While young children may not fully understand the concept of sexism, they can exhibit gender-based preferences or biases based on their observations and experiences. These biases can be influenced by various factors, including cultural norms, parental attitudes, media representations, and peer interactions.

Here are a few examples of how sexism can manifest in four-year-olds:

1. Gender-Role Stereotyping: A four-year-old may associate certain activities, toys, or professions with specific genders. For instance, they might believe that cooking is for girls and playing with trucks is for boys. This can be influenced by the gendered messages they receive from parents, peers, and media.

2. Gendered Language: Four-year-olds may use gendered language, such as referring to boys as "strong" and girls as "pretty," even if they don't fully grasp the implications of these labels. They might pick up these linguistic patterns from the adults in their environment.

3. In-Group Favoritism: Children tend to favor members of their own group, and this can extend to gender-based in-group favoritism. For example, a four-year-old boy might prefer to play with other boys and exclude girls from their activities, not necessarily out of malice but because they feel more comfortable with boys.

It's important to keep in mind that sexism, or any form of bias, is not inherent in children but rather learned. However, early childhood is a critical period for shaping attitudes and beliefs, so it's essential to address gender biases and promote gender equality in the way we interact with and educate young children.