Seductive details constitute interesting but irrelevant information that are not necessary to achieve the instructional objective. The seductive detail effect occurs when people learn more deeply from instructional messages that exclude rather than include these details. There are various explanations of this effect, for example that adding information which does not aid learning but does take up mental resources can cause 'cognitive overload' which hinders the learning of relevant information.
In a review of 39 experimental effects in the form of text passages, illustrations and other kinds of seductive details, Rey (2012) reveals a significant seductive detail effect with small to medium (retention performance) and medium (transfer performance) effects. Furthermore, empirical evidence for moderating effects and various explanations of the seductive detail effect are reviewed. Empirical data supports, but also calls into question, each of the four explanations. The review concludes by discussing the theoretical and practical implications, as well as the limitations and future directions of this research.
Rey, G. D. (2012). A review of research and a meta-analysis of the seductive detail effect. Educational Research Review, 7(3), 216-237.