I was upstairs getting something to drink and saw some cold groundbeef in the fridge. I got a bunch, ripped it into little dime-sized balls and started it dropping from the upstairs deck, two floors above them, down to the bottom deck.
At first they'd just hear/feel the thump and look around confused. Then they'd sniff a bit, wander around, and one of them would find it.
After 4 or so, they figured it out... thump meant meat, and they'd localize and eat it almost as soon as it hit ground. Incredibly fast reactions.
Then they started competing and it almost got a little nasty, so I decided to drop two at once, aiming one per dog. I yelled both their names, they looked up, I adjusted, then dropped....
The two pieces of meat hit the ground at the same time, one in front of each dog, and both dogs heard the dual-thump, flinched to jump, but neither moved: they were both confused by the double thump and couldn't localize it. Each had a piece of meat right in front of them, but it took them both 5 long seconds before they thought to resort to their old slow sniffing technique... then in parallel they both sniffed the same ways, and both ate their meat right at the same time.