Performance- the behavioural change (or new behaviour) produced by the internal changes brought about by learning: evidence that learning has occurred. Orienting response- any response by which an organism directs appropriate sensory organs (eyes, ears, nose) toward the source of a new stimulus. Habituation- the simplest form of learning: learning not to respond to an unimportant event that happens repeatedly, when stimulus are presented in small groups that are spaced in time, habituation is slower but long term. Involves learning about the conditions that predict that a significant event will occur: sudden sights and sounds can cause an automatic, unlearned reaction. Ivan pavlov discovered a form of learning where the stimulus predicts the occurrence of another stimulus. Classical/pavlovian conditioning- the process by which a response normally drawn by one stimulus (the unconditional stimulus [ucs]) comes to be controlled by another stimulus (the conditional stimulus [cs]) as well.