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CHAPTER ONE: BASIC DEFINITIONS

  • Learning: a realistically long-lasting change in behavior that results from experience with environmental events related to the behavior; 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 due to repeated or excessive use of a muscle.

  • Motivation: a hypothetical state that energizes responding (e.g., feeding, drinking, defence, mating, infant care).

  • Practice: repetition of a behavior that produced measurable improvements in performance; learning requires practice or experience related to the acquired behavior (e.g., pitching horseshoes).

  • Not all long-term changes in behavior are due to learning:

    • Maturation: changes due to physical or psychological development; practice may not be needed because growth alone may improve performance (e.g., dunking a basketball).
    • Evolution: changes across generations due to reproductive success; learning occurs on a much shorter timescale (an individual’s lifetime).

  • Learning, performance, & levels of analysis:

    • Performance: observable behavioral actions.
    • Learning may involve a potential change in behavior; learning can be behaviorally silent (latent learning).
    • Latent learning: learning that is not immediately manifested; a later test must reveal the learning; may be due to the relation between stimuli rather than a preformed response.
    • Learned behavior also involves long-lasting changes in brain mechanisms; learning typically involves changes in several systems at different levels.

  • LEVELS OF ANALYSIS (overview):

    • Molecular changes in individual neurons.
    • Connections between neurons (synapses).
    • Changes in neural systems (neural circuits or neurotransmitter systems).
    • Changes in behavior.

  • NATURALISTIC vs. EXPERIMENTAL OBSERVATIONS:

    • Naturalistic observation: observing and measuring behavior as it occurs in natural settings; no manipulations by the observer; descriptive information; cannot establish cause-effect.
    • Experimental observations: measuring behavior under conditions with manipulations; designed to test the effects of particular factors or variables; provides the only way to reach causal conclusions.
    • Since learning cannot be observed directly, it must be inferred; to conclude learning occurred, observed change must be due to experimental manipulations.
    • IV = independent variable = the specific training experience; DV = dependent variable = the resultant change in behavior.
    • The fundamental learning experiment: the IV must be manipulated to compare behavior in at least two conditions.
    • Experimental condition: the relevant experience or training.
    • Control condition: participants do not receive the relevant experience but are otherwise treated identically.
    • Learning is inferred by comparing behavior in the experimental vs. control conditions.
    • The control problem in studies of learning.

  • DESIGN ISSUES IN LEARNING RESEARCH (continued):
    1) Naturalistic observations cannot be used for causal conclusions because different individuals may have had different life experiences and past training histories.
    2) Therefore, the control procedure must be designed with care; individuals should be randomly assigned to two critical conditions.
    3) Between-group experimental design: comparing two separate groups of individuals.

    • Single-case experimental designs: valuable but can be misleading; results are presented individually and may not include explicit control groups.
    • Baseline data are required in single-case studies: observe behavior before the training procedure, compare during training to the baseline; without training, performance should remain at baseline.
    • ABA design: return to baseline after training (a refinement).
    • These designs can be translated into practical applications.

  • GENERAL-PROCESS APPROACH TO LEARNING:

    • Assumes learning mechanisms are the same across different learning situations; focuses on underlying commonalities to identify universal principles.
    • Example: engineers assume an internal combustion engine operates the same in a four-door sedan and a large SUV; basic principles of learning are assumed to generalize across contexts (e.g., a child learning to operate a tablet vs. a rat learning to navigate a maze).
    • Generally, these principles should generalize across species and situations, but this approach may not always be correct.
    • Natural selection may prepare different species to contend with different contingencies of survival; sensory and motor systems differ across species.

  • SPECIALIZATION & CONSTRAINTS ON LEARNING:

    • Some learning mechanisms may become specialized to natural contingencies of survival.
    • These cases are also called “constraints on learning.”
    • A commonly cited example is human language learning.

