Johnson was cast as Blue's voice because, of the show's crew, she was able to sound the most like a dog.
The producers used a variety of formal features, which were auditory, and content features, which consisted of invitations given to the audience.
They purposely presented the problem presented in increasing levels of difficulty, to prevent children from feeling frustrated and to master concepts, experience success, and feel empowered to attempt to solve more challenging concepts presented to them.
Troseth and her colleagues at studied how toddlers used information gained from prerecorded video and from interactions with a person through closed-circuit video, and found that two-year-old children did not learn as much from prerecorded videos because the videos lacked social cues and personal references.
Santomero, who named as a major influence, worked at Nickelodeon as a researcher and Johnson was a freelance artist and animator.
Some fans wondered whether he had gone to jail or turned to drugs.