Department of Psychology, University of Miami, Coral Gables, Florida, USA.
Division of Applied Psychology, The Chinese University of Hong Kong, Shenzhen, China.
Dev Psychobiol. 2024 Sep;66(6):e22539. doi: 10.1002/dev.22539.
Infants' nonverbal expressions-a broad smile or a sharp cry-are powerful at eliciting reactions. Although parents' reactions to their own infants' expressions are relatively well understood, here we studied whether adults more generally exhibit behavioral and physiological reactions to unfamiliar infants producing various expressions. We recruited U.S. emerging adults (N = 84) prior to parenthood, 18-25 years old, 68% women, ethnically (20% Hispanic/Latino) and racially (7% Asian, 13% Black, 1% Middle Eastern, 70% White, 8% multiracial) diverse. They observed four 80-s audio-video clips of unfamiliar 2- to 6-month-olds crying, smiling, yawning, and sitting calmly (emotionally neutral control). Each compilation video depicted 9 different infants (36 clips total). We found adults mirrored behaviorally and physiologically: more positive facial expressions to infants smiling, and more negative facial expressions and pupil dilation-indicating increases in arousal-to infants crying. Adults also yawned more and had more pupil dilation when observing infants yawning. Together, these findings suggest that even nonparent emerging adults are highly sensitive to unfamiliar infants' expressions, which they naturally "catch" (i.e., behaviorally and physiologically mirror), even without instructions. Such sensitivity may have-over the course of humans' evolutionary history-been selected for, to facilitate adults' processing of preverbal infants' expressions to meet their needs.
婴儿的非言语表达——灿烂的笑容或尖锐的哭声——都具有很强的感染力。虽然父母对自己婴儿表情的反应相对容易理解，但在这里，我们研究了成年人是否更普遍地对产生各种表情的陌生婴儿的表情做出行为和生理反应。我们招募了即将成为父母的美国成年早期参与者（N=84），年龄在 18-25 岁之间，其中 68%为女性，在种族方面（20%为西班牙裔/拉丁裔）和民族方面（7%为亚洲人，13%为黑人，1%为中东人，70%为白人，8%为多种族）具有多样性。他们观察了四个时长 80 秒的陌生 2-6 个月大婴儿哭泣、微笑、打哈欠和安静坐着（情绪中性对照）的音频-视频片段。每个综合视频都描绘了 9 个不同的婴儿（共 36 个片段）。我们发现成年人在行为和生理上都有反应：婴儿微笑时他们会做出更积极的面部表情，婴儿哭泣时他们会做出更消极的面部表情和瞳孔扩张——这表明他们的警觉性增加。成年人在观察婴儿打哈欠时也会打哈欠更多，瞳孔扩张更大。这些发现表明，即使是非父母的成年早期参与者也对陌生婴儿的表情高度敏感，他们会自然而然地“捕捉”（即，在行为和生理上模仿）这些表情，即使没有指令。这种敏感性可能在人类的进化历史中被选择，以促进成年人对婴儿言语前表情的处理，以满足他们的需求。
