The first time four-year-old Savannah attempted to make her bed, her father praised her for covering the pillow with a blanket. After a few times, her father began praising Savannah for covering the pillow and tucking in the corners of the sheet. Finally, Savannah's father praised her when she covered the pillow, tucked in the corners of the sheet, and smoothed the blanket. The process described in this scenario is known as