 CTW 's early studies with the distractor found that children learned more when they watched the program carefully , or when they participated by singing or talking along . In re @-@ tests four weeks later , it found that children retained most of what they learned . After the first three weeks , or 15 episodes , viewers and non @-@ viewers were compared ; few differences in learning were found . When both groups were tested after six weeks more differences began to appear , with viewers scoring higher than non @-@ viewers . A two @-@ season CTW study published in 1995 found a " significant increase " in difficulty in remembering the letter and number of the day . Based on the multiple @-@ intelligence theory , producers began to cluster Sesame Street 's short films , animations , and inserts around a single topic rather than sprinkling several topics throughout a single episode . 
