Research examined the learning effects that encouraging Israeli mothers to co-observe Sesame Street with their five-year-olds had. The mechanism which mediated such effects was also investigated. A total of 93 kindergarten children, drawn about equally from lower and middle class families, was divided between mothers' encouraged and non-encouraged conditions. Encouraging mothers had a profound effect on the amount the lower socio-economic status (SES) children watched the show and particularly on their enjoyment of the program. This in turn had an effect on their learning, attenuating significantly the original SES differences. It was concluded that encouragement of mothers to co-observe television had significant effects on the development of specific skills, mediated by increased positive affect on the lower SES, but not in middle class children. Findings were interpreted as suggesting a decrease in experienced uncertainty and hence increased pleasantness as a function of mothers' active participation in viewing the program. (Author)