Today we will focus on two basic models of learning, classical and operant conditioning. Specific topics include:

Pavlov's classical conditioning and how it might be implemented in the nervous system.

Thorndike's law of Effect and its evolution into Skinner's operant conditioning. •A model: How operant conditioning operates together with basic motivations as an adaptive mechanism.

Uses and abuses of operant conditioning.

If there is time, we will consider the contributions of behaviorism against its "overclaiming".

Ivan Pavlov & lab

The CS as a Signal

• Evidence suggests that the CS serves as a signal for upcoming events. • Learning is less likely if the CS is

simultaneous with the US or follows it. • 0.5 second lead time optimal

• Learning occurs only if there is some contingency between the CS and US.

• Contiguity isn’t enough

Stimulus Generalization

Neural Basis of Learning

• The neural bases for learning involve diverse mechanisms, such as:• presynaptic facilitation• postsynaptic changes

• long-term potentiation (LTP)

• creation of new synapses • growth of new dendritic spines

Edward Thorndike

B. F. Skinner

Schedules of Reinforcement

• Partial reinforcement: The response is reinforced only some of the time. • schedule of reinforcement

• in ratio schedules, reinforcement after a number of responses; the ratio used may be fixed or variable

• in interval schedules, reinforcers for the first response made after a given interval since the last reinforcement; this interval can be fixed or variable

Extinction under fixed & variable schedules of reinforcement

Edward Tolman

Variations in Learning: Behavioral Challenges

• Observational learning

• Biologically biased learning

• Belongingness/expectations in learning

• “Smart” learning

Mirror Neurons

Conclusions: Broad Applications Coupled with Severe Limitations of the Behaviorist Viewpoint

Next: The Power Law of Practice: Learning just keeps going and going and going….