Attentional capture of emotional static and dynamic hand gestures and faces : the effect of valence in a novel stroop-based paradigm

Abstract

Task-irrelevant static emotional faces, pictures, and words are known to involuntarily receive or capture attention. Hand gestures, similar to faces, are biological stimuli that are often used to express emotion. This thesis examines attentional capture using static emotional hand gestures and dynamic emotional hand gestures and faces. The component processes model of emotion predicts that either positive or negative stimuli that are appraised as relevant will capture attention for further and deeper processing. Attentional capture and the resulting competition for resources to process emotional stimuli can cause interference with an ongoing implicit cognitive task. In a series of experiments, participants identified the gender of hand or face stimuli while neutral, positive, and negative valence of stimuli was manipulated. It was hypothesised that interference resulting from attentional capture would lead to greater gender identification accuracy for static neutral hand gestures than for static positive or negative hand gestures. Neutral and emotional static faces were used as comparison stimuli. The hypothesis was tested in six experiments using a novel Stroop-based experimental paradigm, specifically devised for future implementation in Magnetoencephalography (MEG) environment. Stimulus items were presented to the peripheral visual field in one of four quadrants for 100 ms (Experiments 1 and 4), 200 ms (Experiment 2), and 300 ms (Experiment 3) each, in trials of eight items with an inter-stimulus interval (ISI) that varied from 1800 to 2300 ms. As hypothesised, accuracy of identifying neutral hand gestures was significantly greater than accuracy of identifying gender of positive or negative hand gestures. The hypothesis was also supported for the case of negative faces but not for positive faces. The lack of an effect in response to positive faces is possibly due to the valence ambiguity of neutral faces capturing attention and interfering with gender identification. Experiment 5 examined attentional capture using emotional static hand gestures and faces presented to the central visual field. Only positive hand gestures and positive faces captured attention in this experiment. Experiment 6 tested two hypotheses using dynamic stimuli presented in the peripheral visual field for 300 ms. The hypothesis that greater gender identification accuracy would be found for neutral hand gestures/faces than for positive or negative hand gestures/faces was supported for positive hand gestures and negative faces, but not for negative hand gestures and positive faces. A second hypothesis was that greater attentional capture and resulting interference from dynamic stimuli would lead to poorer gender identification accuracy for emotional dynamic stimuli than for emotional static stimuli. The results of Experiment 6 did not support this hypothesis. These six experiments demonstrate that both static and dynamic positive and negative hand gestures and dynamic negative faces capture attention and interfere with an ongoing cognitive task when presented to the peripheral visual field. The experiments also demonstrate that static positive hand gestures and static positive faces capture attention when presented to the central visual field. Moreover, the novel Stroop-based experimental design appears to be a useful method for studying attentional capture using emotional pictorial stimuli and has already been implemented in a companion MEG experiment. A model explaining attentional capture and interference using emotional stimuli is proposed, based on the component processes model of emotion. In the model, the degree of attention recruited during the primary appraisal is proportional to the degree of interference with an implicit cognitive task