Tyra is babysitting their sister's infant daughter when the mail arrives. There is a package to be signed for, and Tyra asks the carrier to step inside because of the weather. The carrier smiles at Tyra's niece, who hides their face in Tyra's shoulder and then looks back at the carrier with concern. What has happened here?
Separation anxiety was expressed in tears, dismay, or anger when a familiar caregiver left.
Infants progress from reactive pain and pleasure which then lead to complex patterns of social awareness.
Stranger wariness occurred when an infant expressed concern when an unknown person appeared.
Happiness was expressed by the social smile, evoked by a human face.