Classical Conditioning

Classical Conditioning

1. Pavlov's experiments

   • Awarded Nobel Prize in Physiology in 1904-work on salivation of dogs.
   • Studeied digestove processes of lab animals by surgically implanting test tubes into cheeks of dogs to measure salivary response to different kinds of foods.

2. Basic Principles

   • Acquistion
   • Second Order Conditioning
   • Extinction
   • Spontaneous recovery
   • Generalisation
   • Discrimination
   • Understanding drug overdoses

3. Conditioned Emotional responses

   • Case of Little Albert (Watson and Rayner 1920)
     • A healthy and well developed child. By Watson's assessment "stolid and unemotional"
       • Study: Could he be classically conditioned to experience a strong emotion: fear?
         • Intially showed no fear to following stimuli: a white rat, a dog, a rabbit, various maska and a burning newspaper.
           • Tried to make him afraid: Whilst Albert was watching Rayner, Watson unexpectedly struck a large steel bar with a hammer producing a loud noise.
             • Albert cried, trembled and was generally displeased.
               • Wanted to show that a complex reaction could be conditioned using Pavlovian techniques. Also, shows fear can be learnt and that classical conditioning can be applied to animals.
                 • Ethics: Did not follow up with Albert or mother. This type of study could not be conducted today
                 • Learning and environemnt determine behaviour more so than genetics or personality. This conflicted with views at the time.
             • Presented him with a rat, as he went to touch it steel bar struck. After much repetition the ight of the rat alone caused Albert to recoil in terror.
               • Little Albert also showed stimulus generalisation-sight of white rabbit, a seal-fur coat and Santa Claus mask produced same reaction.

