neutral expression, when gaze direction is presented peripherally, out of the attentional focus, or it is presented centrally but it is task-irrelevant). In addition, the ability to process socio-affective signal from faces is preserved in older, healthy adults, especially when a more ecological procedure is used (dynamic cues) and it is indicative of attention deployment strategy toward positive signals from young, unfamiliar people and away from positive signals from their unfamiliar peers.
22-feb-2019
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1263478
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