Study of computer-assisted learning examined the learning of "blissymbols" by children. blissymbols are pictographs (think of egyptian hieroglyphs) that are sometimes used to learning-impaired children communicate. the researcher designed two computer lessons that taught the same content using the same examples. one lesson required the children to interact with the material, while in the other the children controlled only the pace of the lesson. call these two styles "active" and "passive", respectively. children were assigned at random to active and passive groups. after the lesson, the computer presented a quiz that asked the children to identify 56 blissymbols. what type of study is this?