Paul Bloom talks about research on the morality of small children, and ways in which their morality is similar to and different from adults. Concise descriptions of supporting experiments is given throughout.
Basically, babies prefer nice people over mean people, but prefer people who punish mean people over people who reward mean people. But babies are not impartial; for example, they give favorable treatment to other babies who are wearing the same tee-shirt as themselves.
Also has some content about the cognition of babies in general. Experiments show that, at various young ages, “..babies think of objects largely as adults do, as connected masses that move as units, that are solid and subject to gravity and that move in continuous paths through space and time,” and “…expect people to move rationally in accordance with their beliefs and desires…”, and “…know that other people can have false beliefs”.