Study: Babies use logic at 12 months

In intriguing research, a team of scientists may have discovered the earliest age at which a person can reason logically: 12 months.

For decades, psychologists have considered language a necessary and essential indicator of inferential thinking — the complex ability to “read between the lines,” to reason one’s way to a correct interpretation of an event when the evidence is not obvious. As recently as 2014, experiments by prominent developmental psychologists suggested such thinking began from 3 to 5 years of age.

Psychologist Nicolo Cesana-Arlotti, a postdoctoral fellow at Johns Hopkins University, thought the age might be much younger.

“If you have logical reasoning, you can generate conclusions, you can obtain evidence that would be hard to obtain otherwise,” he explained this week. “It opens you up to much more information. So we were driven by the belief that logical reasoning might play an important role in a full picture” of the infant mind.

He and his colleagues were right.

In a study published this month in the journal Science, Cesana-Arlotti and his colleagues described how they determined infants might have inference-making ability.

Their experiment involved 144 babies, half of them a year old and half 19 months old, but none yet talking.