Transcript Getting smart by learning (Lecture 3)

Learning (Lecture 3)
The goal: Survival in face of unknown challenges
The tools:
a. Adaptation of society across generations
by genetic change.
b. Adjustment of individuals by exploitation of
the genetic endowment:
Unconditioned behaviors.
Conditioned (learned) behaviors.
Perspectives on learning
Behaviorist: Simple associations between
events and behaviors are the building
blocks of complex learning.
Cognitive: Flow of information…knowledge.
Biological: Brain plasticity, synaptic
strength.
Ethological: Species specific learning
constrained by genetic endowment.
21/11/05
Explanation in psychology
 Finding: Learning.
 Explanation:
Psychological generalization:
Hypothetical structure
explains the learning process
(predictive value of CS…).
Biological reductionism:
Biological structure explains
the learning process
(synaptic plasticity).
Biological reductionism
Sub-Neuronal
level
Behavior
Neurons
level
Systems
level
Computational
models at all
levels
Measuring behavior: then and now
Thorndike’s
Puzzle Boxes
Modern
technology
Classical conditioning (1)
Classical conditioning (2)
 Unconditioned behavior: US-UR
Reflex arc
Tabula rasa? (Locke)
 Conditioned behavior: CS-CR
 Association-contingency: CS-US
Contingency = ‫מקרה‬
time & space
 UR - CR: motor & emotional
 2nd order conditioning: CS serves as US
Classical conditioning (3)
 Temporal CS-US contiguity ? Contiguity is not enough !
 Contingency - cognitive predictability of US by CS.
 Biological up and down modulation of synaptic strength.
Contiguity = ‫סמיכות‬
Classical conditioning in aplysia:
Prediction of future in aplysia ?
Classical conditioning (4)
Clinical examples:
Anticipatory nausea in chemotherapy
Placebo effects
Craving for drugs
Panic attacks
Phobic responses
Motor balance restoring reflexes
From classical to operant conditioning
Operant learning (1)
Active organism
Simple trial-and-error
Learning: behavioral operation on the
environment & feedback from the environment
Law of effect: selection of responses that are
followed by positive feedback.
Research strategy - World degraded to absurdum
Shaping of creativity? Is it possible?
Operant learning (2)
Feedback from the environment:
Reinforcement: behavior up
+ reinforcement: after the response
- reinforcement: terminated by response
Punishment: behavior down
Operant learning (3)
Clinical examples:
Patient adherence
Frequent attending
Drug dependence
Token economics
Complex Learning
Cognitive perspective:
Acquisition of mental representations of the
world.
Thought as a simulation of the reality.
Operate on mental representations (VR?).
From behaviorism to cognitive sciences
Tolman’s cognitive map
Mental representation of
the space and not a
sequence of left-right
turns
Neuroscience perspective (1)
Most learning laws are based on Hebb’s rule
dated 1949:
if two neurons are simultaneously active,
then ….
the connection between them gets stronger
Learning = plasticity of Hebbian synapse
Neuroscience perspective (2)
END