Lecture Notes: Psychology of Learning - Overshadowing vs Blocking in Classical Conditioning
Key Concepts
Overshadowing and Blocking are phenomena in classical conditioning.
This topic is discussed in Chapter 7 of the course material.
Overshadowing
Definition: Occurs when a compound stimulus is presented before an unconditioned stimulus (US).
Compound Stimulus: Involves two stimuli being presented simultaneously.
Process:
One stimulus is more salient or stronger than the other.
The stronger stimulus becomes classically conditioned, while the weaker does not.
Explanation: Information value explanation.
The more salient stimulus provides more useful information to the organism.
Consequently, the stronger stimulus is classically conditioned.
Blocking
Definition: Involves pairing a neutral stimulus with the US before adding a second stimulus.
Process:
Pair one neutral stimulus with the US.
Add a second neutral stimulus to create a compound stimulus.
Present both stimuli simultaneously before the US.
Test both stimuli individually to determine which becomes classically conditioned.
The first stimulus that was paired with the US becomes conditioned, while the second does not.
Explanations:
Information Value Explanation:
The first stimulus provides useful information to the organism by the time a second stimulus is introduced.
The second stimulus provides no new information and thus is not conditioned.
Rescorla-Wagner Theory:
Proposes a maximum amount of learning possible, represented by Lambda (位).
The first stimulus uses up all the potential learning represented by 位 when paired with the US.
When a second stimulus is added, no more learning can occur because 位 has been exhausted.
Mention of competing explanations, with a total of four explained for blocking, though only two were discussed here.
Additional Notes
Remember that these concepts are critical for understanding classical conditioning and the explanations highlight how organisms associate stimuli based on information value and possible learning limits.