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1 of 37 • Conditioned reflex activity of the organism. 2 of 37 Pavlov and Classical Conditioning • Ivan Pavlov was a physiologist who won a Nobel Prize for his research on digestion. • His original description of classical conditioning was a by-product of this research. He did not set out to discover classical conditioning. 3 of 37 4 of 37 . 5 of 37 The classic experience of Pavlov is that of the dog, the bell and the salivation to the view of a piece of meat. Whenever we present to the dog a piece of meat, seeing and sniffing it and makes the animal salivate. If we ring a bell, what is the effect on the animal? An orienting reaction. It simply looks around and turns its head to look for where that sound stimulus comes from. If we repeatedly ring the bell, and immediately after show the meat and give it to the dog, after a certain number of times, simply ringing the bell provokes salivation in the animal, preparing its digestive system to receive the meat. The bell becomes a sign of the meat that will come later. The whole body of the animal reacts as if the meat was already present, with salivation, digestive secretions, digestive motricity, etc. An stimulus that has nothing to do with feeding, a mere sound, becomes then capable to induce digestive modifications. 6 of 37 Classical Conditioning • Pavlov noticed that the dogs he used to do his research salivated upon the sight of the lab workers who fed them. – He concluded that this reflex was “psychological” because it was based on the dog’s previous experiences. – Further testing demonstrated that the sight of food produced the same effect as giving the same amount of food to the dog. 7 of 37 • Pavlov started with the unconditioned reflex of salivation to food. He hypothesized that this was an automatic connection. – The dogs had an unconditioned reflex between food and secretion of digestive juices. • A buzzer is called a neutral stimulus because it elicits attention to the sound, but no automatic connection. – The dogs would lift their ears and look around when the buzzer sounded, but no salivation was produced 8 of 37 • He conjectured that animals develop new connections by transferring a response from one stimulus to another. – He hypothesized that if a buzzer always preceded the food, the buzzer would begin to elicit the reflex of salivation. • After a few pairings of the buzzer with the food, the dogs would begin to salivate as soon as the buzzer sounded. 9 of 37 10 of 37 • Terminology 11 of 37 – Unconditioned Stimulus (UCS) An event that consistently and automatically elicits an unconditioned response. – Unconditioned Response (UCR) An action that the unconditioned stimulus automatically elicits. • Terminology 12 of 37 – Conditioned Stimulus (CS) Formerly the neutral stimulus, having been paired with the unconditioned stimulus, elicits the same response. That response depends upon its consistent pairing with the UCR. – Conditioned Response (CR) The response elicited by the conditioned stimulus due to the training. Usually it closely resembles the UCR. 13 of 37 Classical Conditioning Classical conditioning: acquiring a new response (the conditioned response) to a previously neutral stimulus (the conditioned stimulus) that reliably signals the arrival of an unconditioned stimulus. Ivan Pavlov: Russian physiologist who initially was studying digestion; first identified mechanisms of classical conditioning Also known as Pavlovian or Respondent Conditioning 14 of 37 Pavlov’s Experimental Setup 15 of 37 16 of 37 Some Terms • Reflex: a stimulus-response pair in which the stimulus automatically elicits the response • Unconditioned stimulus (UCS): the stimulus in a reflex that automatically elicits a response • Unconditioned response (UCR): the response in a reflex that occurs automatically after the occurrence of the unconditioned stimulus • Example: physician strikes below knee with little hammer (unconditioned stimulus) knee jerk (unconditioned response) 17 of 37 18 of 37 Phases of classical conditioning: Classical conditioning 19 of 37 proceeds through several phases, depending on the time of presentation of the two stimuli. If the conditioned stimulus regularly precedes the unconditioned stimulus, acquisition occurs. If the conditioned stimulus is presented by itself, extinction occurs. A pause after extinction yields a brief spontaneous recovery. 20 of 37 Reflex Action Conditional reflex Voluntary Action (1) Inborn , instinctive Acquired via experience / learning Acquired via thinking / reasoning (2) Cerebrum not involved Cerebrum involved Cerebrum involved (3) Involuntary & unconscious Voluntary & less conscious Voluntary & conscious (4) Fast action Slow action Slow action (5)Same stimulus same response Unrelated stimulus same response Same stimulus different response Components of Classical Conditioning 21 of 37 Unconditioned stimulus: a stimulus that elicits a response without training Conditioned stimulus: A stimulus that elicits a response because it has been repeatedly paired with an unconditioned stimulus Unconditioned response: An innate response elicited by an unconditioned stimulus; usually either a reflex or an emotional response Conditioned response: Term used to refer to a reflex response after learning has occurred to elicit the response by a conditioned stimulus 22 of 37 23 of 37 More on Stimuli & Responses There are two different stimuli: • the unconditioned stimulus, which elicits the response reflexively, without an training [the smell of food] • the conditioned stimulus, which can only elicit the response after training [the sound of the bell] There is only one response [salivation]. What the response is called depends on which stimulus elicited it: • It is the unconditioned response when elicited by the unconditioned stimulus [the smell of food] • It is the conditioned response when elicited by the conditioned stimulus [the sound of the bell] 24 of 37 Principles, continued Stimulus Generalization: A tendency to respond to stimuli that are similar, but not identical, to a conditioned stimulus (e.g., responding to a buzzer or a hammer banging when the conditioning stimulus was a bell) Stimulus Discrimination: The ability to respond differently to various stimuli (e.g., Rudy will respond differently to various bells [alarms, school, timer]) Operant Conditioning (Instrumental Learning) 25 of 37 Operant Conditioning: Learning based on the consequences of responding; we associate responses with their consequences Operant Reinforcer: Any event that follows a response and changes its likelihood of recurring Skinner Box (conditioning chamber) Apparatus designed to study operant conditioning in animals 26 of 37 27 of 37 Timing of Reinforcement Operant reinforcement most effective when given immediately after a correct response Effectiveness of reinforcement is inversely related to time elapsed after correct response occurs 28 of 37 The training of dolphins by rewarding them with food is an example of positive reinforcement operant conditioning. 29 of 37 Types of Conditioning consequence: desirable (appetitive) undesirable (aversive) given positive reinforcement positive punishment taken away negative punishment negative reinforcement yellow increases behavior; blue decreases behavior Comparison: Classical & Operant Conditioning 30 of 37 Comparison: Classical & Operant Conditioning, 2 classical 31 of 37 operant behavior involuntary (reflexive) voluntary (nonreflexive) association of events (CS & UCS) of response & reinforcer expectation that CS signals arrival of UCS that behavior will be reinforced 32 of 37 Types of Reinforcers Primary Reinforcer: Unlearned and natural; satisfies biological needs (e.g., food, water, sex) Secondary Reinforcer: Learned reinforcer (e.g., money, grades, approval, praise) Token Reinforcer: Tangible secondary reinforcer (e.g., money, gold stars, poker chips) Social Reinforcer: Provided by other people (e.g., learned desires for attention and approval) Continuous & Partial Reinforcement 33 of 37 Continuous Reinforcement: A reinforcer follows every correct response Partial Reinforcement: Reinforcers do NOT follow every response Partial Reinforcement Effect: Responses acquired with partial reinforcement are very resistant to extinction 34 of 37 Review: Types of Reinforcers Synaptic theory of creation conditioned reflex 35 of 37 36 of 37 37 of 37 38 of 37 ECG recording in sleep 39 of 37 ECG stages of sleep THE END!