Classical Conditioning. Classical and Operant Conditioning. Basic effect. Classical Conditioning

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1 Classical Conditioning Classical and Operant Conditioning January 16, 2001 Reminder of Basic Effect What makes for effective conditioning? How does classical conditioning work? Classical Conditioning Reflex-basic unit of behavior Ring a bell and give a sour ball soon you will salivate to the sound of the bell = conditioned reflex. Basic effect If Unconditioned Stimulus Unconditioned Response (meat powder) (salivation) then pair Conditioned Stimulus with the Unconditioned Stimulus (bell) (meat powder) then eventually Conditioned Stimulus Conditioned Response (bell) (salivation) Who didn t know this already? Who didn t know this? If Unconditioned Stimulus Unconditioned Response (smell of food) (approach) then pair Conditioned Stimulus with the Unconditioned Stimulus (sound of can opener) (smell of food) then eventually Conditioned Stimulus Conditioned Response (sound of can opener) (approach) 1

2 Measurement You can t answer questions effectively without an experimental method It s not enough to say cat comes How many times must it hear the can opener? What if sometimes I open a can of soup? How quickly will the cat come? Can any stimulus be associated with any response? WHY does the cat come? Many questions you could ask What makes an effective CS and US? How might classical conditioning work? What makes effective CS & US Belongingness Taste->vomiting, sight->shock Effect observed in humans, too. Fear conditioning to snakes/spiders vs. flowers/mushrooms (dv = GSR) What makes effective CS & US Novelty Bell alone, then bell food Bell associated w/ background Bell associated w/ no food Food alone, then bell food How does CC work? CC can be thought of as adding predictability to the animal s environment. Learning that one stimulus is conditional on the other. If one stimulus is not conditional on the other, you won t get learning. How does CC work? Importance of one stimulus being conditional on another. If you present CS and US randomly, you don t get learning. Animals should ignore stimuli that don t have predictive value. 2

3 Predictive value--blocking Group 1: Tone Shock Training 1 Training 2 Test Tone Light Shock Light Shock Learning = bad The Point of Blocking The animal only learns what light means if light carries new predictive information Group 2: x Light Shock Light Shock Learning = good Rigor allows prediction Note how different this enterprise is than the casual observation of your cat. Final phenomenon-- secondary conditioning What do you think would happen if you taught a dog Light Food, and then taught it Bell Light, Answer How does secondary conditioning apply here? The dog would learn it, and would eventually salivate to bell. Question... 3

4 US = food, UR = approach, hovering CS = arm motions, CR = approach, hovering Secondary CS= looking up, CR = approach, hovering What s happening, and what should the birds do? What s happening: removal of secondary CS What should the birds do?: extinction of CR Moments later, birds are leaving Application to humans? Application to humans? Food anticipations--salivation Food aversions Drug tolerance & addiction 4

5 Drug Addiction and Overdose CC plays a role in deaths caused by drug overdoses Person who usually takes a drug in a particular setting develops a CR to that place. Drug Big Response (e.g. hypothermia) and body tries to return to homeostasis Drug Addiction and Overdose Drug Body attempts to counteract (raise body temp.) US UR Setting (e.g. bathroom) Drug CS US Bathroom Body attempts to counteract drug CS CR What happens if the drug is taken in a different room? Drug Addiction and Overdose CR does not occur (user s body does not try to counteract drug) and the user can not tolerate the higher dose. Drug Addiction Craving for drug is an attempt to get back to homeostasis: Craving is caused by Conditioned Stimuli e.g.: handling money seeing a friend take drug talking about drugs being in specific setting Operant Conditioning Operant Conditioning Conditioned reflexes couldn t account for all behavior Active response future change in response depending on consequences. 5

6 Operant Conditioning In classical conditioning, the presence of one stimulus (e.g. meat powder) is conditional on the presence of another stimulus (e.g., a bell) What else can an animal learn, besides the relationship of two stimuli? Operant Conditioning It is also possible for the animal to generate a response and for that response to have consequences: e.g., act cute, you get pet What makes OC effective? Temporal contingency Schedule of reinforcement Belongingness Temporal Contingency The delay between the animal s act that you are reinforcing, and the reinforcer. Immediate is more effective than delayed for animals. Humans can learn effectively after delayed reinforcement. Operant Conditioning Relies on reinforcement: The process by which consequences lead to an increase in the likelihood that the response will occur again. Reinforcement Positive Reinforcement: desired event is presented after a response. example: food when animal presses bar Negative Reinforcement: removal of an unpleasant event example: removal of shock when animal presses bar. 6

7 Schedules of Reinforcement Fixed ratio number Variable ratio number Fixed interval time Variable interval time Fixed ratio Reinforcement is given after a fixed ratio of responses. Number of Responses Example: factory piecework Steady response Easy to extinguish Time Variable ratio Reinforcement is given after a variable ratio of responses. Number of Responses Example: slot machine Rapid response Hard to extinguish Fixed interval Reinforcement is given for a response emitted after a fixed interval of time. Number of Responses Example: studying for exams Little response until just before reinforcement: then rapid response Fairly easy to extinguish Time Time Variable interval Reinforcement is given for a response after a variable amount of time. Number of Responses Example: checking mailbox (sort of) Steady response Hard to extinguish Operant conditioning--what makes it effective? Temporal contingency Schedule of reinforcement ** Belongingness Time 7

8 Belongingness Thorndike: Cat and puzzle box. Pressing lever led to door opening Not yawning or scratching Motivational state can also influence; a hungry animal does more for foodseeking behaviors... Applications Animal training Superstition Teaching Machines Token Economies Animal Training Revolutionized animal training Shaping Importance of temporal contingency Exclusive use of positive reinforcement Complexity of behaviors when these rules are followed. Superstition Skinner left pigeons alone, reinforced every 15 seconds. Reported that they developed superstitious behavior, each bird having a different behavior. Pigeons appeared to believe that they were making the food appear Temporal contingency--birds were doing something when the food appeared... Superstition Superstitious behavior: depends on accidental association between action and consequence Teaching Apply operant conditioning principles to learning Make sure student doesn t make mistakes; guide behavior via successive approximations Review frequently Little enthusiasm. Teachers don t like it and students are bored. 8

9 Behavior Modification Token economies Secondary reinforcement dehumanizing? Operant and Classical CC: Neutral stimulus comes to have meaning OC: Neutral response comes to have meaning Are they really different? 9