You want examples? Here they are:
Animal studies:
1. Test whether dogs react more to smell or to their owner's attention to an object: they have to choose between a plate that smells more of food and a plate their owner paid attention to
2. Test whether dogs can follow their owner's gaze: owners call the dogs and then look somewhere and we see whether dogs follow this gaze (look up gaze-following, it's important for learning!)
3. Test whether birds can use tools: give bird a long stick and a box with a peanut inside and see if they can use the stick to get the peanut out
4. Test whether vision can develop in the absence of stimulus: bind kitten's eyes at birth and see if they'll develop perfect vision (they didn't...)