Psychology of Learning

Unit 1: Foundations & Reflexive Learning

Key Terms

2 × 8 Factorial Design: A factorial design with two independent variables, one having two levels and the other having eight levels; the notation indicates the number of levels of each IV.

A Priori Method: A way of fixing belief through pure reasoning, independent of empirical experience; conclusions depend on the quality of premises.

a-Process: In opponent-process theory, the initial emotional reaction to a stimulus; fast-acting, remains at maximum strength while the stimulus is present, and decays rapidly when the stimulus ends.

Acquisition: The initial learning phase in classical conditioning during which the CS-US association is formed and the CR begins to appear.

Afferent Neurons: Sensory neurons that carry signals from receptors to the central nervous system; the first component of a reflex arc.

Anhedonia: The inability to feel pleasure; a manifestation of the strengthened opponent process in former drug addicts.

Aplysia: A marine snail (sea slug) with a simple nervous system used extensively in research on the neural mechanisms of habituation and sensitization.

Appetitive US: An unconditioned stimulus, such as food, that is sought out and elicits approach behaviors.

Attachment Behavior: The formation of strong emotional bonds between infants and caregivers, considered a prepared behavior in humans.

Autoshaping: Another term for sign tracking; the tendency for organisms to direct behavior toward stimuli that predict relevant events.

Aversive US: An unconditioned stimulus, such as electric shock, that is avoided and elicits avoidance or withdrawal behaviors.

Axon Terminals: The end portions of neurons where neurotransmitters are released into synapses.

b-Process: In opponent-process theory, the opponent emotional reaction that follows the a-process; slower to develop, strengthens with repeated presentations, and decays slowly.

Babinski Reflex: An infant reflex in which stimulation of the sole of the foot causes the toes to fan out; typically disappears by age 2.

Backward Conditioning: A timing arrangement in which the US precedes the CS, producing minimal or no conditioning.

Bait Shy: A phenomenon in which rats that survive poisoning develop taste aversions to the poison’s flavor, making them nearly impossible to poison again with that particular bait.

Basic Emotions: The six emotions recognized universally across cultures: anger, disgust, fear, happiness, sadness, and surprise (Ekman, 1973).

Behavioral Approach: The approach to studying learning that emphasizes observable behaviors and environmental causes while avoiding discussion of unobservable mental processes.

Behavioral Repertoire: The range of behaviors an organism is capable of performing based on what it has learned.

Behaviorism: The approach to psychology that focuses exclusively on observable behaviors and their environmental causes, avoiding discussion of mental states.

Between-Subjects Factor: An independent variable for which different participants are assigned to each level; also called independent groups factor.

Blocking: A cue competition effect in which prior conditioning of one stimulus precludes the conditioning of a second stimulus; even though the second stimulus is perfectly paired with the US, it gains little or no associative strength because the first stimulus already predicts the US.

Causal Inference: The determination that changes in one variable cause changes in another variable, the ultimate goal of experimental research.

Circumplex: A circular arrangement used to represent relationships among emotions; Plutchik’s model arranges eight primary emotions in opposing pairs around a wheel.

Classical Conditioning: A learning process in which a neutral stimulus comes to elicit a response after being paired with an unconditioned stimulus.

Cocktail Party Effect: The ability to focus attention on one conversation while filtering out background noise; relies partly on habituation.

Cognitive Approach: The approach to studying learning that emphasizes understanding mental processes such as memory, attention, expectation, and reasoning.

Cognitive Dissonance: A motivational state occurring when a person has two incompatible thoughts; the discomfort motivates behavior to reduce the inconsistency.

Cognitive Map: A mental representation of spatial relationships in an environment, as demonstrated in Tolman’s maze experiments.

Comparator: A component of motivational systems that compares actual input (current state) with reference input (desired state) and activates behavior when discrepancy exists.

Comparator Hypothesis: A theory proposing that the strength of the CR depends on comparing the CS’s association with the US to the strength of other stimuli’s associations with the US; what matters is relative predictiveness rather than absolute associative strength.

Comparator Mechanism: In kineses, the mechanism that compares current conditions to a reference level and initiates movement when conditions are unfavorable.

Comparator Stimuli: Stimuli other than the CS that are present during conditioning and testing; the CR depends on comparing the direct CS-US association to the indirect path through these other stimuli (typically the context).

Comparative Psychology: The study of behavior across different species, examining both similarities and differences in learning mechanisms.

Compensatory CR: A conditioned response that is opposite to the UR and seems to compensate for the UR’s effects; the CR opposes rather than mimics the UR, as seen in drug tolerance where contextual cues elicit responses opposite to drug effects.

Conditioned Emotional Response (CER): An emotional reaction elicited by a CS that has been paired with an aversive US, often measured by its ability to suppress ongoing behavior.

Conditioned Excitation: A type of conditioning in which the presence of the CS predicts that the US will appear shortly, causing production of a CR.

Conditioned Inhibition: A type of conditioning in which the presence of the CS signals that the US will not occur, inhibiting or preventing the expected response.

