Conceptual knowledge increases infants' memory

Fourteen month old babies, the same as adults, remember only three things at a time, and get past this limitation by categorising.

When researchers helped the babies group toys in spatially separate groups, or naming them with different nonsense words, then the babies remembered when there were more than three and kept looking

(Proceedings of the National Academy of Sciences, DOI: 10. 1073/prias.0709884105)

Lisa Feigenson et al., Babies use grown-up memory tricks, New Scientists (Print Edition), July 19, 2008.