Keith Hayes labeled this clip, “Viki shows definite progress while playing (1.5 years).” He was likely contrasting Viki’s development here with her playful activities shown at age 11 months. What differences do you see between the two clips?

While we don’t know what differences Keith found most interesting, what is most obvious to us is Viki’s continued focus on the task. In the earlier clip Viki moves rapidly from one activity to another -- nothing seems to hold her attention for long. But here she sustains interest in a single task, putting disks on a peg, for a considerable time. Of course, she does stop to taste the blocks, but that just adds a little spice to the festivities.