Article 2 Emotions 2 Female 2 Humans 2 adult 2 controlled study 2 corrugator supercilii muscle emotion 2 face muscle 2 facial expression 2 female 2 human 2 young adult 2 zygomaticus major muscle 2 Adolescent 1 Analysis of Variance 1 Caregiving 1 Child 1 Electrodes 1 Electromyography 1 Empathy 1 Endocrinology 1 Face 1 Facial Muscles 1 Hormones 1 Infant 1 Male 1 Muscles 1 Preliminary Data 1 Self-Injurious Behavior 1