This is a conditioning principle in which an organism is reinforced every single
time that organism provides the appropriate response. For example, you
might present a food pellet every time the rat presses the lever. One of the
biggest dangers when using this type of reinforcement is saturation (the
organism basically gets full - you keep feeding it and it no longer wants the
reinforcement because it is stuffed), so the idea that giving reinforcement all
the time is the best way to teach/learn is not necessarily true.