4. A deeper understanding of classical conditioning

   • Neural Elements
     • Amygdala plays an importance role in experience of emotion, including fear and anxiety. This is key to emotional conditioning, particularly the central nucleus.
       • Rat: CS-US pairings. CS tone and US mild electric shock. When rats experience painful stimuli in nature they show a defensive reaction and are motionless. Automatic nervous systems go to work. Heart rate and blood pressure increase and hormones asssociated with stress are released.
         • When fear conditioning takes place the behavioural and physiological components occur and are now elicited by CS.
           • Central nucleus of amygdala has a role in producing these responses through connections with other parts of the brain.
             • If connections linking midbrain to amygdala are disrupted the rat does not exhibit behavioural response (freezing). If connectionbs between amygdala and hypothalausm are severed autonomic respisnes asscoaited with fear cease. (LeDoux et al., 1988)
               • Amygdala is involved in fear conditioning in people as well as rats (Phelps & LeDoux, 2005)
   • Cognitive elements
     • Why didn't Pavlov's dogs salivate to Pavlov? Why didn't they form an association with him? he delivered the food! Similarly if Watson was present when the unpleasant US was sounded , why didn't Little Albert come to fear him?
       • Classical conditioning only occurs when an animal has learned to set up an expectation (Allan Wagner 1972)
         • The sound of a tone, beause of systematic pairing with food, set up a congitive state for lab dogs. pavlov did not as he had no reliable link with the food. In fact responses are being conditioned in this instance-tone sounds and dog wags tail, make begging sounds and look towards food source. (jenkins et al 1978)
           • Rescorla-Wagner model. Conditoming easier when CS was an unfamiliar event than when familiar. Familiar events have expected associationg making new conditioning difficult.
             • Adam didn't recoil horror every time he saw his daughter Carly although she was present during aqusition stage of 9/11/2001. Her familiarity made her a poor CS for Adam's fear conditioning - thankfully.
   • Evolutionary Elements
     • This type of learning can have adaptive value. Research on adaptiveness focused on three key areas: conditoned food awareness, conditioned food preferences and biological preparedness.
       • Food aversions
         • Hummus example: Psychology professor went for interview and ate bad hummus-very ill next day and didn't get job.
           • Never ate hummus again. Classical conditioning? Hummus-CS, toxicity US and gastric distress-UR. Nausea became linked to the hummus resulting in aversion to hummus
             • Unusual Aspects: US couldn't be the food as none of the other guests were ill. Time between hummus and distress was sevral hours-normally response is quicker. The most baffling is that the aversion was cemented after a single aqusition-usual takes serveal pairings of US and CS to establish pairings.
               • Any spcie that consumes a variety of foods or forgaes needs to develop a mechanism to avoid food that has made it ill.
                 • Rapid learning prevents death.
                 • Conditioning should be able to take place over long intervals-several hours. Toxic substances don't cause illness immediately so the organism needs to form association between food and illness over long term.
                 • Should develop aversion from smell or taste not ingestion-more adaptive. Learned aversion occur more often with novel foods than familiar ones-not adaptive to develop an aversion to everything you have eaten that day
                   • (Garcia and Koelling 1966) Series of studeies with rats. Findings: weak or no conditioing when CS was visual, auditory or tactile. Strong food aversion developed when stimuli had a distinct taste and smell.
                     • In one experiemnet they presented water accompanied by bright lights and tinkling sounds as the CS-little or no aversion observed.
                       • However if the CS was water laced with harmless but a flavoured novel substance such as strawberry researchers found a strong aversion to smell and taste of strawberry. If this was a familiar food aversion was much less likely.
                         • Food aversions can be acquired when organism is unconscious. Rats who were administered a toxic substance while under anesthesia developed a taste aversion to foods eaten when awake. (Rabin and Rabin 1984)
                           • Cancer patients who experience nausea from treatments often develop aversions to food they ate before therapy. (Broberg and Bernstein 1987) reasoned that, if the findings with rats generalised to humans, a simple tehcnique could minimise negative consequences.
                             • They gave patients a 'novel' food at end of last meal before treatment causing a food aversion to this unusual item rather than more common foods they were more likely to eat.
                             • These studies suggest that evolution has provided species with a kind of biological preparedness so that behaviours are relatively easy to condition in some species but not in others
                               • Birds depend on visual cues for finding food, however it is easy to use an unfamiliar visual stimulus such as brigfhly coloured food. (Wilcoxon, Dragoin, & Kral, 1971).
                               • Conditioning works best with stimuli that is biologically relevant to the organism. (Domjan 2005)
                           • Other research reveals a parallel-organisms learn to prefer particular substances (Sclafani 1995)
                             • Rats given flavoured water and nutrients delivered directly to stomachs. On other occasions a different flavour was used but paired with delivery of water to stomachs.After only a few trials devloped a preference for the flabour paired with sucrose.
     • Biological Predispositions for conditioning.
       • Humans have biological predisposition to develop phobias from our evolutionary past which were dangerous to survival. (Ohman and Mineka 2001). A physcially vulnerable specie with poor eye sight needs to be wary of predators that lurk in the night. A species that spends a great deal of time in trees will live longer if they develop an appreciation of the danger of falling. This shows we are biologically prepared for easy classic conditioning to fear circumstances that are ironically no longer life threatening.

5. Can Animals Learn Language?

   • Rico (Border Collie from Germany) may have a remarkable word learning ability. (Kaminski, Call, & Fischer, 2004).
     • Appears capable of learning new words through fast mapping-simple association.
       • When a child is presented with a new object and is told it's a mouse-child links sound with object and learns word.
         • Can also occur through inference: dad points to a group of three animals-dog, cat and unknown creature and calls it a duck. Child infers that this is the name of the unfamiliar creature.
           • This with tried with Rico-he returned with unfamiliar object 7/10 times. When tested 4 weeks later could pick them out of a diaply containing 4 well known and four strange objects 3/6times.
             • Performance comparable to three year old! Fast mapping not strictly human ability. Rico can match meaning with sound. Basic perceptual and cognitive processes that underlie learning of language are a good deal older than believed.
         • Some animals capable of this with limitred vocab. Rico however knows names of 200 objects and can fetch them on command.
           • Not clear if Rico has a cognitive sense or whether he has learnt through associations between sound and object and has embedded them in a game of go fetch.