Use your knowledge of cognitive explanations for gender development to explain the comments made by Sophia and Marcus in the dialogue below.

Sophia and Marcus Dialogue

Sophia and Marcus are talking about Sophia’s four-year-old son, Toby.

Sophia: "It's funny how they think at that age. Last year, Toby genuinely believed that his cousin Lily would actually become a boy if she cut her hair short and wore a football kit."

Marcus: "I know! And now he's four, he’s constantly categorising things into 'boy things' and 'girl things'. He won't touch the toy baking set because he says it's 'not for boys', and he spends all his time closely watching his older brother to copy exactly how he plays with monster trucks."