classical conditioning and discrimination


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classical conditioning and discrimination

  2. 2. CLASSICAL CONDITIONING DEFINITION : Classical conditioning is defined as a conditioned response to a neutral stimulus after having been paired repeatedly with an unconditioned stimulus .This response is involuntary . Pavlov and Classical Conditioning • Ivan Pavlov organized and directed research in physiology at the Institute of Experimental Medicine in St. Petersburg, Russia, from 1891 until his death 45 years later. • The Institute of Experimental Medicine is where he conducted his classic experiments on the physiology of digestion, which won him a Nobel Prize in 1904.
  3. 3. Copyright © Allyn & Bacon 2006 Classical Conditioning The Process of Classical Conditioning • Reflex: an involuntary response to a particular stimulus, such as the eye blink response to a puff of air or salivation when food is placed in the mouth Two types of reflexes: • Conditioned reflexes (learned): a learned reflex rather than a naturally occurring one. • Acquired in life not transmitted through genes. • It can be established or abolished . Unconditioned reflexes (unlearned): inborn, automatic, unlearned response to a particular stimulus. naturally occurring response to the unconditioned stimulus  salivation when food is in the mouth
  4. 4. Copyright © Allyn & Bacon 2006 Classical Conditioning The Conditioned and Unconditioned Stimulus • conditioned stimulus (CS): any stimulus , such as ringing bell, that with prior learning will elicit, or bring forth, an conditioned response. • Unconditioned stimulus (US): any stimulus, such as food, that without prior learning will automatically elicit, or bring forth, an unconditioned response. stimulus that unconditionally--automatically and naturally-- triggers a response
  5. 5. BEFORE CONDITIONING • In order to have classical or respondent conditioning, there must exist a stimulus that will automatically or reflexively elicit a specific response. This stimulus is called the Unconditioned Stimulus or UCS because there is no learning involved in connecting the stimulus and response
  6. 6. DURING CONDITIONING During conditioning, the neutral stimulus will first be presented followed by the unconditioned stimulus. Over time, the learner will develop an association between these two stimuli (i.e., will learn to make a connection between the two stimuli)
  7. 7. AFTER CONDITIONING After conditioning, the previously neutral or orienting stimulus will elicit the response previously only elicited by the unconditioned stimulus. The stimulus is now called conditioned stimulus because it will now elicit a different Response as a result of conditioning or learning. The response is now called a conditioned response because it is elicited by a stimulus as a result of learning.
  8. 8. Copyright © Allyn & Bacon 2006 CLASSICAL CONDITIONING John Watson and Emotional Conditioning • John Watson and his assistant, Rosalie Rayner, conducted a study to prove that fear could be classically conditioned. • The subject of the study, known as Little Albert, was a healthy and emotionally stable 11-month-old infant. • Little Albert showed no fear except of the loud noise Watson made by striking a hammer against a steel bar near Albert’s head.
  9. 9. Copyright © Allyn & Bacon 2006 Classical Conditioning John Watson and Emotional Conditioning • Rayner presented Little Albert with a white rat; as Albert reached for the rat, Watson struck the steel bar with a hammer. • This procedure was repeated several times. • This procedure caused Albert to begin to cry at the sight of a rat.
  10. 10. Copyright © Allyn & Bacon 2006 Classical Conditioning John Watson and Emotional Conditioning • Watson also had ideas for removing fears and laid the groundwork for some behavior therapies used today.  Watson and a colleague, Mary Cover Jones, found 3-year-old Peter, who was afraid of rabbits, and tried Watson's fear-removal techniques on him. Peter was put in a high chair and given candy while a rabbit was in a cage at a safe distance from him. • The rabbit was moved closer with each session and eventually placed in Peter’s lap. • By the final session, Peter had grown fond of the rabbit
  11. 11. PROPERTIES OF CONDITIONING • The stimulus for a particular conditioned learning is more or less specific .If a CR be established with a particular sound then different sound will be ineffective. • If a CR be not be practiced for several months it undergoes decay due to disuse or if CR be repeated several times without UCS (meat) then also the learning goes extinct. • The stimulus that follow with a reward is called positive reinforcement and the stimulus that associated with punishment is called negative reinforcement.
  12. 12. DISCRIMINATION Discrimination is the learned ability to distinguish between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus. If two (or more) different stimuli are simultaneously presented to the organism, and only one of them is associated with reinforcement regardless of position, the organism will learn to select the reinforced stimulus on future occasions.
  13. 13. DISCRIMINATION EXAMPLE: • Dogs were subjected to different tones but only at one particular tone they were rewarded .In the beginning dog could not discriminate between different tones but after repeated discrimination become refined and dogs could associate one particular tone with reward and salivate .The figure shows dog’s response with tone of 256c/s and 392c/s. In case of tone of 256c/s dog salivate because food is given at this tone . while in case of tone of 392c/s dog do not salivate.
  14. 14. DISCRIMINATION EXAMPLE: • In Wisconsin General Test Apparatus (WGTA),a monkey is provided with various shaped wooden blocks .whenever the monkey picked up triangle it was given a mild electric shock .After a few trials monkey completely stopped picking up triangle .This discrimination can be accelerated because of the punishment (negative reinforcement) by picking up triangle .
  15. 15. Sadiia rehaman