Detecting Emotional Faces In A Crowd:Contribution Factors To Happiness Superiority Effect

Happiness superiority effect(HSE),which refers to the individual’s discrimination and detection of happy facial expression is faster and more accurate than other emotional faces such as anger,fear and neutral expression,has the broadness and stability.Regarding the cause of HSE,the diagnostic value hypothesis was considered to be a diagnostic feature of a happy face(i.e.,the salient and distinctive feature of happy face,such as open mouth with visible teeth),rather than the facial configuration related to emotional semantic information that accelerates the discrimination and detection.The diagnostic value hypothesis was supported by a large body of research,especially evidence from facial expression discrimination task.Although the study of visual search tasks also widely confirmed it,its evidence is mainly derived from studies using a homogenous rather than heterogeneous crowd.Previous studies revealed that the homogeneity of distractors of visual array would influence the search strategy for a target.Therefore,this current study attempted to manipulate the homogeneity of distractors(identical,mixed distractors)and orientation of visual arrays(upright,inverted display),to explore the causes of HSE.This study mainly explored the expected hypothesis through four behavioral experiments which all consisted of a circular array of eight emotional face sets.One was to set up Experiment 1a(hybrid task)and 1b(block task)to explore HSE and its possible contribution factors in a homogenous crowd.Here,participants performed a discrepant target discrimination search in crowd of identical neutral faces,but which does not compulsorily require an identification.The second,Experiment 2 was examined HSE in a heterogeneous crowd,and whether the relevant contribution factors also undergo adaptive changes varied with the homogeneity of distractors.Participants performed a fixed emotional target detection in the heterogeneous crowd.The third is to set up Experiment 3,which is completely consistent with the content and form of Experiment 2.The only difference is that the happy expression material of Experiment 3 involved the smile without grin,while that of Experiment 2 contained the smiling toothy,so as to explore whether HSE can still be reflected in the heterogeneous crowd when lack of salient smile feature,and what factors contributed to it.Visual arrays were shown in both upright and inverted conditions.Inversion has been proven to dramatically disrupt configural processing while retaining featural processing,thus we could examine the specific processing method by measuring inversion effects.The results of Experiment 1a and 1b,though which have different variants of experimental setting,showed that HSE was observed,irrespective of visual orientation.RT for happy faces was no significant difference between upright and inverted display in both experiments,relative to which RT for angry(or fearful)faces in upright was invariably significant faster than inverted one.These illustrated that such a stable performance of HSE depends fully on the intrinsic perception properties of salient feature of happy expression.In contrast,there was significantly faster in upright than inverted condition for happy target detection in Experiment 2,although the results also revealed HSE regardless of the orientation.Further,Experiment 3 found that HSE only appears in the upright display.Experiment 2 and 3 together demonstrated the configuration of happy faces has also an imperative contribution factor to HSE in heterogeneous crowd,besides the facial salient feature that was indeed a key factor in social perception for HSE,rather than in its simply “pop-out” physical stimuli.In short,the use of salient featural processing of happy facial expression is a well shortcut of social perception to viewers’ search strategy,but the corresponding facial configuration is also necessary to the happiness preferential detection,particularly in an intricate search context.The above reflects a cognitive flexibility of human observers in the selective attention.