Learning and Memory

Introduction

A college student studies late at night for an organic chemistry midterm, trying to memorize numerous reactions.
The student uses coffee to stay awake and the quiet library to minimize distractions, employing previously successful study habits.
Flashcards are used to rehearse reactants and products, with missed cards set aside for later review.
The student questions whether this memorization will last until the final exam in two months.
The chapter will cover memorization techniques and learning new behaviors.
The information aims to help answer MCAT questions and improve memory skills for both academic and professional (medical) careers.

Learning

Psychologically, learning is defined as acquiring new behaviors.
A stimulus is anything an organism can respond to, including sensory inputs.
Behavioral learning is based on the combination of stimuli and responses.
Responses to stimuli can change based on frequency and intensity.

Habituation

Repeated exposure to a stimulus can decrease response, known as habituation.
Example: Medical students initially react strongly to cadavers or lacerations but become less bothered over time.
A subthreshold stimulus is too weak to elicit a response.

Dishabituation

Dishabituation is the recovery of a response to a stimulus after habituation.
Often occurs when a second stimulus is presented, interrupting the habituation process and increasing response to the original stimulus.
Example: On a long car trip, habituation occurs to the sensations of highway driving. Exiting the highway introduces a new stimulus, causing dishabituation and renewed awareness of the original stimuli.
Dishabituation is temporary and refers to changes in response to the original stimulus.

Types of Learning

Learning is a change in behavior in response to a stimulus.
The MCAT focuses on associative learning and observational learning.

Associative Learning

Associative learning involves creating an association between two stimuli or between a behavior and a response.
Two types: classical and operant conditioning.

Classical Conditioning

Associative learning that uses biological, instinctual responses to create associations between unrelated stimuli.
Ivan Pavlov's experiments with dogs are a prime example.
Some stimuli cause innate physiological responses (e.g., salivating at the smell of bacon).
An unconditioned stimulus causes a reflexive response.
The innate response is an unconditioned response.
Neutral stimuli do not initially produce a reflexive response.
In Pavlov's experiment:
- Unconditioned stimulus: meat (causes salivation)
- Neutral stimulus: ringing bell
Pavlov repeatedly rang the bell before giving the dogs meat.
Eventually, dogs salivated upon hearing the bell alone.
The neutral stimulus (bell) became a conditioned stimulus.
The reflexive response to the conditioned stimulus is a conditioned response.
Acquisition is the process of turning a neutral stimulus into a conditioned stimulus using a reflexive unconditioned stimulus.
Salivation in response to food is an unconditioned response, while salivation in response to the bell is a conditioned response.
Conditioned responses are not necessarily permanent.
Extinction is the loss of a conditioned response if the conditioned stimulus is repeatedly presented without the unconditioned stimulus.
Example: if the bell rings repeatedly without meat, the dog may stop salivating.
Spontaneous recovery: After extinction, presenting the conditioned stimulus again may produce a weak conditioned response.

Modifying Conditioned Responses

Generalization: A stimulus similar to the conditioned stimulus can also produce the conditioned response.
Example: Little Albert was conditioned to fear a white rat and later also feared a white stuffed rabbit, a white seal skin coat, and a man with a white beard.
Stimuli discrimination: An organism learns to distinguish between similar stimuli.
Pavlov's dogs could discriminate between bells of different tones if one tone was paired with meat and another was not.

Operant Conditioning

Examines how the consequences of voluntary behaviors change the frequency of those behaviors.
Distinguishes between reinforcement and punishment.
Associated with B.F. Skinner, the father of behaviorism.
Behaviorism posits that all behaviors are conditioned.
Animals seek resources, and these behaviors are modified over time.

Reinforcement

Reinforcement increases the likelihood of a behavior.
Positive reinforcement: increases the frequency of a behavior by adding a positive consequence or incentive after the desired behavior.
- Example: Employees continue to work if they are paid.
Negative reinforcement: increases the frequency of a behavior by removing something unpleasant.
- Example: Taking aspirin reduces a headache, making it more likely you’ll take aspirin next time you have a headache.
Any reinforcement increases the likelihood a behavior will be performed.
Negative reinforcement is subdivided into escape learning and avoidance learning.
- Escape learning: an animal experiences an unpleasant stimulus and performs the desired behavior to remove the stimulus.
- Avoidance learning: the animal displays the desired behavior in anticipation of the unpleasant stimulus, avoiding it.
Example: Seat belt warning in a car progresses from escape learning to avoidance learning.
- Initially, the beeping noise (unpleasant stimulus) stops when the seat belt is buckled (escape learning).
- Eventually, the driver buckles up before driving to avoid the beeping (avoidance learning).
Positive and negative refer to the addition or removal of a stimulus, not whether the behavior is good or bad.

