Abstract Studies have demonstrated that a forest experience can improve the mental state of visitors. The questionnaire methodology accounts for most of current findings, but subjective bias in self-reported scores cannot be eliminated. In this study, FireFACE V3.0 software was used to evaluate facial expressions of visitors unconsciously entering (urban experiencer) or leaving an urban forest park (forest experiencer) from 9:00 am to 5:00 pm. A total of 458 photos were tested for the hit-rate of machine-recognized facial expression scores to those identified by experts. Neutral, happy, sad, and scared expressions passed the validation test and were used for further analysis. The positive response index (PRI) was calculated as the difference between happy and sad scores. All five variables were analyzed by a mixed-model analysis of variance of walking direction (into the park vs. out of the park), gender (male vs. female), and age (senior, middle-aged, and young) on repeated records every 30 min in a daytime except noon. In the morning, pedestrians walking out of the forest park did not show more positive expressions than those leaving the park. Young visitors walking through the exit averaged a higher sadness score but a lower PRI than middle-aged visitors. In the afternoon, middle-aged visitors walking through the entrance averaged a higher PRI relative to young visitors leaving the park in the morning. Compared to urban experiencers, forest experiencers averaged lower scores for neutral and scared expressions, but forest experiencers unlikely revealed more positive expressions. Therefore, a forest experience does not always evoke positive expression on unconscious faces which was a responsive variable to go with time. Middle-aged people are encouraged to walk in forests with a longer time than youths in the morning. Male visitors, especially those in senior ages, are suggested to spend more time in forests than females.

中文翻译：

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森林体验并不总是能唤起积极情绪：使用面部阅读技术对无意识面部表情进行试点研究

摘要 研究表明，森林体验可以改善游客的心理状态。问卷方法占了当前调查结果的大部分，但无法消除自我报告分数中的主观偏见。本研究使用FireFACE V3.0软件对上午9:00至下午5:00无意识进入（城市体验者）或离开城市森林公园（森林体验者）的游客面部表情进行评估。对 458 张照片进行了机器识别面部表情分数与专家识别的匹配率测试。中性、高兴、悲伤和害怕的表情通过了验证测试并用于进一步分析。积极响应指数 (PRI) 计算为快乐和悲伤分数之间的差异。所有五个变量均通过步行方向（进公园与公园外）、性别（男性与女性）和年龄（老年、中年和青年）的方差的混合模型分析进行分析。除中午外，白天每 30 分钟记录一次。早晨，走出森林公园的行人并没有比离开公园的人表现出更多积极的表情。与中年游客相比，年轻游客走过出口的平均悲伤分数更高，但 PRI 更低。与早上离开公园的年轻游客相比，下午穿过入口的中年游客的平均 PRI 更高。与城市体验者相比，森林体验者在中性和害怕表情的平均得分较低，但森林体验者不太可能表现出更积极的表情。所以，森林体验并不总能在无意识的脸上唤起积极的表情，这是一个随时间变化的响应变量。鼓励中年人早上在森林中行走的时间比年轻人长。建议男性游客，尤其是年长者，比女性游客多花些时间在森林里。