Facial expressions of Asian people exposed to constructed urban forests: Accuracy validation and variation assessment

Abstract

An outcome of building sustainable urban forests is that people’s well-being is improved when they are exposed to trees. Facial expressions directly represents one’s inner emotions, and can be used to assess real-time perception. The emergence and change in the facial expressions of forest visitors are an implicit process. As such, the reserved character of Asians requires an instrument rating to accurately recognize expressions. In this study, a dataset was established with 2,886 randomly photographed faces from visitors at a constructed urban forest park and at a promenade during summertime in Shenyang City, Northeast China. Six experts were invited to choose 160 photos in total with 20 images representing one of eight typical expressions: angry, contempt, disgusted, happy, neutral, sad, scared, and surprised. The FireFACE ver. 3.0 software was used to test hit-ratio validation as an accuracy measurement (ac.) to match machine-recognized photos with those identified by experts. According to the Kruskal-Wallis test on the difference from averaged scores in 20 recently published papers, contempt (ac. = 0.40%, P = 0.0038) and scared (ac. = 25.23%, P = 0.0018) expressions do not pass the validation test. Both happy and sad expression scores were higher in forests than in promenades, but there were no difference in net positive response (happy minus sad) between locations. Men had a higher happy score but lower disgusted score in forests than in promenades. Men also had a higher angry score in forests. We conclude that FireFACE can be used for analyzing facial expressions in Asian people within urban forests. Women are encouraged to visit urban forests rather than promenades to elicit more positive emotions.

Optimizing Urban Forest Landscape for Better Perceptions of Positive Emotions

“…This is in accordance with findings that happy scores had a negative relationship with sad scores. Photos of unaware pedestrians did not show any differences between male adolescents and other groups of visitors in urban forest parks [29,39]. However, an enormous survey interviewing 200,000 teenagers from 42 European countries also suggested that male adolescents looked happier than female adolescents [47].…”

“…Gender was categorized into female and male according to visual perceptions of sexual characteristics. Age was categorized into five ranges: toddler (1-5 years-old), adolescent (6-19 years-old), youth (20-25 years-old), middle-aged (35-50 years-old), and senior (over 60 years-old) [39,40].…”

“…Two basic facial expressions, happy and sad, were recognized and rated by the instrument. These two emotional expressions were used since they have the highest accuracy among all facial expressions [39]. We used a new variable to assess the net presentation of positive emotion (i.e., positive response index (PRI)), that is evaluated as happy score minus sad score [27,29,32,35].…”

Robustness of the aging effect of smiling against vertical facial orientation

“…This is because, for example, in the circumplex affect model, the surprise is neutral in valence but not in arousal (Russell & Barrett, 1999). Moreover, a recent study on facial expressions reported that surprised and neutral faces were mapped separately (Guan, Wei, Hauer, & Liu, 2021). Therefore, we avoided claims about neutral emotions in surprised faces.…”

Facial Expressions and Self-Reported Emotions When Viewing Nature Images

“…To date, automated facial expression recognition has rarely been used in environmental psychology research. In a series of experiments conducted by Wei and his colleagues [ 25 , 26 , 40 , 41 ], participants were asked to take selfies or were photographed while walking on urban streets or in a forest park. The photographs were analyzed using FireFACE software.…”