Attentional tracking and spatial relations

In the movie bellow, while looking at the cross, try to follow with attention the object that is red at the start. Is that object the same object that turns red at the end of the display?

The task is quite easy. But what happens if we increase the speed?

You can see that the task gets much harder. We used displays similar to these ones and found that most people cannot follow with attention an object when exceeds about 1.4 revolutions per second.

Speeds faster than this ‘magic’ speed give us the opportunity to test how is the perception of objects when attention cannot be continuously attached to a single object. We found an impossibility to perceive spatial relationships.

In the movie above, it is quite easy to perceive that every green object is chasing the blue object, that at the same time is chasing the red, that is chasing the green... But what occurs if we speed up the display?

Probably you still can perceive that there are green, red and blue objects. That means that for fast speeds, although you cannot follow objects with attention, access to the perception of colours is still possible.

But now try to find which is the ‘chasing order’ of colours. Did you notice that actually now green is chasing red instead of blue? We found that above 1.4 revolutions per second, people cannot tell which is the chasing order. This suggests that attentional tracking is necessary to perceive whether two objects are near to each other.

Perceiving spatial relationships via attentional tracking and shifting. Holcombe, A.O., Linares, D., Vaziri-Pashkam, M. Current Biology, in press. (article in The Conversation)