Classical and Operant Conditioning Combined

Dolphin trainers use reinforcers to train dolphins.
Feeding a fish is a primary reinforcer because it's a natural treat.
Trainers use a clicker paired with fish to elicit the same response through classical conditioning.
The clicker becomes a conditioned reinforcer or secondary reinforcer.
The trainer's presence becomes a discriminative stimulus, indicating a reward is potentially available.

Punishment

Punishment reduces the occurrence of a behavior.
Positive punishment: adds an unpleasant consequence to reduce a behavior.
- Example: Flogging a thief to deter stealing (also called aversive conditioning).
Negative punishment: removes a stimulus to reduce a behavior.
- Example: A parent forbidding a child from watching television due to bad behavior.

Reinforcement Schedules

The rate of acquiring desired behaviors is affected by the reinforcement schedule.
Two key factors: fixed or variable, and ratio or interval.
- Fixed ratio (FR): Reinforces a behavior after a specific number of performances. Example: rewarding a rat with food every third time it presses a bar.
  - Continuous reinforcement: a fixed ratio schedule where the behavior is rewarded every time.
- Variable ratio (VR): Reinforces a behavior after a varying number of performances, but the average number of performances is constant. Example: rewarding a rat after two, then eight, then four, then six button presses.
- Fixed interval (FI): Reinforces the first instance of a behavior after a specified time period. Example: a rat gets a pellet for the first lever press after sixty seconds.
- Variable interval (VI): Reinforces a behavior the first time it’s performed after a varying interval of time. Example: a rat might have to wait ninety seconds, then thirty seconds, then three minutes for a pellet.
Variable ratio schedules are fastest for learning a new behavior and are most resistant to extinction.
Fixed schedules (fixed ratio and fixed interval) often have a brief pause in responses after reinforcement.

Shaping

Shaping is rewarding increasingly specific behaviors that become closer to a desired response.
Example: Training a bird to spin and peck a key. Reward slight turns, then larger turns, then complete spins, and finally, pecking the key after spinning.
Shaping can lead to training extremely complicated behaviors.

Cognitive and Biological Factors in Associative Learning

Classical and operant conditioning are not the only factors affecting behavior.

Latent Learning

Learning that occurs without a reward but is spontaneously demonstrated once a reward is introduced.
Example: Rats carried through a maze perform just as well as rats trained with standard operant conditioning once incentivized with a food reward.

Problem Solving

Involves stepping outside the behaviorist approach.
Young children use trial and error when putting together jigsaw puzzles.
Older individuals analyze the situation and respond correctly the first time.
Humans and chimpanzees avoid trial and error by observing and then acting decisively.

Preparedness

Animals are predisposed to learn behaviors based on natural abilities and instincts.
Behaviors that coincide with natural behaviors are easier to learn.
Example: Birds naturally peck for food, so rewarding them for pecking-based behaviors works well.

Instinctive or Instinctual Drift

Animals revert to instinctive behaviors after learning a new, similar behavior.
Example: Raccoons trained to place coins in a piggy bank eventually rubbed the coins together and dipped them instead, reverting to their food-washing instinct.

Observational Learning

Learning a new behavior or gaining information by watching others.
Albert Bandura's Bobo doll experiment: Children who watched an adult attack an inflatable clown toy later exhibited similar violence.
Observational learning can also teach individuals to avoid behavior.
Children who saw the adult scolded after attacking the Bobo doll were less likely to be aggressive themselves.

Neurological Factors

Mirror neurons play a significant role.
Located in the frontal and parietal lobes of the cerebral cortex.
Fire both when an individual performs an action and when they observe someone else performing that action.
Involved in motor processes, empathy, and vicarious emotions.
Mirror neurons fire both when we experience an emotion and when we observe another experiencing the same emotion.
Play a role in imitative learning by primates.

Modeling

Observational learning through modeling affects an individual's behavior.
People learn acceptable behaviors by watching others.
Violent media or domestic abuse can serve as models for antisocial behavior.
Prosocial modeling can be just as powerful.
Observational learning is strongest when a model's words match their actions.
Children disproportionately imitate what a model does rather than what they say.