Short Delay: Element Movement Long Delay: Group Movement
In the first example, there is not enough time for our brain to link together the point to point comparisons and thus it is "Element Movement" that is perceived, (since this is less work for the brain).. In the second example though, when the delay is longer, it is easier for the brain to carry out the detailed comparisons of the alternating diagrams. There is enough time for the brain to associate all three dots to their counterparts in the second frame, so our brains make the comparison. I noticed that the transition from element movement to group movement occured at approximately 90/100 of a second (but this is only for this particular example).
Duration: 110/100 second
Duration: 85/100 second
Duration: 35/100 second