Lecture 1 Flashcards
What is cognition? What is cognitive neuroscience?
How we think, feel, behave and act. Cognition includes all mental input and output, from basic activities (language, arithmetic) to complex decisions (understanding another person’s perspective).
Cog. neuroscience is based on information processing (transformation of sensory input into memory/action)
Milestones in Cog. Neuro. (X5)
1) Ability to record activity from single neurons in behaving animals
2) Ability to link activity patterns to ongoing cog. processes.
3) Renewed interest in relationship between brain injury and behaviour.
4) New techniques (PET, fMRI) - large neuronal populations correlated with behaviour.
5) Computational approaches
Shift in study of mental activity (Ebbinghaus, Thorndike) (What Thorndike believed)
Introspection –> experimental approach, championed by Ebbinghaus and Pavlov
Thorndike: developed puzzle boxes to test mechanical problem solving of cats and dogs. Measured time taken to escape and compiled learning curves. Naive animals were no quicker to learn if shown how to escape or exposed to animals performing the escape. Believed all learning was simply a result of stimulus-response and that this also applied to humans - animals learned by development of actions initially made by chance. Associations were strengthened by use if pleasurable and weakened with disuse if discomfortable (law of effect).
Eb”bing”haus: 16 nonsense syllables. Number of trials it took to repeat them twice with no error. Measured “savings scores” (fewer trials to relearn with each day). Also “meaningfulness effect”, “distributed practice” etc. Provided a precedent on which much of cognitive approach of 20th century based on
Behaviourism
Rise of experimental approach to studying behaviour –> behaviourism. E.g. Skinner, Watson.
Observation of behaviour under strict conditions. Anything in between stimulus and response deemed irrelevant.
Willard Small
“Mall”-Maze (NOT the blocked one)
First introduced mazes for studying learning. Noticed rats would choose shortcut despite being reinforced to run a different route. Major controversy - can learning be reduced to stimulus and response? Or must cognition, insight, motivation be taken into consideration?
Led to rise of cog. psychology (concerned with input, output AND in-between)
Aversion learning
Aversion learning AKA Garcia effect. E.g. sickness-induced aversion learning (associate taste with nausea). One of the first examples for innate learning (predisposition). But are LIMITS (rats can’t associate sound with nausea).
How can we tell if learning has occurred in animals?
Can’t speak so…
Learning only revealed by performance. This depends on RECALL.
Recall = the successful use of learned experience, or the expression of a response that was modified by learning
Learning produces a change in the nervous system (a memory). Could be transient (e.g. reverbatory activity) or may last lifetime (permanent physical change). Memory can’t be observed directly (we infer memory by examining behaviour - recall)
Engram
a hypothetical permanent change in the brain accounting for the existence of memory; a memory trace
Recall depends on… (X3)
The extent to which to material was originally stored in memory (e.g. did any learning take place?)
If the material is still available (was it forgotten?)
The timing of events (e.g. info may be irrelevant at the time so don’t learn it or may not have been useful for a long time so recall is more difficult)
3 main forms of learning. Examples. How are they adaptive?
1) Non-associative (repeated exposure to single stimulus)
e. g. habituation (reduction in effectiveness of stimulus. Adaptive as it saves time/energy. E.g. aplysia)
2) Associative (exposure to 2/more stimuli that have particular relationship to one another)
(adaptive as it causes animal to be aware of events that produce changes in environment)
E.g. classical conditioning and instrumental conditioning
3) Complex learning (may involve insight or reasoning e.g. novel routes through maze, using tools etc). E.g. win-stay, lose-shift strategy (monkeys will learn to do this with almost no error, more naive animals do not) (Peanut under a or b. If picked correct one, optimal strategy is to stay, if not, optimal strategy is to shift.)
Unconditioned and conditioned responses
Unconditioned: US (food) –> UR (salivation). ROBUST reflex.
Conditioned: acquired through EXPERIENCE (so less robust). Pairing of a neutral stimulus with the US (e.g. bell)
Operant Conditioning
AKA instrumental conditioning
Skinner box. The OPERANT is a behaviour. Experimenter changes how often animal displays behaviour by associating with positive or negative reinforcement. Skinner claimed this was NOT the result of stimulus-response learning because animals allowed to behave spontaneously - they have control over the stimuli, unlike in classical conditioning.
CLASSICAL conditioning pairs two stimuli whereas operant conditioning pairs behaviour and response.
