Can we observe spontaneous smiles in 1-year-olds?

• Published in: Infant behavior & development Vol. 32; no. 4; pp. 416 - 421
• Main Authors: Kawakami, Fumito, Kawakami, Kiyobumi, Tomonaga, Masaki, Takai-Kawakami, Kiyoko
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.12.2009; Elsevier
• Subjects: 1 year-olds; Aging - psychology; Biological and medical sciences; Child Development - physiology; Emotion; Facial Expression; Female; Functional Laterality - physiology; Fundamental and applied biological sciences. Psychology; Humans; Infant; Infant Behavior - psychology; Laughter - psychology; Male; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Smiling - psychology; Social smiles; Spontaneous smiles; Spontaneous smiles; Emotion; 1 year-olds; Social smiles; Facial expression; Human; Affect affectivity; Spontaneous; Infant; Emotion emotionality; Face; Smile
• ISSN: 0163-6383; 1879-0453; 1934-8800
• DOI: 10.1016/j.infbeh.2009.07.005

Five infants were observed longitudinally. In over 30 h of observations, seven spontaneous smiles and one spontaneous laugh were found. All smiles were observed in infants between the ages of 10 and 15 months. These data indicate that spontaneous smiles do not disappear at 2 months of age and they still exist at over 15 months. This disproves some emotional expression theories, where spontaneous smiles are considered to be precursor to and replaced by social smiles. Our data suggest that those theories must be revised and provide new perspectives on this field of studies.