L&M Lecture 5 - General Learning Principles

Goals of Learning Research

• identify principles that are general to many situations

  • helps predict behaviour

  • helps modify behaviour

• identify factors that impact the strength, speed and efficacy of learning

  • classical conditioning

  • instrumental conditioning

Factors Affecting Conditioning

• Frequency — higher the frequency of pairings, more evidence of conditioning

  • hits an asymptotic limit (max)

• Intensity — a) salience of the CS/S_d b) salience of the US/reinforcer

  • a) e.g. brighter or dimmer light — rate of learning faster for more intense CS — but both reaches same asymptotic limit 

  • b) e.g. electric shock weaker/stronger — differences in total amount of learning (asymptote diff) (more salient — greater amount of learning)

• Contiguity (timing) — how far apart the events occur 

  • learning gets worse and worse as ISI is longer (but ISI should not be 0) 

  • caveat of taste aversion 

• Contingency — statistical relationship between events 

  • need 2 piece of info 

    • what is the probability of the US given the CS 

    • what is the probability that the US occurs anyways (in absence of CS) 

  • CS has to increase probability of the US 

What is Learning

• enduring change within organism brought about by experience that leads to a change in behaviour 

• enduring — changes are relatively stable 

• experience — previous trials (history), practice, observation 

Learning is not Equal to Performance 

• learning often reflected by change in behaviour

• not all changes in behaviour are examples of learning 

• no behaviour or performance does not always reflect no learning 

• performance is affected by learning but also depends on: 

  • opportunity

  • motivation

  • sensory and motor capabilities

changes in performance (or lack of) does not always reflect changes in learning (or lack of)

Learning is not… 

• reflexes — these changes in behaviour are not brought about by experience — are innate 

• instincts — these changes in behaviour genetically determined — more complicated than reflexes 

• maturation — changes brought about by aging 

• fatigue — change in behaviour is not enduring 

Reflex

• automatic, usually very fast 

• learning not required 

• eliciting stimuli → corresponding response 

• e.g. food → salivation, knee tap → knee jerk, pain → withdrawal

• generally helpful 

• involves the fewest neurons out of any behaviour type 

• sensory (afferent) nerves detect stimuli — motor (efferent) nerves stimulate muscles 

Instinct

• behavioural sequence which are largely genetically determined

  • typical of all members of a species

• diff between reflexes and instinct — complexity of behaviour not type

Maturation 

• changes that take place in your body and in your behaviour because getting older

• e.g. learning to walk

Fatigue

• transient state of discomfort and loss of efficiency as normal reaction to emotional strain, physical exertion, boredom or lack of rest 

• may lead to physical inability to perform learned response — not evidence of lack of learning 

Simplest Forms of Learning

• habituation

• sensitisation

Habituation

• decreased responding produced by repeated stimulation

• e.g. rat jumps less w each presentation of loud noise

Habituation is not…

• fatigue

  • fatigue occurs when muscles become incapacitated so org can no longer perform response

  • rat can still jump

• sensory adaptation

  • sense organs become temporarily insensitive to stimulation

  • rat can still hear sound

Sensitisation 

• increased responding produced by repeated stimulation 

• decrease in the threshold required to elicit response 

• e.g. rats run more in response to same amt of cocaine if pre-exposed to cocaine — more sensitive to the cocaine

Why Habituate and Sensitise

• helps sort out what stimuli to ignore and what to respond to — helps use organise and focus our behaviour in a world of meaningless stimuli

• habituation is adaptive — prevents wasting energy on safe stimuli

• sensitisation is adaptive — helps avoid harmful stimuli