PSY352H5 Lecture Notes - Lecture 6: Memory Consolidation, Learning, Habituation
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Lecture 6
Animal learning and memory
• Animals can adapt to conditions at a much quicker rate through learning than through evolution
• Learning: Experience dependent change modification of behavior
Learning and memory are perhaps the most exciting phenomena among all behaviours
• Learning allows adaptation to the environment the most flexible way
• No need to wait for generations of selection, i.e. evolutionary change
• Modification of behaviour comes quickly due to experience
Practically any organism can learn
• Learning and memory have been demonstrated in a wide variety of species
• Chimpanzees can learn complex tasks including sign language
• Dogs learn to respond to a large number of human signals appropriately
o They are genetically predispositioned to easily learn
o Dogs were selected to work well with humans
o Some say that humans are also selected to work well with dogs as it can give us an
advantage
o Selection pressure may have changed our ways of looking at dogs
• Rats learn to navigate mazes to find reward
• Pigeons learn to peck at the appropriate button to obtain food
• Fish respond to light associated with shock
• Fruit flies associate odour cues with tapping
• Even worms, like the nematode Caenorhabditis elegans can learn and remember: associative
learning with olfactory cues
o Their olfactory cues are linked to associative cues
o Can associate the smell and taste of a cue with a reinforcer
Learning and memory are crucial and thus have been demonstrated in a wide variety of species
• Learning and memory represent a series of processes that allow experience dependent
modification of behaviour
• Learning:
o Attending to stimuli
o Acquiring information about stimuli (associations)
• Memory:
o Consolidation of acquired information
o Storage of information
o Recall (retrieval) of information
There are many forms of learning and memory
• There are many ways one could classify or categorize these different forms
• Whether these categories are due to historical, pragmatic classifications or whether they represent
biologically meaningful distinct processes is a question under intense debate and investigation
Forms of learning
• Non-associative learning (there is nothing to associate)
o A particular stimulus is repeatedly given, the organism either becomes responsive to it or
hypersensitive to it
o Habituation (when the stimulus is not harmful), sensitization (when the stimulus is
dangerous)
Non-associative learning
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• Skill learning (motor learning)
• Get better and better
Associative learning
• Stimulus-stimulus association (classical conditioning)
o A conditioned stimulus which is neutral and has no value
o Unconditioned stimulus which is the reinforce causes either positive or negative
reinforcement
▪ Eg. Food is a positive reinforce
• Stimulus-response association (instrumental or operant conditioning)
o The associations between a stimulus and response
o Eg, sniffy the rat
o If the rat just randomly presses the level they get a reward and over time they realise the
two are linked
Latent learning (no “external” reinforcement)
• When animals walk around a maze they learn the maze without any reinforce
• Because novelty itself is reinforcing and is interesting
Observation based learning (learning by observing others performing a task)
• Just from watching the animal can learn from another organism doesn’t require a reward
• Assumes a complex representation of reality in the mind in animals
• Requires the animal to imagine a sense of self and puts themselves in the place of the organism
that is doing it
o Parrots and corbids can do this along with chimps and apes
o Dogs cannot do observational based learning
Creative learning (executive function)
• Come up with a rule and by learning from the previous task the organism can create a general rule
that they can use for other similar but different activities
• A form of abstract learning
Simple forms of learning: habituation and sensitization
Skill learning: Motor learning
• Hard to explain but you get better with practice
• The brain becomes fine tuned and enables it to respond to tiny signals
• What the cerebellum does
• It is not conscious because it has to be vary fast
• Referred to as muscle memory but the memory is stored in the brain
• You can show that there is memory but you cannot recall it
• motor learning in mice, they get better at stay on the rod
• there is a gradual learning increase
• the ones that did a little bit worse had a genetic mutation that prevents cerebellum function
Associative learning: pavlovian conditioning
Examples of associative conditioning: context and cue dependent fear
• in the first condition the rat enters chamber and the tone cue is presented
o base learning
• next there are two possible conditions
o tone cue alone with new chamber
o put the animal back in the same training chamber but without tone cue
• the animal freezes in both cues
• shows that the animal learned both chamber and the tone cue
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• if the animal has an abnormal hippocampus it will not respond well to the context, it will not
remember that it was shocked in that chamber (black dots)
Examples of associative conditioning: spatial learning
• Morris water maze
• Rats look for invisible platform
• Mice want to escape because they don’t like water, rats are a little better with water
• Once the mice finds the platform, they get rewarded by being placed in a nice warm environment
• The mice see the spatial cues that lie around maze and use that to locate the platform
• After a week long learning they are able to learn their way around the maze increasingly well
A hippocampal dependent spatial learning and non-hippocampual dependent control tasks
• not just good enough to find one platform, they have to find all the other cues
• in the second platform, the platform that rotates, but it does not require spatial learning and it is a
simple associative tasks
• the associative task is a control for the spatial learning
o because we can tell if the animal doesn’t mind the water
o motor function
o what if the animal lacks perceptual cues
• the associate task is a good comparison for the spatial learning version because the tasks are
relatively the same
o the only difference is that in the associative conditioning it is a simple CS, UCS relation
o but in the spatial learning task, it requires recognition of multiple different stimuli
• there is no test for learning, we can only test for learning performance (not memory)*
Examples of associative learning: spatial learning
• measure cumulative distance
• by the end of the training the rat gets to the target quickly or they are searching very close to the
target
• in the second graph the strain origin of the wild type are different
Conditioned taste aversion
• unusual because in most learning tasks time is important
• in this task time doesn’t matter the animal will still associate the two
• pair the food with a lithium chloride injection that makes the animal feel sick (the reinforce)
• the animal will avoid the food (conditioned stimulus- the olfactory cue)
• Unusually long delay between conditioned stimulus (CS = taste) and unconditioned stimulus (US
= nausea) and unusually long lasting memory (conditioned response = food avoidance)
• Only need a couple pairing and the animal will not go back to that food for forever or for atleast a
very long time
Constraints and genetic predispositions in learning
• Learning itself is under selection pressure
o Under the influence of genes and natural selection
• Not everything can be learnt, and not everything can be learnt with the same efficiency or in the
same manner
• Species-specific characteristics
o A particular species will be good at learning certain species in certain ways
o Not everything will be learned in the same manner across species
• Adaptive, ecologically relevant features
Human learning: Is it limitless???
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Document Summary
Animal learning and memory: animals can adapt to conditions at a much quicker rate through learning than through evolution, learning: experience dependent change modification of behavior. 1: skill learning (motor learning, get better and better. Associative learning: stimulus-stimulus association (classical conditioning, a conditioned stimulus which is neutral and has no value, unconditioned stimulus which is the reinforce causes either positive or negative reinforcement, eg. Food is a positive reinforce: stimulus-response association (instrumental or operant conditioning, the associations between a stimulus and response, eg, sniffy the rat. If the rat just randomly presses the level they get a reward and over time they realise the two are linked. Latent learning (no external reinforcement: when animals walk around a maze they learn the maze without any reinforce, because novelty itself is reinforcing and is interesting. Observation based learning (learning by observing others performing a task)