Conditioned Response (CR): The learned response elicited by the conditioned stimulus after conditioning has occurred.

Conditioned Stimulus (CS): A previously neutral stimulus that comes to elicit a conditioned response after being paired with an unconditioned stimulus.

Conditioned Suppression: The reduction in ongoing behavior caused by presentation of a CS that has been paired with an aversive US.

Conditioned Taste Aversion: A technique using taste aversion learning principles to protect livestock from predators without killing them; leaving treated meat for predators creates aversions that reduce livestock predation while preserving predator populations.

Confounding Variable: An extraneous variable that varies systematically with the independent variable, making causal inference impossible.

Contingency: The predictive relationship between the CS and US; the probability that the US will follow the CS.

Contraprepared Behaviors: Behaviors that are extremely difficult or impossible to learn because they conflict with evolved predispositions.

Control Group: In an experiment, the group that does not receive the treatment being studied; provides a baseline for comparison.

Critical Period: A specific time window in development when an organism is especially receptive to learning a particular behavior.

CS+ (Excitatory CS): A conditioned stimulus that has been paired with the US and signals that the US will occur.

CS- (Inhibitory CS): A conditioned stimulus that signals the US will not occur; a safety signal.

Cue Competition: Effects in which the conditionability of a stimulus is influenced by the presence of other stimuli; to-be-conditioned stimuli appear to compete with each other for the ability to become a CS and predict the US.

Cue Facilitation: A phenomenon that occurs when pairing a compound CS with a US results in enhanced conditioning to one of these cues rather than competition between them.

Cultural Transmission: The spread of learned behaviors through a population via social learning; behaviors pass from individual to individual through observation rather than genetic inheritance.

Delay Conditioning: A timing arrangement in which the CS begins before the US and continues during US presentation, producing the strongest conditioning.

Description: A goal of science involving accurately portraying phenomena.

Determinism: The assumption that behavior is orderly and systematic, not random, and that every behavior has causes that can potentially be identified.

Disconfirmed: The status of a theory that has been contradicted by evidence; in science, theories can be supported or disconfirmed but never conclusively proven.

Discoverability: The assumption that it is possible to discover the orderly relationships governing behavior.

Discrimination: The learned ability to respond to one stimulus but not to similar stimuli; the converse of generalization.

Dishabituation: The recovery of a habituated response following presentation of a novel stimulus.

Drive: In Hull’s theory, the motivational state (such as hunger or thirst) that energizes behavior.

Dual-Process Theory: The theory proposed by Groves and Thompson stating that habituation and sensitization occur simultaneously when a stimulus is presented, with behavior reflecting the stronger process.

Efferent Neurons: Motor neurons that carry signals from the central nervous system to muscles and organs; the final component of a reflex arc.

Emotion: Physiological changes and conscious feelings of pleasantness or unpleasantness, aroused by external or internal stimuli, that lead to behavioral reactions.

Empirical Observation: Observation based on sensory experience and data collection; the foundation of scientific knowledge.

Empiricism: The philosophical position that knowledge comes from sensory experience and observation.

Equipotentiality Assumption: The traditional conditioning assumption that any CS could be equally well conditioned with any US; this assumption was violated by taste aversion research showing that certain stimuli associate more readily with certain outcomes.

Ethology: The study of animal behavior in natural environments; ethologists identified fixed action patterns and sign stimuli.

Evolutionary Adaptation: Changes in behavior that occur across generations through natural selection rather than individual learning.

Experimental Control: The systematic manipulation of one variable while holding everything else constant to isolate causal effects.

Experimental Design: A general plan for selecting participants, assigning participants to experimental conditions, controlling extraneous variables, and gathering data.

Experimental Group: In an experiment, the group that receives the treatment being studied.

Experimental Neurosis: Neurotic behavior created by bringing excitatory and inhibitory tendencies into conflict through impossible discrimination tasks.

Explanation: A goal of science involving understanding why phenomena occur by identifying causes and developing theories.

Exposure Therapy: A clinical treatment for anxiety disorders based on extinction principles, involving repeated presentation of feared stimuli without the aversive outcome.

External Validity: The extent to which research findings generalize beyond the specific study to other populations, settings, and times.

External Stimuli: Stimuli received from the environment through sense organs that can trigger emotional responses.

Extinction: The reduction in conditioned responding that occurs when the CS is presented repeatedly without the US.

Extraneous Variable: An undesired variable that may operate to influence the dependent variable and potentially invalidate an experiment.

Extinction: The reduction in conditioned responding that occurs when the CS is presented repeatedly without the US.

F-Ratio: In ANOVA, the ratio of variance between groups to variance within groups; a large F-ratio indicates the independent variable has an effect.

Facilitated Reacquisition: The phenomenon in which an extinguished CR is reconditioned more rapidly than original conditioning; demonstrates that extinction doesn’t completely eliminate the CS-US association but suppresses it.

Facilitating Interneurons: Neurons involved in sensitization that enhance neurotransmitter release from sensory neurons, amplifying responses.

