Is Beautiful Usable, or Is It the Other Way Around?
A group of researchers from two European universities have evaluated if “what is beautiful is usable” is true in software, and they have concluded that “what is usable is beautiful.”
The paper Is Beautiful Really Usable? Toward Understanding the Relation Between Usability, Aesthetics, and Affect in HCI (PDF) signed by Alexandre N. Tuch, Sandra P. Roth, Kasper Hornbaek, Klaus Opwis, Javier A. Bargas-Avila from the University of Basel, Switzerland, and University of Copenhagen, Denmark, analyzes the relationship between usability and aesthetics, trying to find evidence for the known collocation "what is beautiful is usable".
The authors start by reviewing existing studies, noting that previous results are contradictory and have not established a clear relationship between aesthetics and usability:
The directions of the aesthetics-usability relation are currently unclear. To our knowledge, only five experimental studies provide reliable information on the directions of the relation. Because their findings are mixed, it is not possible to draw a clear conclusion. An explanation for the mixed result pattern might be the different ways of experimental manipulation and assessment of the dependent measures between the studies. A key difficulty for experimental studies is the systematic and independent manipulation of aesthetics and usability. This is crucial for drawing causative conclusions about the aesthetics-usability relation. In some studies, aesthetics and usability appear to be confounded. For instance, manipulating the aesthetics factor through changing or moving certain interface-elements involves the risk of unintentionally changing the interface's usability (Tractinsky et al., 2000). Manipulating usability may have a similar confounding effect on aesthetics.
After critiquing the results of previous researches, the authors decided to perform an experiment meant to more accurately measure the relationship between aesthetics and usability. They set up four variants of the same online shop, two with high and low aesthetics and two with high and low usability, following established known rules for creating such websites. The usable and non-usable versions of the shop had the same look, contained the same items, and had the same menu width and breath. Only item/menu labels and product categorization were different. 80 participants were invited to evaluate the shops, then perform several operations, ending with another evaluation.
The conclusion of the study was: aesthetics does not affect perceived usability, but degraded usability negatively affects perceived aesthetics. In other words, usability is more important than beauty. The graphs below show how classical aesthetics varied during the experiment:
The authors concluded that "what is usable is beautiful":
Most existing studies found an effect (or at least a trend) of interface-aesthetics on perceived usability. Two studies (Ben-Bassat et al.,2006; Lee and Koubek, 2010) also found an interface-usability effect on perceived aesthetics alongside the interface-aesthetics effect, but the effect was less pronounced. Our results show that Tractinsky's notion ("what is beautiful is usable") can be reversed to a "what is usable is beautiful" effect under certain circumstances.Second, aesthetic perception of the interface changes significantly over time: both classical aesthetics and HQI [Hedonic Quality Identification] were affected by the experienced usability.
The paper (PDF) presents in detail the experiment performed, how perceived aesthetics and usability was measured, how results were processed, and how the authors reached their conclusion.
...and they have concluded that “what is usable is beautiful.”
"what is usable is beautiful" is true as usability causes the user
(and hopefully the designer) to refine his aesthetic judgment.
One could say that aesthetics is to design what morality is to social life:
a set of heuristics that helps make it better, for the users or the participants,
and is refined according to experience teachings (or natural selection for those
that don't want to learn).