Mary Lee has been working on compliance. Given the same mand, in a 15-min. segment, Mary Lee complied with her teacher 4/5 times, her speech therapist, physical education teacher and mother 2/5 times. Six months later, given the same mand, in a 15-min. segment, Mary Lee complied with the bus driver 4/5 times, her physical therapist 4/5 times, the lunch lady 4/5 times and the vice-principal 4/5 times.
This scenario is an example of.