  • 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 animals’ genetics.
    3) Precision and control over the learning environment and administration of procedures.
    4) Ability to observe the same individuals under the same 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 necessary experimental manipulations/controls).
    2) Study behavior of plants (no nervous system; learning may not be present).
    3) Study individual cells or tissue cultures (without behavior, it’s hard to determine cell-mechanism importance).
    4) Study computer simulations (must first understand learning before simulating it).

  • SUMMARY (overview for CHAPTER ONE):

    • Learning is a basic process in behavioral adaptation.
    • Learning cannot be directly observed; it must be inferred from overt performance.
    • Learning must be distinguished from other forms of behavior change.
    • Methods to study learning should be adapted to the questions being asked.
    • Observational and experimental methods each have advantages and limitations.
    • Between-group and single-case methods can both be useful.
    • Studying the behaviors of both humans and nonhumans helps reveal similarities and differences in the science of learning.

CHAPTER TWO: SHAPING & HETEROGENOUS SUBSTRATES OF BEHAVIOR

  • All learned behaviors reflect an interaction between training procedures and preexisting behaviors; changes tend to fit with an organism’s preexisting behavioral tendencies, arising from prior genetic programming.
  • Shaping: a conditioning procedure that produces new behaviors by reinforcing successive approximations to the desired behavior.
  • UNCONDITIONED BEHAVIORS: unlearned behaviors, preexisting and genetically programmed; also called unconditioned responses by Pavlov.
  • CONCEPT OF REFLEX:
    • Reflex: the smallest unit of unconditioned behavior; the reflex is the relationship between a simple response and a specific environmental stimulus.
    • Examples: eyeblink after dust in the eye; a reflex arc links stimulus to response.
  • Rene Descartes (1596–1650): proposed the reflex as a reflection of stimulus energy into response energy.
  • THE REFLEX CONCEPT (restatement): reflexive responses elicited when a specific stimulus occurs reliably; a sudden loud noise can cause a startle.
  • REFLEX ARC: the entire S-R unit:
    1) Eliciting stimulus enters the spinal cord via a sensory neuron (e.g., shock from a live wire; nipple touching a baby’s cheek).
    2) Elicited response is transmitted to the muscles via a motor neuron (e.g., hand jerk; baby head turn toward nipple).
  • REFLEXES ARE CRITICAL FOR LIFE:
    • Respiratory reflexes enable breathing.
    • Suckling reflexes enable newborns to drink milk.
    • Swallowing and digestive reflexes; postural reflexes; withdrawal reflexes protect from injury.
  • MODAL ACTION PATTERNS (MAPS):
    • Ethology: study of evolution/development of functional units of behavior.
    • MAPs are organized patterns reliably elicited by a specific stimulus; also called instincts; exhibited by all animals including humans.
    • Sign stimulus: a particular feature of a stimulus sufficient to elicit a MAP.
    • Example: Pecking response of herring gull chicks is elicited by the red spot on a parent’s bill; the combination of the bill shape and red spot triggers pecking, which causes the parent to feed.
    • Other features of the parent are less important; this allows researchers to create Supernormal Stimuli.
  • MAPS:
    • MAPs are species-specific and often called fixed action patterns, though the term is imperfect because responses may vary between individuals and across time.
    • MAPs often involve the whole organism and may seem purposeful but are automatic.
    • MAPs have a strong genetic basis and are required for reproduction, caring for young, and protection.
  • REFLEXES & MAPS ARE BASIC UNITS OF PREEXISTING BEHAVIOR:
    • They are the substrate on which learning and conditioning operate.
  • DON’T CONFUSE CONSUMMATE AND CONSUME:
    • MAPs involve specific stimuli and responses.
  • MAPS OCCUR IN RESPONSE TO SIGN STIMULI:
    • Tasks involving MAPs are easier to learn because they are biologically prepared.
    • Tasks unrelated or contradictory to MAPs are hard or impossible to learn (biologically contra-prepared).
  • ORGANIZATION OF UNLEARNED BEHAVIOR:
    • The organization of unconditioned behavior generally does not require learning or experience.
    • Motivation: sign stimuli trigger MAP only if the organism is in a suitable motivational state; sign stimuli are releasing stimuli (releasers).
  • HYDRAULIC MODEL (motivation/drive framework):
    • Factors build hydraulic pressure, increasing motivation; hunger lowers the threshold for activating food-related MAPs in the presence of food-related sign stimuli; estrus lowers the threshold for reproduction-related MAPs in the presence of a male; performing the MAP reduces the pressure in the system.
  • APPETITIVE & CONSUMMATORY BEHAVIOR:
    • Appetitive behavior comprises the initial components of the behavioral sequence; highly variable and flexible; occurs before a sign stimulus.
    • Consummatory behavior completes the sequence; stereotyped and focused; ends the response sequence.
    • Feeding example:
    • Appetitive: foraging; a squirrel uses spatial cues to locate nuts/fruit.
    • Consummatory: eating the food (cracking the nut, chewing, swallowing).
    • Reproduction example:
    • Appetitive: male quail searches for a female and calls; consumption is the actual copulatory act.
  • BEHAVIOR SYSTEMS:
    • A behavior system is a set of response modes and modules.
    • It includes general search, focal search, and consummatory behaviors.
    • General search and focal search correspond to appetitive behaviors; the sequence proceeds from general search to focal search to consummatory.
    • A behavior system provides a detailed account of appetitive and consummatory behaviors.
  • SUMMARY (CHAPTER TWO):
    • All learning reflects an interaction between training procedures and preexisting behavioral organization.
    • Unconditioned behavior has its own determinate structure; it is not homogeneous or easily modified.
    • The simplest unit of behavior is the reflex.
    • MAPs are more complex forms of elicited behavior; elicited by sign or releasing stimuli.
    • Elicited behaviors are orderly sequences that begin with appetitive and end with consummatory behaviors.
    • A behavior system is a coordinated set of response modes for outcomes like nutrition, defense, or reproduction.
    • Ethological considerations should guide our understanding of learning; learning occurs against inherited stimulus–response possibilities.

