EFFETS DU FORMAT DE PRÉSENTATION DES INSTRUCTIONS SUR L'APPRENTISSAGE DE PROCÉDURES À L'AIDE DE DOCUMENTS TECHNIQUES

In order to improve the design of procedural documents, technical writers have to take into account how users process information. In this paper, we propose a model describing how users deal with technical documents when faced with a new device – in this case a domestic appliance – and we specify the mental processes involved in this interaction. When a user reads a series of instructions and executes them, he/she moves from the perception of a linguistic and/or a pictorial presentation to the realisation of (an) action (s). In order to accomplish such a transformation, people may selectively use the following sources of information either jointly or sequentially : the equipment, the characteristics of the document, and their prior knowledge. Cognitive processes involved in this processing include a) activating and/or maintaining the goal in working memory b) encoding the instructions c) encoding the characteristics of the device d) elaborating an integrated representation of all these sources and elaborating an action plan, and e) executing the action. In addition, this model implies that users are able f) to control the procedure and to compare, within each step of the procedure, the state of the device to the initial goal, and g) to regulate the above processes until the initial goal is achieved. Based on this model, an experiment was run to explore how people read, understand and execute instructions usually shown in technical documents (text andlor picture formats). One hundred twenty adults were asked to realise several tasks using instructions. Three kinds of instructions formats (text-only ; picture-only ; text-and-picture) were crossed over two conditions of presentation (compact vs. step by step). Four principal measurements were made : reading time (for the instructions) ; inspection time (for the equipment) ; execution time ; and total task time (time to carry out the instructions from initial reading to the end of the task). The results showed that : 1 / the reading time of the instructions was shortest with the picture-only format ; 2 I the inspection time of the appliance was longest with the text-onlyformat ; 3 / the execution phase of the task was shortest with the text-and-picture format ; and 4 / the total time to carry out the tasks was longest with the text-only format. These results suggest that pictures facilitate processings. Pictures allow faster encoding and facilitate the integration of information from different sources. The fin