L2 - PSYC2050: Blocking and Superconditioning in Classical Conditioning

Course Overview and Administrative Structure

PSYC2050 Learning and Cognition

• Blackboard: This is the primary resource for the course, containing the course handbook, lecture slides, lecture recordings (via Echo), tutorial slides, and staff contact details.

• Tutorial Structure: Tutorials focus on applying lecture material through experimental labs, discussing classic theoretical effects, generating hypotheses, conducting experiments, and discussing results.

• Semester Plan:

  • Week 1: Online tutorial.

  • Computer-based Experimental Labs: Occur in weeks $2$, $8$, $9$, $10$, and $11$.

  • Major Assignment Labs: Three labs devoted to the major project in weeks $4$, $5$, and $7$ (or weeks $3$, $4$, and $6$ as per specific schedules).

  • Discussion-based Labs: Week $12$ (Comparative Cognition lecture discussion).

Assessment Breakdown

There are two noted structures for assessment distribution:

Structure A:

• Self-monitoring Assignment: $40\,\%$

  • Due: $2\text{:00 pm}$ Tuesday, $6\text{th}$ October.

• Tutorial Worksheets: $10\,\%$

  • Based on Understanding of in-class cognitive experiments (hypotheses, IVs, DVs, results).

  • Conducted in weeks $8$, $9$, $10$, and $11$.

  • $3/4$ worksheets = $10\,\%$.

  • $2/4$ worksheets = $5\,\%$.

  • Less than $2 = 0\,\%$.

• Final Exam: $50\,\%$

Structure B:

• Quiz: $15\,\%$

  • Held during week $6$ (scheduled for April $2\text{nd}$).

  • $12$ multiple choice questions ($1\,\%$ each) and $2$ short answer questions ($1.5\,\%$ each).

  • $20\text{ minutes}$ duration.

• Self-monitoring Assignment: $45\,\%$

  • $40\,\%$ for the essay and $5\,\%$ for a draft operational definition (approximately $8\text{ sentences}$).

• Final Exam: $40\,\%$

Detailed Assessment Requirements

• Final Exam Details:

  • Conducted during the exam period ($07/11/2026 - 21/11/2026$ or June block).

  • Online and closed-book, usually in-person.

  • Assesses all course content.

  • Format: $38$ multiple choice questions ($1\,\%$ each) and $8$ short answer questions ($1.5\,\%$ each).

  • Time allocation: $10\text{ minutes}$ planning + $90\text{ minutes}$ completion (or $60\text{ minutes}$ for some versions). Backtracking is permitted.

• Self-monitoring Assignment:

  • Compulsory hurdle to pass the course.

  • Word count: $2,500\text{ words}$ ($\pm 10\,\%$, range: $2,250 - 2,750\text{ words}$).

  • Format: APA $7\text{th}$ edition.

• Generative AI Policy: Use is optional and permitted but must be disclosed on the Cover Sheet. Inappropriate use includes submitting unverified content, sharing personal information, or uploading library resources to AI platforms.

Foundations of Classical (Pavlovian) Conditioning

Core Definitions and Elements

Classical conditioning is learning via association, accidentally discovered by Ivan Pavlov while studying the digestive systems of dogs.

• Unconditioned Stimulus (US): A stimulus that elicits an innate, unlearned response (e.g., tasty food, electric shock).

• Unconditioned Response (UR): The unlearned, natural reflexive response to a US (e.g., salivation, distress).

• Conditioned Stimulus (CS): A neutral stimulus that does not initially elicit the response but to which an organism learns to respond after pairing with a US (e.g., a bell, a researcher, a light).

• Conditioned Response (CR): The learned response to a CS (e.g., salivation when hearing a bell, avoidance when seeing a light).

Experimental Phases

1. Habituation: The CS is presented alone. It involves a decline/disappearance of a reflexive response when the same stimulus is repeatedly presented. It is considered the simplest form of learning and does not require linking stimuli together.

2. Acquisition: The CS is presented along with the US. This is the phase where learning of the association occurs.

3. Extinction: The CS is presented alone again after acquisition has occurred, leading to a decrease in the CR.

The Predictive Brain

From a cognitive perspective, classical conditioning is about minimizing surprise and maximizing sensory evidence for models of the world. This is often referred to as the Bayesian brain or free energy principle.

Timing and Determinants of Classical Conditioning

Order and Timing Procedures

• Delay Conditioning (Short-delay): The CS is presented and continues until the US is presented. This is generally the most effective method.

• Delay Conditioning (Long-delay): Similar to short-delay, but the CS is presented for a longer duration before the US appears.

• Trace Conditioning: The CS is presented and then turned off before the US is presented. The time between the end of the CS and the start of the US is the "trace interval."

• Simultaneous Conditioning: The CS and US are presented at the exact same time.

• Backward Conditioning: The US is presented before the CS. This is generally ineffective for excitatory learning.

• Temporal Conditioning: The US is presented at regular time intervals (e.g., every $24\text{ hours}$); the passage of time itself becomes the CS.

Interstimulus Interval (ISI)

The optimal interval between the CS and the US varies depending on the system being studied:

• Eyelid Reflex: Optimal ISI is approximately $200 - 400\text{ ms}$.

• Taste Aversion: Optimal ISI can be several hours ($1 - 6\text{ hours}$ or more).

Factors Influencing the Acquisition Curve

1. Intensity/Salience of the US: More intense stimuli (e.g., tastier food vs. tasteless food) lead to more rapid acquisition.

