Studies on the effects of adjunct aids (examples, pictures, inserted questions) in higher education textbooks have generated mixed results. These mixed results have been explained by referring to the lack of (adequate) use of the aids (e.g., André, 1979; Peeck 1993). In this study, the use of aids is further studied by exploring whether students' general and specific instructional conceptions affect their use or whether features of the aids themselves are more influential. Instructional conceptions are ideas of students about the functionality for learning of instruction in general and of specific interventions in particular (Lowyck, Elen, & Clarebout, in press). The study was based on the assumption that instructional conceptions affect the use of adjunct aids and, hence, might moderate learning outcomes. As an alternative hypothesis, it was proposed that the sheer number of adjunct aids or the type of adjunct aids rather than the conceptions of students affects their use.After assessing prior knowledge and instructional conceptions, 255 participants studied a 6446 word passage with different numbers (0 or 5) of three types adjunct aids on a computer screen. The use of the adjunct aids was monitored. (M)ANOVA analyses show no impact of either general or specific instructional conceptions. Whether prior to the confrontation with the aids students conceive an aid as more or less functional, has no relationship with the actual use of that aid. Even worse, the only effect found, shows that those who regard figures to be less functional use them more. In other words, students' answers on the different scales of the instructional conceptions questionnaire have no predictive value as to the use of adjunct aids.In contrast to instructional conceptions, the number and type of aids inserted, however, seems to affect their use. Results seem to suggest that, in order to promote the use of the aids and the time spent on them, a reasonable number of aids is to be inserted. While it is to be explored empirically what a reasonable number is, this study suggest that for a text of about 7.000 words inserting more than ten aids does not help to increase their use. Furthermore, results show that -when available- figures are used more than either examples or questions. Further research will have to investigate whether this is a 'perceived ease'-effect or a modality effect. The first effect would claim that students assess the 'ease' of spending time with a particular aid or intervention and spend most time with the aids that are regarded to be most easy. The modality effect would claim that students prefer to access those interventions whose format or 'modality' is most different from the remainder of the information.ReferencesAndré, T. (1979). Does answering higher level questions while reading facilitate productive learning? Review of Educational Research, 49, 280-318Lowyck, J., Elen, J., & Clarebout, G. (in press). Instructional conceptions: a prospective analysis. International Journal of Educational Research.Peeck, J. (1993). Increasing picture effects in learning from illustrated text. Learning and instruction, 3, 227- 238.