Chapter 4

• Classical conditioning


  The process whereby we learn to predict when and what we might eat, when we are likely to face danger, and when we are likely to be safe. It is also integrally involved in the learning of new emotional reactions (e.g., fear or pleasure) to stimuli that have become associated with a significant event.
• Systematic studies of classical conditioning

  • Began with the work of the great Russian physiologist Pavlov
  • Also independently discovered by Edwin Twitmyer in a Ph.D. dissertation submitted to the University of Pennsylvania in 1902
• Psychic secretions


  Stomach secretions elicited by food-related stimuli, which seemed to be a response to the expectation or thought of food
• Orosensory stimuli


  Distinctive texture and taste sensations in the mouth
• Object learning


  The association of one feature of an object with another
• Conditional stimulus (CS)


  The tone or light, whose effectiveness in eliciting salivation depended on pairing it several times with the presentation of food
• Unconditional stimulus (US)


  The food or sour taste, whose effectiveness in eliciting salivation did not depend on any prior training
• Conditional response (CR)


  The salivation that eventually came to be elicited by the CS
• Unconditional response (UR)


  The salivation that was always elicited by the US
• Pavlovian conditioning


  • Investigated in a variety of situations and species
  • Carried out with many different species using procedures developed primarily by North American scientists during the second half of the twentieth century
• Fear conditioning


  The conditioning of emotional reactions, such as fear and anxiety
• Freezing


  Immobility of the body (except for breathing) and the absence of movement of the whiskers associated with sniffing, a common defense response in anticipation of aversive stimulation
• Asymptote


  The limit of learning evident in fear conditioning experiments
• Lick-suppression procedure


  A conditioned suppression procedure where the ongoing behavior is licking a drinking spout that contains water, and the fear CS (e.g., tone) suppresses this licking behavior
• Lever press activity


  The behavioral baseline for the measurement of fear in conditioned suppression experiments, where rats are trained to press a lever for food reward and then come to suppress this lever pressing during the CS
• Eyeblink conditioning


  A prominent technique for translational research involving classical conditioning, where the eyeblink reflex is conditioned
• Eyeblink conditioning experiment


  • The paired group showed a significantly higher rate of eyeblinks to the CS from the beginning of the second session, while the unpaired control group did not
  • Illustrates that classical conditioning requires the pairing of a CS and US, and that the learning may not be observable at first
• Sign tracking


  Animals approaching and contacting stimuli that signal the availability of food
• Goal tracking


  Conditioned behavior where the animal tracks the goal object, which is food
• Individual differences in sign tracking and goal tracking

  • Correlated with individual differences in impulsivity and vulnerability to drug abuse
  • Genetically based, accompanied by differences in dopamine release in the reward circuit of the brain in response to the CS that signals food
• Conditioned taste preference


  Learned if a flavor is paired with nutritional repletion or other positive
• Conditioned taste aversion


  Learned if ingestion of a novel flavor is followed by an aversive consequence such as indigestion or food poisoning
• Taste-aversion learning


  • Can be learned with just one pairing of the flavor and illness
  • Can occur even if the illness does not occur until several hours after exposure to the novel taste
• Evaluative conditioning


  The process where our evaluation or liking of a stimulus is changed by having that stimulus associated with something we already like or dislike
• Excitatory Pavlovian conditioning


  Organisms learn a relation between a CS and US, and presentation of the CS activates behavioral and neural activity related to the US in the absence of the actual presentation of that US
• Short-delayed conditioning


  The most frequently used procedure for Pavlovian conditioning, where the US is presented after a brief delay following the start of the CS
• Trace conditioning


  Similar to short-delayed conditioning, but the US is not presented until some time after the CS has ended, leaving a gap (trace interval) between the CS and US
• Long-delayed conditioning


  Similar to short-delayed conditioning, but the US is presented after a longer delay following the start of the CS
• Intertrial interval


  The time from the end of one conditioning trial to the start of the next trial
• Pavlovian Conditioning


  A type of learning in which a neutral stimulus becomes associated with a meaningful stimulus and eventually elicits a similar response
• Interstimulus interval or CS-US interval


  The time from the start of the CS to the start of the US within a conditioning trial
• Ivan Petrorich Pavlov


  • His career started in the circulatory system then moved on the physiology of digestion
  • Developed a surgical procedure that enabled him to study the digestive processes of animals over long periods of time by redirecting an animal's digestive fluids outside the body, where they could be measured
  • He tested the salivary reflex of the dog and established what we know at the present as Pavlovian Conditioning
• Interstimulus interval or CS-US interval


  The time between the start of the conditioned stimulus (CS) and the unconditioned stimulus (US) within a conditioning trial
• Short-delayed conditioning


  CS starts each trial, US presented after a brief (less than 1 minute) delay, CS may continue during US or end when US begins
• Two Types of Reflexes

  • Unconditional reflexes - largely inborn, innate, permanent reflex
  • Conditional reflexes - acquired through experience, impermanent, "depend on very many conditions
• Trace conditioning


  CS presented first, US not presented until some time after CS has ended, leaving a gap called the trace interval
• Long-delayed conditioning


  CS starts before US, but US is delayed much longer (5-10 minutes or more) than in short-delayed procedure, no trace interval
• Unconditional Stimulus (US)


  Part of unconditional reflex, events that are important to survival, evoked behavior is unconditional response
• Simultaneous conditioning


  CS and US presented at the same time
• Unconditional Stimulus (US)


  • Meat powder