Data Visualisation forms should be constrained by their function. I explain the background to this design principle and how to select the right form.
The maxim “Form follows function” was first stated in 1739 by American Sculptor Horatio Greenough and later became a battle cry for the architect Louis Sullivan roughly 100 years ago and was restated by Frank Lloyd Wright as “Form and Function are one”.
Along with “Less is More” it has been hugely influential to designers ever since, either being taken literally or wholeheartedly rejected. Today, the implication in “form follows function” is that as long as the functional requirements are satisfied form will follow and seem pleasing. However, this is not the original intention, Sullivan was pointing out for example that in nature the form of a living entity expresses its inner life and essence (the function), they are so intrinsically related that they are one.
What Sullivan actually said was that “Form ever follows function” and he was actually describing natural objects where the shape expresses the inner life or essence of the animal, in this way they are intrinsically linked.
According to Victor Papanek, respected industrial designer, “this statement has contributed to a seeming divorce between that which works well and that which is beautiful”. He goes on to say that “The concept that what works well will of necessity look well has been the lame excuse for all the sterile, operating-room-like furniture and implements of the 1930’s and 1940’s”. He was specifically talking about dining room tables, which although highly functional looked like operating tables. Nothing about the table said “Come dine off me” or spend some quality social time around me. In his experience “the most often heard, the most understandable, yet mixed up question” he hears from designers is “Should I design it to be functional or to be aesthetically pleasing”. In other words “Do you want it to work or to look good?” “Barricades are erected between what are really just two of the many aspects of creating a functioning design”.
But we should ask ourselves the question – How relevant is “Form follows function” to data viz and other technology design? Not very because there is no hard connection between the objects form and its function. If we take an iPhone (which is packed with microelectronics) there is no clue as to what the button does. The connection between form and function must be learned.
One of the interesting characteristics of early UI design, that helped us learn this connection between technological function and form, is the use of common widgets or metaphors that bridged the user experience back to its mechanical predecessor.
Is this not why we call our data vizs “Dashboards” as it is a metaphor for a control device? And also the reason for the prevalence of gauges and various other meter type visual components.
But now our users are more sophisticated via the consumerisation both of gadgets and BI. When we turn to interactive data vizs we should certainly honour this sophistication and use features and charts that they are familiar with e.g. Faceted Search, accordion menu controls etc.
So it is true that function does not necessarily determine form. But it is also true that “the form of a technological object must depend on the tasks it should help with”. So a more appropriate take on this is provided by Alberto Cairo who put it succinctly that “The form should be constrained by the function” i.e. having a detailed understanding of the tool’s function is critical to picking the right form. Whilst there may be more than one way to encode the data properly, so that the users can obtain meaning from it, the data cannot adopt any form. Choosing visual shapes to encode information should not be based on aesthetics and personal taste alone.