When engaged in what looks like child’s play, preschoolers are actually behaving like scientists, according to a new report in the journal Science: forming hypotheses, running experiments, calculating probabilities and deciphering causal relationships about the world.

The report’s author, Alison Gopnik, a psychologist at the University of California, Berkeley, says she based it on more than 10 years’ worth of research and studies, including some of her own.

In one study, for example, an experimenter performed five different sequences of three actions each, as a 4-year-old looked on. The sequences would either activate a toy or fail to activate it.

When the children were given the toy, they often performed only the actions required to activate it. They were able to eliminate the unnecessary actions by observation.