Do Radial Menus have an implicit hierarchy?

Question

I've been designing radial menus (also known as pie menus, or contextual menus) for some time. Mostly for the video game industry. I've had a lot of success with them, and I find them helpful for presenting players with primary, secondary, and complimentary actions based on a single click.

But I've made a lot of assumptions with these menus, and I wonder if there is much research out there on the topic of hierarchy. For a menu with 4 choices, I've made the assumption that there is an order where the user (player) would look. Here is the order I've assumed:

1 Up

2 Down

3 Right

4 Left

Therefore, I've placed my actions appropriately:

• Up - Primary
• Down - Secondary
• Right - Tertiary
• Left - Least important

Do any of you know of any research to support/challenge this assumption? Is this just a heuristic call?

Thank you for the help!

Answer 1

No. Radial menus do not express hierarchy, and no menu item gets parsed first (the two are not the same, incidentally).

Research into radials (like, say, http://www.donhopkins.com/drupal/node/100 ) shows that seek time for any arbitrary element is generally consistent regardless of position. This isn't consistent with the premise that radial items are read in an order and that this order affects selection.

Another thing: don't assume that just because a user looks at certain elements before others, those elements enjoy primacy. There is a big, big difference between looking at something and parsing it. For instance, eye tracking studies show that in linear menus, users look at the first item, then the last, and then the rest. This implies that seek times on the last element should be very fast (second only to seek times on element 1) but they're actually usually the worst - because when the user initially scanned the first and last item, he did it to identify the bounds of the object, not identify the elements themselves.