very hard to explain in detail.....
here's my opinion :

a)needs and wants>action to fulfill needs and wants>assessment of the result of action>return to step 2 if needs and wants not fulfilled and action is changed......if needs and wants is fulfilled, action is "reinforced" or remembered.

b)conditioning
for details : http://en.wikipedia.org/wiki/Classical_conditioning
generally the organism learn something(in this case relate bell to food) when repeated "reward"(fulfillment of needs or wants)


c) reinforcement
http://en.wikipedia.org/wiki/Reinforcement


additional reading material : http://en.wikipedia.org/wiki/Operant_conditioning