A Stimulus is any action from our environment (that registers in our senses) that causes us to respond in a certain way. An unconditioned stimulus usually creates a response beyond our control. Thus, if we are sitting in a quiet place, a sudden loud noise will startle us. Touching a hot object may cause us to jump back quickly. An unpleasant odor may get us to wrinkle up our nose. A conditioned stimulus is one we must be trained to respond to. Pavlov’s dogs were conditioned to salivate when a bell rang. You are conditioned to complain immediately about homework, even if it might have some benefit for you.
