In this chapter, we have looked at the development of cognitive, language-based and social skills in relation to development during the early years. We have also evaluated the methods used to examine development, especially in young infants. Hopefully, you should now be able to reflect on the appropriateness of these different methodologies and to question the types of conclusion drawn from studies using these methods.

One of the main questions we have discussed is the validity of researchers’ interpretations of research evidence concerning infants’ early mental and cognitive capabilities. As we have illustrated, though results from experiments may often be replicated, interpretations of these results may vary according to the nature of the study.

Finally, we have illustrated how the interaction between genes and the environment should be seen as a complex relationship. Through this interaction, infants can begin to develop a better sense of the social world, through the development of mental representations, language skills and social relationships.