More than a hundred 3-year-olds of various socioeconomic levels took part in the study by researchers at the University of Delaware and Temple University.
Children who were better at copying block structures were also better at early math, the study found.
Among the skills tested were whether children could figure out that a block belongs above or below another block and whether they aligned the pieces.
The study also found that by age 3, children from lower-income families were already falling behind in spatial skills, likely as a result of more limited experience with blocks and other toys and materials that facilitate the development of such skills.
And parents of low-income toddlers reported using significantly fewer words such as "above" and "below" with their children.
Blocks are affordable and enjoyable, and they're easily used in preschool settings. Giving children-especially those from low-income families-such toys to play with can help them develop skills that will have long-lasting effects on later STEM-related educational outcomes, the researchers suggest.
The study is published in the journal Child Development.