Lecture Notes Review: Learning, Shaping, Habituation & Sensitization
Chapter 1: Basic Definitions
Learning is a realistically long-lasting change in behavior that results from experience with environmental events and is shown by an increase or decrease in responding (excitation vs. inhibition).
Learning is not due to short-term changes in behavior (e.g., fatigue).
Fatigue: a temporary decrease in responding from repeated or excessive use of muscle.
Motivation: a hypothetical state that energizes responding (e.g., feeding, drinking, defense, mating, infant care).
Practice: repetition of a behavior that produces measurable improvements in performance (e.g., pitching horseshoes).
Learning requires some practice or experience related to the acquired behavior.
Not all long-term changes in behavior are due to learning; maturation and evolution illustrate alternative sources of change.
Maturation: changes due to physical or psychological development; growth alone can improve performance without practice.
Evolution: changes in behavior across generations due to reproductive success; learning occurs on a shorter timescale (an individual’s lifetime).
Performance and learning; levels of analysis
Performance: observable behavioral actions.
Learning may involve a potential change in behavior and can be behaviorally silent (latent learning) where a later test reveals learning without prior visible manifestations.
Learned behavior involves long-lasting changes in brain mechanisms, often across several systems and levels.
Latent learning
Latent learning refers to learning that is not immediately manifested in behavior; a test later reveals the learning.
It may reflect relations between stimuli rather than preformed responses.
Levels of analysis (overview)
Molecular changes in individual neurons.
Changes at the level of synapses (connections between neurons).
Changes in neural systems (neural circuits or neurotransmitter systems).
Changes in behavior.
Naturalistic vs. experimental observations
Naturalistic observation: observing behavior as it occurs in natural settings with no manipulations; descriptive only; cannot establish causality.
Experimental observations: measuring behavior under conditions with manipulations designed to test specific factors; can support causal conclusions.
Since learning cannot be observed directly, it must be inferred from changes in behavior under controlled conditions.
To infer learning, compare behavior under different experiences while keeping other factors identical.
Independent and dependent variables; fundamental learning experiment
Independent variable (IV): the specific training experience.
Dependent variable (DV): the resultant change in behavior.
Fundamental design requires comparing at least two conditions: experimental condition (relevant experience) vs. control condition (no relevant experience, but otherwise treated identically).
Learning is inferred by differences in behavior between the experimental and control conditions.
The control problem in learning research: isolating the effect of the training experience from other differences between individuals.
Page 3: Experimental design issues
Cannot rely solely on naturalistic observations due to variability in life histories and past training.
Random assignment is essential for control of confounds when comparing two critical conditions.
Between-group experimental design: comparing two separate groups (experimental vs. control).
Single-case experimental designs: valuable but can be misleading; results are often presented individually rather than as a group average; may lack an explicit control group.
Baseline data are essential in single-case studies; behavior is observed before training.
ABA design: baseline → training → return to baseline; a refinement for control.
Results from these designs have practical applications.
General-process approach
Assumes learning mechanisms are the same across different learning situations; aims to identify universal learning principles.
Example: use of internal combustion engine principles that generalize across vehicle types.
Learning principles should generalize across species and situations (e.g., a child learning to operate a tablet vs. a rat navigating a maze).
May not be correct in all cases; natural selection may tailor learning to species-specific contingencies.
Sensory and motor systems differ dramatically across species, which can limit generalization.
Chapter 4–5 preview: specialization and language
Later consideration of cases where learning mechanisms are specialized to survival contingencies (constraints on learning).
Human language learning is a commonly cited example of specialization.
NONHUMAN PARTICIPANTS IN LEARNING RESEARCH
Advantages of studying learning in laboratory animals:
1) Knowledge and control over prior learning experiences.
2) Knowledge of and ability to control genetics.
3) Precision and control over the learning environment and procedures.
4) Ability to observe the same individuals under identical conditions across trials.
5) Control over extraneous motivational variables.
6) Minimizes the role of language.
7) Minimizes animals’ attempts to please or displease the experimenter.Alternatives to nonhuman participants:
1) Observational research (no experimental manipulation).