2. Order and Timing: CS coming before the US is superior.

3. Previous History: If a CS was previously inhibitory, acquisition will be slower.

Advanced Learning Processes and Phenomena

Excitatory vs. Inhibitory Conditioning

• Excitatory Conditioning: The CS predicts the occurrence of a US ($A \rightarrow US$).

• Inhibitory Conditioning: The CS predicts the absence of a US. For example, if $A$ is paired with the US, but the compound stimulus $AB$ results in no US, $B$ becomes an inhibitor.

Testing for Conditioned Inhibition

1. Summation Test: Present a new excitatory CS ($N$) alone, then present it with the inhibitor ($N + I$). The combination should evoke a weaker CR than $N$ alone (N + I < N).

2. Retardation Test: Train an inhibitor ($I$) and a neutral stimulus ($N$) to both become excitatory ($I \rightarrow US$ and $N \rightarrow US$). Learning to the inhibitor will be significantly slower (I < N).

Clinical and Emotional Applications

• Watson & Rayner (1920): The "Little Albert" study demonstrated the acquisition of emotional responses (fear) to a white rat by pairing it with a loud noise. This resulted in generalized fear towards similar stimuli (e.g., rabbits, fur coats).

• John B. Watson's Claim: He asserted that any infant could be trained into any specialist (doctor, thief) regardless of talent or ancestry through behavioral conditioning.

Extinction and Memory Persistence

Extinction is not the erasure of the original association, as evidenced by several phenomena:

• Spontaneous Recovery: The reappearance of the CR after a break/pause following extinction.

• Renewal Effect: Extinction is context-specific. If acquisition occurs in Context X and extinction in Context Y, returning to Context X will cause the CR to reappear.

• Reinstatement (Reminder Effect): Presenting the US alone after extinction can cause the CR to return when the CS is presented again.

Blocking and Superconditioning

These phenomena challenge the standard assumptions of classical conditioning, such as equipotentiality (any two stimuli can be paired) and contiguity (more pairings equal stronger associations).

Blocking (Kamin, 1968)

• Definition: We do not learn about a novel CS if it is paired with an excitatory CS that is already predictive of the US.

• Mechanism: The US is not surprising, so no new learning occurs for the added stimulus.

• The Pizza Case: If anchovies ($A$) always cause a dodgy stomach ($US$), and you eat a pizza with anchovies and capsicum ($C$), you blame the anchovies ($A$) and learn nothing about the capsicum ($C$). Capsicum is "blocked."

Superconditioning (Rescorla, 1971)

• Definition: Learning is faster if a novel stimulus is paired together with an inhibitory stimulus (one that predicts the absence of the US).

• Mechanism: The occurrence of the US is highly surprising when an inhibitor is present, leading to accelerated associative strength for the novel stimulus.

• The Pizza Case: If beef ($B$) always predicts the absence of a dodgy stomach (inhibitory), and you eat a pizza with beef and deep-fried prawns ($D$) and get a dodgy stomach, you are surprised. You learn very quickly that deep-fried prawns ($D$) are the cause.

Predictor Strength Ranking

Ranking toppings or stimuli from strongest predictor of the US to the strongest predictor of the absence of the US:

1. Excitatory Stimulus (A): Anchovies / Stock A.

2. Superconditioned Stimulus (D): Deep-fried Prawns / Stock D.

3. Control Stimuli (E/F): Eggplant and Fresh Tomatoes / Stocks E and F (learned at a normal rate).

4. Blocked Stimulus (C): Capsicum / Stock C (lowest predictive strength among those that were paired with the US).

5. Inhibitory Stimulus (B): Beef / Stock B.

Practice Questions and Exemplary Responses

Question 1: Explain the difference between blocking and superconditioning.

• Response: Blocking occurs when nothing is learned about a novel Conditioned Stimulus (CS) that is paired with an excitatory CS (one already predictive of the Unconditioned Stimulus, or US). Superconditioning occurs when learning to a novel CS is faster because it is paired with an inhibitory stimulus (one that predicts the absence of the US).

Question 2: Describe three factors that affect the speed of acquisition of a conditioned response (CR) using an experimental example.

• Factor 1: Temporal Relationship: The interval between the CS and US (ISI). For example, in eyeblink conditioning (US = air puff, CS = tone, CR = blinking), an interval of $2\text{ seconds}$ results in faster acquisition than an interval of $10\text{ seconds}$.

• Factor 2: Intensity/Salience of US: More intense US leads to faster learning. For example, using highly preferred tasty food leads to faster acquisition than using tasteless food.

• Factor 3: Previous Inhibitory History: If a stimulus was previously an inhibitor, it takes longer to become an excitatory stimulus (retardation). For example, if a tone predicted the absence of a US, learning to associate that tone with the presence of a US will be slower than for a neutral tone.

Questions & Discussion

Participant: Which novel topping would you ignore and learn the least about? Response: The one paired with the excitatory stimulus (anchovies), which was capsicum. Because we are not surprised by the illness, we attribute it to the known cause and ignore the new one.

Participant: Which novel topping would you learn very quickly about? Response: Deep-fried prawns, because they were paired with beef. Since beef usually predicts no illness, getting sick is a major surprise, causing rapid learning about the new addition.

Participant: What is the point of presenting the eggplant ($E$) and fresh tomatoes ($F$)? Response: These serve as a control group. In rigorous experimental design, they allow us to see if the blocking and superconditioning manipulations were successful. For this to be true, deep-fried prawns must be more predictive than $E/F$, and capsicum must be less predictive than $E/F$.

Participant: Regarding the Stock Market game, what were the CS and US? Response: The Stocks were the Conditioned Stimuli (CS), as they were initially neutral and had to be learned. The Change in the Market was the Unconditioned Stimulus (US).