Would you like to go Super Size?

Have you ever stood in front of one of those dual-30″ Cinema Display setups in an Apple Store and wondered whether you’d get a stiff neck working with so much screen real-estate? With desktop display sizes growing quickly, and more and more employers recognising that dual-screen setups can increase productivity, it’s actually becoming a valid question whether there’s a limit past which this trend becomes unreasonable. In certain scientific and military applications, visualisations are already big enough to require physically walking from one part of the display to another.
100 Mpixel display at Calit2, UCSD

At last week’s CHI ’07 conference, two studies from Virgina Tech were presented that fit into this theme. The first one looked into what would happen to users’ performance if a display was so big that it required walking. They tested both a spatial, map-based visualisation and a more abstract grid-based design, at 2560 × 768, 5120 × 1536 and a whopping 10240 × 3072 pixels (about 2.7m × 1.0m or 9′ × 3.5′). The tasks on the larger displays involved more data, and so would be expected to take longer. But it seems that our ability to process visual information scales quite well: people took on average only about three times as long when the visualisation was sixteen times larger (with variation between tasks).

The second study also tested different display sizes (the largest one being the same as in the other study), but with the aim of comparing physical navigation to its “virtual” counterparts, panning and zooming. With the larger displays, participants tended to rely less on virtual navigation, showing that people do in fact prefer moving around or turning their head. This turned out to be the right choice, as it was also more efficient than panning and zooming.

Putting these results together, it would seem that having a larger display always pays off in terms of cognitive efficiency, navigation efficiency and user preference, even if it’s too big to see all at once. Interestingly, both studies found that spatial visualisations benefit more from the extra screen real-estate than non-spatial ones.

Although efficiency is important, it would also be interesting to see a physical ergonomist’s take on the issue. Do extra-large displays hold new risks of work-related injuries, or is the extra movement actually healthier than our traditionally static workstations?