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Visuocognitive design accommodates the alignment of visualization to human cognitive processes. Established theory suggests that 1) recognition is easier than recall [1], 2) spatial visualizations are less abstract than temporal ones [2], and 3) aesthetics induce cognitive ease [3]. These principles, and others, underpin our new audit tool that focusses on design for cognition.Theories of form, function and utility have been known for many decades and are well-known in the field of design, but infovisualization is a relatively new field, as are associated fields such as user-experience (UX), user-centered design and information design. Therefore, generally, design schools focus far more (possibly, exclusively) on teaching form, style, function, sustainability and user-experience than on visuocognition. The same emphasis is found in the design industry. This audit tool has been created to provide heuristic evaluations based on a set of visuocognitive design principles and is, therefore, a valuable contribution.To devise the visuocognitive principles, we conducted a narrative review as a method of approach. The tool is composed of one prerequisite and six principles. ‘Informed Engagement’ is the prerequisite to accurately inform the graphics with ground truth, and to give them substance. The six principles are: 1) clarity, 2) arrangement, 3) cued meaning, 4) intuitive meaning, 5) cognitive fit, and 6) cognitive preference. They are divided into three groups: the first two principles concern appearance, the second two principles concern meaning, and the last two principles concern cognition (Figure 1). The term ‘meaning’ can imply intended meaning by the designer (in a graphic representation), or construed meaning by the user. The novelty of this audit tool is that it fixes ‘meaning’ as the pivotal point between aesthetic visual display and mental cognition, with the aim to align construed meaning with intended meaning and achieve fluent cognition.

International audience; The notion of multi-layer networks introduces a general framework and common vocabulary for existing ideas in complex network theory. In doing so, it is possible to understand and compare these dierent ideas in a new and more fruitful manner. However, to make this operationalizable to the visualization and visual analytics community, we need more clarity. For example: What is a layer? What are the semantics of interlayer edges, and specifically, identity links between layers? Can dierent multilayered networks be expressed or implemented in the same way? And vice versa, can one multilayered network be expressed or implemented in dierent ways?

Experiments that require the use of human participants are time consuming and costly: it is important to get the process right the first time. Planning and preparation are key to success. This practical book takes the human-computer interaction researcher through the complete experimental process, from identifying a research question to designing and conducting an experiment, and then to analysing and reporting the results. The advice offered in this book draws on the author's twenty years of experience running experiments. In describing general concepts of experimental design and analysis she refers to numerous worked examples that address the very real practicalities and problems of conducting an experiment, such as managing participants, getting ethical approval, pre-empting criticism, choosing a statistical method and dealing with unexpected events.

International audience; Metabolic networks have been drawn manually for many years, and over time have developed representational conventions that make them familiar to biologists. With increasing current biological discoveries, these networks need to be frequently updated and modified, and automatic visualization algorithms are thus becoming a necessity. Many existing automatic graph layout algorithms exist, and it is not known whether such generic algorithms are sufficiently useful for biologists, or whether algorithms that specifically consider the existing representational conventions are necessary. No prior task efficiency evaluation studies have been performed on biological network visualizations. This paper reports on an experiment comparing the task efficiency of biologically relevant motif-search tasks using three layouts, two of which were produced using existing generic graph layout algorithms (Force Directed, Hierarchical), and one which was specifically designed to take existing metabolic representation conventions into account (MetaViz). Despite the search task favouring the easy identification of node connectivity in the Force Directed layout, the results showed no efficiency difference between Force Directed and MetaViz. We conclude that embodying the representational conventions in an automatic algorithm is not an impediment to task efficiency, and that some minor improvements to MetaViz would enhance its usefulness for biologists even further.

The algorithm of Tutte for constructing convex planar straight-line drawings and the algorithm of Floater and Gotsman for constructing planar straight-line morphs are among the most popular graph drawing algorithms. Surprisingly, little is known about the resolution of the drawings they produce. In this paper, focusing on maximal plane graphs, we prove tight bounds on the resolution of the planar straight-line drawings produced by Floater’s algorithm, which is a broad generalization of Tutte’s algorithm. Further, we use such a result to prove a lower bound on the resolution of the drawings of maximal plane graphs produced by Floater and Gotsman’s morphing algorithm. Finally, we show that such an algorithm might produce drawings with exponentially-small resolution, even when morphing drawings with polynomial resolution.