Pavlov's research

• The mechanisms of classical conditioning were discovered accidentally by Pavlov (1897), a physiologist who was measuring the volume of specific enzymes in dog saliva
• Pavlov had been working with dogs in his lab:

  • The dogs were attached to an apparatus which held them in place and collected their saliva
• Pavlov noticed that the dogs began to salivate before they saw or smelt their food

  • They began to salivate when they heard the footsteps ofthe lab assistants approaching (the dogs had learned thatthese footsteps = food!)
• Pavlov was astounded by this discovery as he believed the dogs should only salivate when presented with the UCS - food - rather than an NS (footsteps)
• To test what he had just discovered he set up the following procedure:

  1. Dog given food as usual (UCS)
  2. Dog salivates when it sees and smells food (UCR)
  3. A bell is sounded (NS) every time dog is given food (UCS)
  4. A bell is sounded every time food is presented (the pairing of NS and UCS)
  5. After repeated pairings, dog salivates when it hears bell
  6. Bell has become the CS
  7. Dog salivating to sound of bell has become the CR
  8. Dog continues to salivate to bell however when Pavlov stopped pairing bell and food he found CR decreased and gradually disappeared (known as 'extinction')
• Pavlov's classical conditioning procedure: