I saw something like this on NATGEO. Dogs pay attention to humans with more intensity compared to any other animal.
They did a similar test with a chimp. With the chimp behind a glass with three small openings for it's hands, a woman put down three cups in front of each opening. She then placed a small piece of food under one cup and moved the cups around. The chimp was watching her the entire time. So when she was finished, he had picked the cup where the food was under.
Next, she covered the glass window up and placed the food under another cup. When she moved the cover, the chimp automatically picked the same cup. She then pointed to the cup hiding the food. However, the chimp was confused and continued to point at the same cup it picked before.
Now, she did the same test with the dog. When it came to following the cups, the chimp proved superior. However, when the lady pointed at the cup hiding the treat, the dog picked that cup with over 90% accuracy!
Why? Because chimps are not domesticated animals and they have no real reason to pay close attention to our gestures, facial expressions, etc. Dogs do. Dogs evolved to understand our emotions, body language and even facial expressions. The dog knew by paying attention to the lady, she would eventually show it where the food was.
PB