CHAPTER THREE: HABITUATION & SENSITIZATION

  • Habituation: a decrease in the vigor of elicited responding.

  • Sensitization: an increase in the vigor of elicited responding.

  • These effects can occur in both simple and complex learning procedures and are extensively studied in reflex systems.

  • Descartes’ view:

    • The vigor of the elicited response is related to the intensity of the eliciting stimulus; reflexive responses were assumed automatic.
    • Modern understanding: reflexive behavior is modifiable by prior experience.

  • Habituation vs. sensitization dynamics:

    • Reflexive behavior to an eliciting stimulus may increase (sensitization) or decrease (habituation) in vigor.
    • These processes help focus attention on important stimuli and improve environmental interaction efficiency.

  • Orienting Response (OR):

    • The first reaction to an eliciting stimulus; index of attention to the stimulus.
    • Many stimuli do not require continued attention; reduced attention is observed in associative learning (latent inhibition).

  • Repeated presentations of eliciting stimuli:

    • Habituation and sensitization are observed across a wide range of species, including very simple organisms; highly conserved and adaptive.
    • Deficits in habituation/sensitization are observed in several neuropsychiatric conditions (schizophrenia, Parkinson’s disease, fragile X syndrome, autism spectrum disorder).

  • EFFECTS OF STIMULUS CHANGE ON HABITUATION:

    • We focus on habituation: various responses across species show habituation (earthworm bodily contraction, rat head shaking, cat leg flexion, human infant startle, rat startle).
    • Example: pupil dilation in barn owls in response to a sound.

  • PUPIL DILATION IN BARN OWL:

    • Pupil dilates on first presentation of a sound; dilation decreases with repetition (habituation).

