New research shows that preschoolers can detect logical inconsistencies

Do preschoolers understand logic? Do they understand that something cannot be both true and false at the same time?

That’s what new research published in Child Development set out to discover. The findings are surprising.

The study, led by Ph.D. graduate Sabine Doebel and associate professor Melissa Koenig of the University of Minnesota’s Institute of Child Development, found that children as young as 4 years old can detect logical inconsistency if the claims they are evaluating are presented in verbal context that encourages children to think about speakers’ reliability as information sources. In addition, the research indicated that “executive function,” or the ability to override habits or impulses, helped 4- and 5-year-olds detect inconsistencies in adult speakers.

Previous research had suggested that children younger than 6 years of age cannot detect logical inconsistency. This new research, however, provides new insights about when and how foundational logical skill first emerges in children and what role it plays in supporting early social learning.

Sabine Doebel

“This research gives us a more accurate sense of when children can detect logical inconsistencies and what skills seem to support it, which in turn provides new ideas about how this key ability might continue to develop into adulthood,” said Doebel. “The study also provides new evidence of social influences on reasoning. If we want children and adults to reason well, it may be beneficial to provide information in social contexts that support and motivate reasoning, rather than presenting information in abstraction.”

In one of the study’s experiments, 3- to 5-year-olds were presented with two speakers who expressed claims that were logically consistent and inconsistent. For example, one speaker said, “This box is full of toys and it has a ball in it,” while the other speaker said, “This box is full of toys and it is empty.” The 4- and 5-year-olds correctly identified the inconsistent speaker as not making sense.

In a second experiment, children were given the opportunity to detect logical inconsistencies either spoken or read from books by adults. Four-year-olds only detected logical inconsistencies when they were expressed by speakers; 5-year-olds detected them in both contexts.

In both experiments, children remembered when speakers were inconsistent and avoided learning new information from them. The second experiment also found that executive function, when controlled for verbal knowledge and working memory in the children, predicted inconsistency detection over and above the control variables.

“Executive function plays a role in many early emerging skills, and others have suggested it might be important for other logical concepts,” said Doebel. “More research is needed to understand exactly how this might work. Interventions to train executive function have shown a lot of promise, and it would be great if such training could promote logical skills.”

The study, “Young Children Detect Logical Inconsistency: Roles for Social Learning and Executive Function,” was funded by the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health, and the National Science Foundation.