When Jack was 3 years old, if asked his gender, he would call himself a boy or a girl with equal frequency. After another year or two, however, he became more consistent in identifying himself as a boy. Now 7 years old, Jack is confident about his identity as a boy and wants to take a dance class that has many more girls than boys in it. Which concept is being illustrated here: gender schemas, gender stereotypes, gender roles, or cognitive development theory? Please explain your choice.