and mislead young children. Shortly before the show's premiere, the producers created five one-hour episodes so that they could test if children found them comprehensible and appealing. They were never intended for broadcast, but were presented to preschoolers in 60 homes throughout Philadelphia in July 1969. The producers found that the results were "generally very positive". However, children attended to the shows during the Muppet segments, but their interest was lost during the street scenes, which featured only humans and were considered "the glue" that "pulled the show together". The appeal of the test episodes was lower than they preferred, so the producers re-shot the street segments. Henson and his team created Muppets that could interact with the human actors; specifically, as the show's researchers put it, "two of Sesame Streets most enduring Muppets: Oscar the Grouch and Big Bird". The test episodes were responsible for what writer Malcolm Gladwell called "the essence of Sesame Street—the artful blend of fluffy monsters and earnest adults". CTW researcher Gerald Lesser called the producers' decision to defy the recommendations of their advisers "a turning point in the history of Sesame Street". Animation, films, and other media Animation was another important aspect of the structure of Sesame Street. Lesser stated that one of the purposes of animation was to create incongruity, or what he called "illogical surprises". The first piece of animation commissioned by the CTW for Sesame Street was "the J commercial", in 1968, which they used in a study about its effectiveness in daycare centers in New York City. The CTW found that it was an effective tool in teaching children letters and numbers and that it effectively attracted children's attention. It also provided evidence, as writer Robert W. Morrow reported, that children were able to "endure enormous amounts of repetition". According to Morrow, the CTW's generalization from this study, which was later supported by outside studies, was that although repetition was an effective teaching method, repeated exposure "determined instructional effectiveness". "The J commercial" was a part of CTW's promotional film about Sesame Street and was used to demonstrate its teaching style to the press. Sesame Streets animations and live-action films were usually commissioned to outside studios. For example, Misseri Studio in Florence, Italy provided animations for the show for its entire run. Many animations, as well as the show's live-action films and longer segments like Elmo's World were created to accompany