Dr. Carla Spinillo, is lecturer and researcher at The Federal University of Pernambuco, Brazil. Her PhD Thesis "An analytical approach to procedural pictorial sequences" has been devoted to the study of this field that only recently has begun receiving the attention it deserves. Carla has been kind enough to contribute with the following introductory article to Inf@Vis!.

The use of pictures to convey instructions has been widely employed in a variety of user’s documents, such as leaflets and manuals. It is intended to facilitate communication, as pictures represent better than words certain information, such as relative size and connection of pieces (e.g. Bieger & Glock, 1986; Weidenman, 1994; Wildbur & Burke, 1998; Mijksenaar & Westendorp, 1999. See the references).

Pictures are also an important means of communication when the instructions or procedures are addressed to an international audience or to an audience with a low level of literacy. 

This paper briefly discusses some features and relationships that characterise this kind of visual instruction.

The representation of procedures through pictures (alone or together with texts) is referred to as a procedural pictorial sequence – PPS – (Spinillo & Dyson, 2000; Spinillo, 2000). The analysis of such sequences is a complex issue, due to the versatility of their graphic presentation, which involves a wide range of aspects and relationships. 

Three main relationships are identified in procedural pictorial sequences:  Syntagmatic, that refers to the sequential relation between the steps of a procedure, which cannot vary without affecting the message of the PPS, i.e. step A is followed by step B and so forth Paradigmatic, when the graphic presentation of a procedure may vary (e.g. horizontal, vertical) without jeopardising the PPS’ message  Hierarchical. when the steps of a procedure are  in a part-whole relation, in which there are steps and sub-steps in PPSs  Regarding the number of pictures, we can distinguish two types  Synoptic sequence when a procedural pictorial sequence present a single picture. In this case the notion of sequencing is implicit, that is to say, the succession of events occurs within a picture. See Figure 1. Discrete sequence if the procedure is represented with a series of pictures. In a discrete sequence the notion of sequencing occurs in between the pictures. See Figure 2. The content of PPSs can be procedural and non-procedural.

Figure 1. A Synoptic Sequence.  From Mijksenaar, P. and Westendorp, P. Ó 1999.  Open here: the art of instructional design. Thames and Hudson, London  (click on the image to zoom it) Figure 2. a Discrete Sequence From Mijksenaar, P. and Westendorp, P. Ó 1999.   Open here: the art of instructional design. Thames and Hudson, London  (click on the image to zoom it)

• Procedural. The completeness of the procedural content representation is a prime decision in the design process, since the omission or the provision of too many steps may jeopardise the task performance (e.g. Chapanis, 1965; Carroll & Van der Meij, 1998). 
  
  
• Non-procedural content has the purposes of introduction (e.g. titles), warning (do not smoke) and supplement (e.g. tips). Content with the purposes of warning and introduction can be fundamental to carrying out the procedure as well as helping readers decide whether they want to perform the procedure or not (Farkas, 1998).

Once given the basic definitions, in the next issue we’ll speak about the visual organisation and the design guidelines applicable to pictorial instructions.

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