  • FACTORS INFLUENCING HABITUATION:

    • Time since last stimulus.
    • Frequency and intensity of the eliciting stimulus.
    • Characteristics of the eliciting stimulus.
    • Introducing a novel stimulus before the eliciting stimulus.
    • These variations suggest habituation is a Central Nervous System (CNS) learning process, not simply sensory adaptation or motor fatigue.

  • EFFECTS OF TIME SINCE LAST STIMULATION:

    • Habituation effects can change over time; effects may decrease or disappear with time.
    • Spontaneous recovery occurs when a response recovers after a period without stimulation.
    • Long-Term Habituation: substantial spontaneous recovery does not occur (strong savings); considered genuine learning.
    • Short-Term Habituation: substantial spontaneous recovery does occur (weak savings); less convincing as genuine learning.

  • EFFECTS OF STIMULUS FREQUENCY AND INTENSITY:

    • Stimulus frequency: more frequent presentations lead to faster habituation but less durable habituation.
    • Stimulus intensity: low-intensity stimuli are expected to habituate faster than high-intensity stimuli, but results are inconsistent; results often depend on data analysis.

  • HABITUATION: ABSOLUTE VS. RELATIVE RESPONDING

    • ABSOLUTE RESPONDING: considers absolute response levels; initial scores differ with stimulus intensity; strong stimuli often show larger declines than weak stimuli.
    • RELATIVE RESPONDING: uses the percentage of the initial response (normalized to 100%); can invert apparent effects across intensities.

  • EFFECTS OF STIMULUS CHANGE - HABITUATION:

    • Response fatigue is a possible explanation for reduced responding; if fatigue underlies reduced responding, a novel but similar stimulus should not lead to recovery.
    • If habituation is responsible, a recovery in responding should occur when a novel stimulus is presented (differential recovery).
    • Dishabituation: exposure to a novel stimulus results in recovery of responding to a previously habituated stimulus (e.g., newly hatched chicks habituated to a predator call exposed to white noise later).

  • EFFECTS OF EXPOSURE TO A SECOND STIMULUS:

    • Sensory adaptation is a reduction in sensory receptor functioning; exposure to a second stimulus should not lead to recovery if adaptation causes the reduction.
    • Therefore, dishabituation can decisively rule out sensory adaptation as the cause of reduced responding.
    • Together, dishabituation and stimulus specificity provide strong evidence that habituation occurs in the CNS rather than peripheral sensory/motor systems.

  • THE S-R SYSTEM (diagrammatic description of habituation mechanism):

    • Three-neuron pathway:
      1) Sensory (afferent) neuron carries the stimulus into the nervous system.
      2) Interneuron connects afferent to efferent.
      3) Motor (efferent) neuron activates muscles to produce the response.
    • The key synapse for habituation links the sensory neuron and the interneuron.

  • CHARACTERISTICS OF SENSITIZATION:

    • Sensitization is less well-studied than habituation but is influenced by the same factors (frequency, intensity, etc.).

  • INTERACTION BETWEEN HABITUATION & SENSITIZATION:

    • Sensitization can modulate habituation; two-process theory was developed to account for dishabituation effects, though other theories exist.

  • SUMMARY (CHAPTER THREE):

    • Reflexive or elicited behavior is often viewed as automatic and invariant, yet it is sensitive to prior experience.
    • Repeated eliciting stimuli may lead to habituation (decreased responding) or sensitization (increased responding).
    • The magnitude and durability of habituation depend on the intensity and frequency of the eliciting stimulus.
    • Responding to one stimulus can be altered by prior exposure to a different stimulus (dishabituation).
    • Habituation shows stimulus specificity and dishabituation, indicating a CNS basis and constituting a bona fide form of learning that is widespread in the animal kingdom and potentially important for survival in a changing world.
    • However, habituation involves only a single event; later discussions will focus on learning that involves more than a single event: Stimulus–Stimulus (S-S) or Response–Stimulus (R-S) relations.