This is a variation on the “monkey and banana” problem seen in a previous clip. Köhler initially provided boxes for chimpanzees to use in reaching a suspended lure. But other tools were provided as well, including long sticks that were used as clubs to knock down the bananas. Of course, using a long stick as a club is a difficult thing, because any inaccuracies in aiming are amplified over the length of the stick. So they developed another strategy as well: to use sticks as a pole, climbing up quickly before the poorly balanced pole fell over.

Here we see Viki using the same strategy, quickly climbing up a board to reach the lure before it falls over. Köhler's chimps used one more innovative strategy. In one instance, a chimp encouraged Köhler to move closer and closer to the bananas, then quickly climbed his body to reach the bananas!