Washington: Children as young as 15 months can detect anger when watching other people's social interactions and then use that emotional information to guide their own behaviour, scientists say.
The study, by researchers at the University of Washington, is the first evidence that younger toddlers are capable of using multiple cues from emotions and vision to understand the motivations of the people around them.
"At 15 months of age, children are trying to understand their social world and how people will react," said lead author Betty Repacholi, a faculty researcher at UW's Institute for Learning and Brain Sciences and an associate professor of psychology.
"In this study we found that toddlers who aren't yet speaking can use visual and social cues to understand other people - that's sophisticated cognitive skills for 15-month-olds," she said.
The findings also linked the toddlers' impulsive tendencies with their tendency to ignore other people's anger, suggesting an early indicator for children who may become less willing to abide by rules.
In the experiment, 150 toddlers at 15 months of age - an even mix of boys and girls - sat on their parents' laps and watched as an experimenter sat at a table across from them and demonstrated how to use a few different toys.
Each toy had movable parts that made sounds, such as a strand of plastic beads that made a rattle when dropped into a plastic cup and a small box that "buzzed" when pressed with a wooden stick. The children watched eagerly - leaning forward and sometimes pointing enthusiastically.
Then a second person, referred to as the "emoter," entered the room and sat down on a chair near the table. The experimenter repeated the demonstration and the emoter complained in an angry voice, calling the experimenter's actions with the toys "aggravating" and "annoying."
After witnessing the simulated argument, the children had a chance to play with the toys, but under slightly different circumstances. For some, the emoter left the room or turned her back so she couldn't see what the child was doing.
In these situations, toddlers eagerly grabbed the toy and copied the actions they had seen in the demonstration.
In other groups, the angered emoter maintained a neutral facial expression while either watching the child or looking at a magazine.
Most toddlers in these groups hesitated before touching the toy, waiting about four seconds on average. And when they finally did reach out, the children were less likely to imitate the action the experimenter had demonstrated.
The study didn't factor in how much previous conflict children had seen at home or elsewhere, such as arguing parents or violent television shows.
However, Repacholi speculated that an emotionally charged home environment could make some children desensitised to anger, or others could become hypersensitive to it and overreact.