It seems that even very young children are aware when we break our promises or make weak excuses for failing to deliver on a promise.   Children as young as 3 years recognise that some excuses are better than others and by the time they reach preschool age, they understand that some reasons for having to break promises are more reasonable than others.

Leon Li, who did the research with developmental psychologist Michael Tomasello as part of his Ph.D. in psychology and neuroscience at Duke.

Leon Li and Michael Tomasello published the results of a study in the journal Cognitive Development.   They showed a group of 3 – 5 year olds a series of videos featuring puppets who promised to show them a toy but then after leaving the scene, returned empty-handed.

Afterwards, the puppets either gave a good excuse for going back on their word (“I had to help my friend with his homework”), a bad excuse (“I wanted to watch TV”), or no explanation at all. The children were then asked whether they thought the puppets’ actions were wrong or not, and why.

No matter what the excuse (or lack thereof), the children agreed that it was generally wrong to break a promise. But they were more understanding when the puppets offered a good excuse (i.e., they had to help someone), versus a lame one (i.e., they just wanted to do something fun instead).

As Li wrote, children this age grasp that obligations to help others take priority over selfish desires.

The children’s responses also revealed that a lame excuse was just as bad as none at all.

“Previous research has suggested that in some cases, young kids will just take any reason to be better than no reason at all,” Li said. “But here we showed that kids do pay attention to the actual content.”

Children’s explanations of their answers differed with age. Compared with three-year-olds, five-year-olds were better at expressing their thoughts of what the puppets “should” do, or are “supposed” to do, suggesting that understanding of obligations to others is more fully developed by this age.

Surprisingly, poor excuses didn’t make the children less inclined to say they “liked” some puppets, or would invite those puppets to a play date.

“Usually if someone breaks a promise and gives you a lame reason, it implies they’re not really a good friend,” Li said. “Children this age don’t make that connection. They’re just not there yet.”

Li said the findings are also relevant to any adult who has uttered the classic fallback phrase, “Because I said so.”

“Kids are paying attention and can tell that is a lame reason,” Li said.

More information: Leon Li et al, Young children judge defection less negatively when there’s a good justification, Cognitive Development(2022).  DOI: 10.1016/j.cogdev.2022.101268