Does language, by providing a way to symbolize and communicate our thoughts, enable us to reason? Or are inference, deduction, and other forms of logical reasoning independent of our ability to put words to them? It’s hard to figure out whether babies can think, given they can’t tell us. Which makes separating language from reasoning even harder.

Ernő Téglás, at the Babylab in Budapest, researches “how infants acquire the conceptual sophistication necessary for abstract combinatorial thought involved in everyday reasoning.” His team has just published work describing the precursors of logical reasoning in pre-verbal infants; one group of infants was aged 12 months and the other was 19 months old. Babies at these ages are just at the cusp of language learning and speech development, but they definitely precede the development of extensive language.

Wrong expectations

Like 20-something adults given the same tests, these babies expressed distress when their deductions did not hold true. Distress came in the form of staring at the inconsistent outcomes, which is how baby cognition is often measured.