During the second year, children begin to show empathy to other people who are upset or hurt. By 18 months, children are becoming increasingly self-aware, and with this insight children are also becoming more aware of the feelings of others. In one study, a group of mothers pretended to be hurt or sad to see how their children would respond. By 18 months, many children attempted to bring comfort by patting/hugging, asking if their mothers were OK, or trying to bring bandages or a blanket. Although children may not show empathy every time, as they get closer to age 2 they tend to show empathy more and more.
Zahn-Waxler, C., Radke-Yarrow, K.,Wagner, E., & Chapman, M. (1992). Development of concern for others. Developmental Psychology, 28, 126