2) Study behavior of plants (no nervous system to support learning).
3) Study individual cells or tissue cultures (needs behavioral context for relevance).
4) Study computer simulations (must understand learning first to simulate).SUMMARY: Learning is a basic process in behavioral adaptation; cannot be directly observed and must be inferred from performance; distinguish learning from other changes; employ appropriate methods; both between-group and single-case methods have value; studying humans and nonhumans reveals similarities and differences.
Chapter 2: Shaping & Heterogeneous Substrates of Behavior
Learned behaviors reflect an interaction between training procedures and preexisting behaviors
Changes in behavior align with an organism’s preexisting tendencies arising from prior genetic programming.
Shaping: a conditioning procedure that reinforces successive approximations toward a desired behavior.
UNCONDITIONED BEHAVIORS
Unlearned behaviors are often preexisting, genetically programmed responses essential in learning.
Also called unconditioned responses by Pavlov.
CONCEPT OF THE REFLEX: the smallest unit of unconditioned behavior; the relationship between a simple response and a specific environmental stimulus.
Example: eyeblink in response to dust in the eye.
Rene Descartes: reflex as a reflection of stimulus energy into response energy.
REFLEX ARC: the full S–R unit from stimulus input to response output.
REFLEX ARCS AND QUANTITIES
Eliciting stimulus → sensory neuron → spinal cord → interneuron → motor neuron → elicited response.
Example sequences: a touch to the cheek triggering sucking; a feather/fleck causing an eye blink.
REFLEXES ARE CRITICAL FOR LIFE (e.g., respiration, suckling, swallowing, postural reflexes, withdrawal).
MODAL ACTION PATTERNS (MAPS)
Ethology studies functional units of behavior.
MAPs are organized, reliably elicited sequences by a specific stimulus; also known as instincts.
Sign stimulus: a feature of the stimulus sufficient to elicit a MAP.
Example: Pecking by herring gull chicks triggered by the red spot on the parent’s bill and the bill’s shape; triggers feeding.
Supernormal stimuli: exaggerated sign stimuli that elicit stronger MAPs.
MAPS are species-specific/typical; examples: opossums playing dead, cats arching and hissing, rats freezing when frightened.
MAPs may seem thoughtful but are often automatic and have a strong genetic basis; essential for reproduction, care of young, and protection.
RELATIONSHIP BETWEEN REFLEXES AND MAPS
Both are basic units of preexisting behavior and provide the substrate for learning and training.
ORGANIZATION OF UNLEARNED BEHAVIOR
Organization of unconditioned behavior generally does not require learning.
Motivation: sign stimuli trigger MAPs only when an animal is in an appropriate motivational state; releasing/releaser stimuli.
HYDRAULIC MODEL: buildup of “drive” increases motivational state; performing a MAP reduces this pressure.
Hunger and estrus are examples that lower response thresholds in the presence of sign stimuli.
Appetitive vs. consummatory behavior:
Appetitive: initial components of the sequence; flexible and variable; occurs before sign stimulus.
Consummatory: completes the sequence; stereotyped and focused; ends the response sequence.
Feeding example: appetitive (searching for nuts/fruits) → consummatory (eating, biting, chewing).
Reproduction example: appetitive (seeking a mate, vocalizing) → consummatory (copulation, cloacal movement).
BEHAVIOR SYSTEMS
A behavior system is a coordinated set of response modes that achieve an important outcome (nutrition, defense, reproduction).
Modes include general search, focal search, and consummatory behaviors.
General search/focal search correspond to appetitive behaviors and reflect progression toward a goal.
This framework enriches understanding of appetitive and consummatory phases.
SUMMARY: Chapter 2 takeaways
Learning reflects an interaction between training procedures and preexisting behavioral organization.
Unconditioned behavior has a determinate structure; reflex is the simplest unit.
MAPs are more complex elicited behaviors, activated by sign stimuli, with strong genetic underpinnings.
Do not confuse MAPs with non-MAP behaviors; MAPs simplify learning by aligning with biology.
Behavior systems provide a framework for understanding the sequence from appetitive to consummatory actions.
