 Summative research conducted over the years , including two landmark evaluations in 1970 and 1971 , demonstrated that viewing the program had positive effects on young viewers ' learning , school readiness , and social skills . Subsequent studies have replicated these findings , such as the effect of the show in countries outside of the US , several longitudinal studies , the effects of war and natural disasters on young children , and studies about how the show affected viewers ' cognition . As CTW researcher Gerald S. Lesser stated in 1974 , early tests conducted on the show ( both formative and summative ) " suggested that Sesame Street was making strides towards teaching what it had set out to teach " . 
