Although the principles of conditioning are very simple, they are less simple in practice. A number of factors affect the effectiveness of conditioning. Timing is important, specifically the time separating the unconditioned and conditioned stimulus. If the sneakers go on too soon before the dog is walked, it will be hard to associate the shoes with the walk.

Relatedly, the reinforcement should closely follow the behavior for the act to be connected with the consequence. This is why news of global warming has had so little effect until recently, although we’ve known about it for decades. The consequences were not immediate. This is also why it is so difficult to instill healthy habits in the young, when the consequences of their self care will not be evident for decades. The schedule of reinforcement also affects learning. Should the behavior be reinforced every time it occurs? What kind of reinforcement makes a behavior most resistant to extinction?