Infants' reactions to unfamiliar persons and novel objects.
D000339:Affect; D000367:Age Factors; D002657:Child Development; D003071:Cognition; D003220:Conflict, Psychological; D003448:Crying; D005106:Exploratory Behavior; D005149:Facial Expression; D005239:Fear; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D007223:Infant; D008297:Male; D009043:Motor Activity; D009949:Orientation; D012919:Social Behavior; D012931:Social Environment; D013637:Tape Recording; D013690:Television; D014796:Visual Perception