Observing changes on a single array element in Ember

Is it possible to observe changes on a single array element in Ember?

[] and @each properties can be used to observe changes on all array elements, but what if I am only interested in one element and don't want updates for the rest? Especially if the rest of the array is large and changing often.

I would have hoped that observing things.[0].name would work, am I missing something?

  atEachNameChanged: Ember.observer('things.@each.name', function() {
    this.get('messages').pushObject('@each triggered');
  }),

  atIndexedNameChanged: Ember.observer('things.[0].name', function() {
    this.get('messages').pushObject('[0] triggered');
  }),

  bracketNameChanged: Ember.observer('things.[].name', function() {
    this.get('messages').pushObject('[] triggered');
  }),

Twiddle code sample