The amount varies according to design, content, motivation, etc. True over hundreds of studies. Their attitudes actually improve. If students use computers for learning, they lose their positive attitude toward computers. If students use computers for learning, they gain interest in the subjects they are studying.
Interest stays the same.
Positive effects for achievement were found for all major subject areas, in preschool through higher education. The lack of high touch from human teachers in drill and kill software leads to a decline in self-concept and attitudes toward learning. Numerous studies have demonstrated that tech is particularly valuable in improving student writing. When schools increase their tech attendance increases and dropout rates increase. This is for teachers as well as for students.