A COST-BENEFIT-ANALYSIS MODEL TO DESCRIBE THE PERCEPTION AND USE OF ACTIVITIES IN SELF-INSTRUCTIONAL TEXTS

The results of a qualitative study, that explored students' perception and use of Activities in self-instructional texts, are described, ill ustrated and analysed. The emergent constructs, identified by means of interview questionnaire and self-recorded audio-tape, are interpreted in the context of a Cost Benefit Analysis Model. The findings challen ge the dominant model of Mathemagenic Devices and of experimental rese arch into adjunct questions; it offers a methodology and frame-work by which students' perceptions and use of Activities can be explored.