Learning should consider inherited stimulus–response possibilities and predispositions.
Chapter 3: Habituation & Sensitization
Definitions
Habituation: a decrease in the vigor of elicited responding with repeated stimulation.
Sensitization: an increase in the vigor of elicited responding with repeated stimulation.
Both effects can occur in simple and complex learning tasks and are well-studied in reflex systems.
Descartes believed vigor of elicited responses is tied to stimulus intensity and that reflexes are automatic; modern findings show reflexive behavior is modifiable by prior experience.
Orienting response and latent inhibition
The Orienting Response is the initial reaction to a stimulus and indexes attention.
Not all stimuli require continued attention; latent inhibition describes reduced attention in associative learning paradigms upon prior exposure.
Repeated presentations and CNS involvement
Habituation and sensitization occur across a wide range of species and are highly conserved and adaptive.
Deficits in habituation/sensitization are observed in several neuropsychiatric conditions (schizophrenia, Parkinson’s, fragile X, autism).
Effects of stimulus change: habituation and dishabituation
Habituation can be influenced by time since last stimulus, frequency, intensity, stimulus characteristics, and exposure to a novel stimulus before the eliciting stimulus.
Many variations suggest habituation is a CNS learning process, not just sensory adaptation or fatigue.
Dishabituation: exposure to a novel stimulus can recover responding to a previously habituated stimulus.
Example: newly hatched chicks habituated to predator call later respond to white noise with renewed responding.
Effects of exposure to a second stimulus: sensory adaptation vs dishabituation
Sensory adaptation reduces the functioning of a sensory receptor and could cause reduced responding, but dishabituation shows recovery when a second stimulus is introduced, thereby ruling out adaptation as sole cause.
Together, dishabituation and stimulus specificity provide strong evidence that habituation occurs in the CNS rather than peripheral systems.
The S–R system (habituation mechanism)
Diagram: three-neuron circuit comprising:
Sensory neuron (afferent)
Interneuron
Motor neuron (efferent)
Steps in habituation:
1) Eliciting stimulus activates sensory neuron.
2) Interneuron stimulates motor neuron.
3) Motor neuron activates muscles to produce the response.The key synapse for habituation is the connection between sensory neuron and interneuron.
Sensitization: characteristics and interactions
Sensitization is less extensively studied than habituation but shares similar influencing factors.
It can modulate habituation; sometimes the same factors affect both processes.
The two-process theory and alternatives
The two-process theory was developed to explain dishabituation effects; other theories also account for observed patterns.
The gist: habituation and sensitization can interact, and context or prior experience can shift the balance.
SUMMARY: overall perspective on learning in habituation/sensitization
Reflexive or elicited behavior is often automatic but modifiable by experience.
Repeated elicitation can lead to habituation or sensitization; both depend on stimulus intensity and frequency.
The magnitude and durability of habituation depend on stimulus parameters and learning history.
Responses to a given stimulus can be altered by previous exposure to different stimuli (dishabituation).
Dishabituation and stimulus specificity support the view that habituation is a CNS-based form of learning, widespread in the animal kingdom and potentially important for adaptation to a changing environment.
However, habituation typically involves single-event exposure; broader forms of learning involve stimulus–stimulus or response–stimulus relations in subsequent discussions.
Summary and connections
Learning is best understood as an interaction between training procedures and preexisting biological organization, with both innate structures (reflexes, MAPs, behavior systems) and learned modifications shaping outcomes.
Distinguishing and integrating concepts like naturalistic vs. experimental methods, control designs, and various learning mechanisms (habituation, sensitization, latent learning) are essential for interpreting behavioral data.
The material emphasizes that learning is a CNS process with broad cross-species relevance and practical implications for psychology, neuroscience, and education.
Key LaTeX references
Three-neuron reflex arc: 3 neurons.
Sign stimuli and MAPs: sign stimulus as a feature triggering a MAP.
Appetitive and consummatory sequences: represented in the context of behavior systems.
Long-term vs short-term habituation and spontaneous recovery: distinctions in durability and credibility as evidence of learning.