Week 10 - Learning Flashcards
(39 cards)
Define learning
The modern definition of learning stems from the learning theory and originated within the field of psychology specifically within the area of experimental behavioural analysis.
“A relatively permanent change in behaviour as the result of experience” Fred Skinner
Define memory
The modern definition originated from the information processing theory in the context of cognitive psychology and computational science.
“. The faculty of the mind by which it retains the knowledge of previous thoughts impressions or events” (cognitive psychology)
“The capacity to store and retrieve of information” (computational science)
Functions of the nervous system
Allow the organism to respond adequately to external stimuli. Continuously adapt to changing environmental conditions.
- find water
- find food
- find sexual partners
- avoid danger (predators, toxins)
- In general find optimal environmental conditions for survival
Are reflective responses sufficient to achieve adaptation?
Reflex is a simple allow a little flexibility and typically associate with invariable forms of external stimuli
Why might reflective responses not be enough?
Reflective responses may be sufficient to sustain basic forms of survival but complex and changing environments require specific adaptations.
A system that is fixed and immutable is not capable of learning. Think of robots or computers (allthough recent technological advance suggest we can create robots that may be able to learn from experience).
Our environment changes consistently.
Neural plasticity is the set of Physiological mechanisms that allow the modification of behavioural responses based on previous experiences. Plasticity sustains learning
The concept of plasticity
Learning depends on the plasticity of the circuits within the brain. The ability of the neuron’s to make lasting changes in the efficacy of their synaptic transmission.
The brain is thought to store information in networks on modified synapses and to retrieve this information by activating these networks.
Our understanding of the rules that govern association and the networking of neurons goes back to the groundbreaking work done by Donald Hebb in the 1950s
Hebb had the intuition that if two neurons Are active at the same time the synapsis between them strengthened.
Hebbian synapses
Donald Hebb postulated:
“When an axon of cell A is near enough to excite cell B and repeatedly or persistently takes part in firing it, some growth processes or metabolic changes take place in one or both cells such that A’s efficiency as one of the cells firing B, is increased”
The organisation of behaviour, 1949
What is the Hebbs Law often paraphrased as?
Neurons that fire together wire together
Aplysia Californica As a model system to study learning
Aplysia Has been used to study the physiological and molecular basis of learning and memory.
Aplysia has a respiratory organ (GILL) and a tube like organ used for taking up and expelling water (SIPHON).
In Aplysia, the Gill withdrawal reflex can be elicited both from the siphon and the mantle shelf, a structure that lies next to the siphon.
Repetitive stimulation of the siphon produces habituation of the withdrawal reflex.
There is no change in the sensitivity of the receptors for glutamate (an excitatory transmitter), but diminished release of the transmitter. Can last several weeks.
If the stimulus applied is inocuous Aplysia shows habituation. What happens, however, if the stimulus is aversive? For example, repeated electrical stimulation of the tail.
In this case, sensitisation occurs, a process whereby the response becomes progressively enhanced. This process may actually increase the responsiveness to innocuous stimulation (eg tactile stimulation of the siphon).
What are the four types of learning that Carlson postulated?
Perceptual
Motor
Relational
Stimulus response learning
Describe perceptual learning
Refers to the capacity to learn to recognise and learn about stimuli perceived previously and differentiate them from other similar stimuli.
The main function is to identify and categorise stimuli, such as objects in context or situations.
Define motor learning
Motor learning is a special type of stimulus response learning because it requires both exteroceptive sensory stimulation and propioceptive Sensory stimulation.
It requires feedback between the environment and the actions we perform.
What is relational learning?
Includes various forms of learning that is required to establish specific associations between stimuli.
For example, spatial learning involves the association between different stimuli present in a given context and allows the organism to respond adequately. Effective, we create a cognitive may of the environment to help us navigate through it.
What happens in habituation and sensitisation?
It is straightforward. We experience a stimulus, respond innately to it and then either stop responding or respond more strongly after repeated exposure. We have learned something significant, namely, what matters and what does not matter.
What is stimulus response learning (S-R) learning, and how does it make a connection between two stimuli or between our behaviour and its consequences?
Refers to the capacity to perform a learned behaviour is response to a specific stimulus with which the behaviour has been associated previously.
The responses can be mere reflexes or complex sequences of actions. The main forms of S-R learning are:
Classical conditioning
Instrumental (operant) conditioning
Classical conditioning - Ivan Pavlov
Ivan Pavlov (1849-1936), a Russian physiologist, discovered classical conditioning (also known as Pavlovian conditioning).
Earned the Nobel prize in 1904 for his discovery.
Does classical conditioning require consciousness?
Classical conditioning does not require consciousness and can occur even among people who are in a vegetative state. Bekinschtein et al. (2009) repeatedly delivered a musical note, followed by a puff of air to the eyes - a UCS that produces an UCR of blinking - to 22 patients in a vegetative or minimally conscious states. Eventually, the musical note became a CS, producing eye blocking in these largely or entirely unconscious patients.
What is one principle of classical conditioning; acquisition?
Learning phase during which a conditioned response is established.
What is one principle of classical conditioning; extinction?
Gradual reduction and eventual elimination of the conditioned response after the conditioned stimulus is presented repeatedly without the unconditioned stimulus.
What is one principle of classical classical conditioning; spontaneous recovery?
In a phenomenon whereby a seemingly extinct CR reappears (often in a somewhat weaker form) if the CS is presented again.
What is one principle of classical conditioning; renewal effect?
A related phenomenon to the spontaneous recovery is the renewal effect. This occurs when we extinguish a response in a setting different from the one in which the animal acquired it. When we restore the animal to the original setting, the extinguished response often reappears.
Thus extinction does not delete memories, memories seem to become “doormant” and can be reinstated.
What is a principle of classical conditioning; stimulus generalisation?
The process by which conditioned stimuli are similar, but not identical, to the original CS elicit a conditioned response.
The tendency to respond to stimuli similar to the CS is called generalisation. Pavlov conditioned the dogs salvation (CR) by using miniature vibrators (CS) I’m the thigh m. When he subsequently stimulated other parts of the dogs body, salivation dropped.
What’s a principle of classical conditioning; discrimination?
Discrimination is the ability to differentiate between a CS and other stimuli that have not been paired with an UCS.
The importance of classical conditioning:
Classical conditioning is not limited to salivating laboratory dogs or full withdrawal responses in Aplysia- it has important implications for everyday life.
The trick is to elicit a positive affective response and create a lasting association (eg present an attractive person and a product together at the same time = a positive emotional response).
