A study was done with 30 three-year-old children and their parents. Half of the children participated in the experimental study; the other half acted as the control group. In the experimental group, the parents were given a two-hour training session in which they were taught to ask open-ended questions rather than yes-or-no questions. For example, the parent should ask, “What is the doggie doing?” rather than “Is the doggie running away?” The parents in the experimental group were also instructed in how to help children find answers, how to suggest alternative possibilities and how to praise correct answers. Question:The difference between the control group and the experimental group was __________.