Shot of dog on test table, tube coming out of his face. Closer shot of front of dog as narrator speaks. Shot of metronome being put on table, narrator says that the sound is converted into a signal for food as dog eats from food bowl. CU dogs face. CU of metronome. Shot of food being switched, dog eating. Shot of dog eating, metronome by its head. Screen goes black, cuts to shot of diagram of dogs face and metronome in corner. Narrator talks about how two nerve sensors are triggered by metronome. Camera zooms in on nerves in brain. Zooms out as narrator describes how the metronome stimulates saliva gland. Cut to shot of birds in tree. Narrator talks about the rooks.