Vandana, a 12-month-old infant, is listening to her father talk to her and suddenly repeats a word that he just said. Her father praises her and gives her a cookie. After she gets the cookie, she...

Vandana, a 12-month-old infant, is listening to her father talk to her and suddenly repeats a word that he just said. Her father praises her and gives her a cookie. After she gets the cookie, she repeats the word again. Vandana’s behavior can be best explained by using the theory of