Age and gender effects on the human’s ability to decode posed and naturalistic emotional faces

This paper proposes a systematic approach to investigate the impact of factors such as the gender and age of participants and gender, and age of faces on the decoding accuracy of emotional expressions of disgust, anger, sadness, fear, happiness, and neutrality. The emotional stimuli consisted of 76 posed and 76 naturalistic faces, differently aged (young, middle-aged, and older) selected from FACES and SFEW databases. Either a posed or naturalistic faces’ decoding task was administered. The posed faces’ decoding task involved three differently aged groups (young, middle-aged, and older adults). The naturalistic faces’ decoding task involved two groups of older adults. For the posed decoding task, older adults were found significantly less accurate than middle-aged and young participants, and middle-aged significantly less accurate than young participants. Old faces were significantly less accurately decoded than young and middle-aged faces of disgust, and anger, and young faces of fear, and neutrality. Female faces were significantly more accurately decoded than male faces of anger and sadness, significantly less accurately decoded than male faces of neutrality. For the naturalistic decoding task, older adults were significantly less accurate in decoding naturalistic rather than posed faces of disgust, fear, and neutrality, contradicting an older adults’ emended support from a prior naturalistic emotional experience. Young faces were more accurately decoded than old and middle-aged faces of disgust and anger and old faces of neutrality. Female faces were significantly more accurately decoded than male faces of fear, and significantly less accurately decoded than male faces of anger. Significant effects and significant interdependencies were observed among the age of participants, emotional categories, age, and gender of faces, and type of stimuli (naturalistic vs. posed), not allowing to distinctly isolate the effects of each involved variable. Nevertheless, the data collected in this paper weakens both the assumptions on women enhanced ability to display and decode emotions and participants enhanced ability to decode faces closer to their own age (“own age bias” theory). Considerations are made on how these data would guide the development of assessment tools and preventive interventions and the design of emotionally and socially believable virtual agents and robots to assists and coach emotionally vulnerable people in their daily routines