Factorial ANOVA: An inferential statistical test used to analyze data from factorial designs; tests main effects and interactions.

Factorial Design: An experimental design with more than one independent variable.

Factorial Mixed-Groups Design: A factorial design with at least one between-subjects IV and at least one within-subjects IV.

Fatigue: A temporary state affecting performance that does not involve learning.

First-Order CS: A conditioned stimulus that has been directly paired with an unconditioned stimulus.

Fistula: A surgical opening created by Pavlov to collect and measure salivation directly from a dog’s salivary gland.

Fixed Action Pattern: An elicited, stereotyped response sequence displayed by all members of a species; triggered by sign stimuli and runs to completion once initiated.

Flooding: A technique for treating phobias by presenting patients with highly feared cues that aren’t removed until fear subsides; produces extinction by exposing patients to the CS without the US until the CR diminishes.

Forward Conditioning: A timing arrangement in which the CS precedes and predicts the US, producing effective conditioning.

Generalization: The tendency for stimuli similar to the CS to elicit the CR; the more similar the stimulus, the stronger the response.

Generalization Gradient: The pattern of responding across stimuli varying in similarity to the CS, showing maximum responding to the original CS and decreasing responding as stimuli become less similar.

Gill-Withdrawal Reflex: In Aplysia, the reflexive withdrawal of the siphon and gill when touched; used extensively to study habituation and sensitization.

Grasp Reflex: An infant reflex in which stimulation of the palm causes the hand to close tightly around the stimulating object.

Habituation: A decrease in the strength of an elicited response resulting from repeated presentations of the stimulus.

Hebb’s Law: The principle that neurons which are repeatedly activated at the same time will develop stronger connections; often summarized as ‘neurons that fire together, wire together.’

Heliotropism: A tropism in which plants grow toward a light source due to differential growth rates on shaded versus illuminated sides.

Higher-Order Classical Conditioning: A procedure in which a neutral stimulus is paired with an already-conditioned CS, allowing the neutral stimulus to elicit a CR without ever being paired with the original US.

Human Universals: Traits, behaviors, and institutions (such as music, religion, marriage, and facial expressions of emotion) that appear in every known human culture; evidence of evolved species-typical behavioral tendencies.

Hypothesis: A testable prediction derived from a theory.

Hypothetical Construct: A theoretical concept that cannot be directly observed or measured but is inferred from observable behaviors.

Imprinting: A rapid form of learning in which young animals form a strong attachment to the first moving object they see, typically occurring during a critical period.

Incentive: A property of reinforcement that increases or decreases its reinforcing effectiveness.

Independent Groups: Groups of research participants formed by random assignment; each participant appears in only one group.

Independent Variable (IV): The stimulus or aspect of the environment that the experimenter manipulates to determine its influence on behavior.

Instinct: A complex, species-typical behavior pattern that occurs without prior experience.

Instinctive Drift: The tendency for learned behaviors to drift toward instinctive behaviors over time, even with continued reinforcement.

Interaction: In factorial designs, when the effect of one independent variable depends on the level of another independent variable.

Internal Stimuli: Stimuli produced by the nervous system and internal organs (thoughts, memories, physiological states) that can trigger emotional responses.

Internal Validity: The extent to which an experiment demonstrates a causal relationship between the IV and DV, free from confounds and alternative explanations.

Interneurons: Neurons in the spinal cord that connect sensory (afferent) and motor (efferent) neurons; the middle component of a reflex arc.

Intervening Variables: Theoretical constructs inferred to exist between observable stimuli and responses, such as hunger, motivation, or learning itself.

Investigatory Reflex: A reflex in which novel or unexpected stimuli elicit inspection and investigatory behaviors.

Kineses: Random movements that continue until favorable conditions are encountered; undirected activity that increases or decreases based on local conditions.

Lashley Jumping Stand: Apparatus developed by Karl Lashley to study discrimination learning; rats jump toward stimulus cards to reach food.

Latent Learning: Learning that occurs without being immediately expressed in performance, demonstrated when the learned behavior becomes useful.

Law of Effect: Thorndike’s principle that responses producing satisfying consequences in a situation become more likely in that situation.

Learning: An inferred change in an organism’s mental state that results from experience and influences what the organism can do.

Learning Curve: A graph showing how performance changes with practice or experience, representing inferences about the learning process.

Learning-Performance Distinction: The recognition that learning (internal capability) and performance (observable behavior) are not the same and don’t always match.

Leg-Flexion Reflex: A protective reflex in which a painful stimulus causes the leg to flex and withdraw from the source of pain.

Levels: The differing amounts or types of an independent variable used in an experiment; also called treatment conditions.

Long-term Potentiation (LTP): The strengthening of synaptic connections between neurons that occurs when they are repeatedly activated together; the neural mechanism underlying learning and memory formation.

Main Effect: In factorial designs, the overall effect of one independent variable, averaged across levels of other independent variables.

Manipulandum: The response device in an operant conditioning chamber, such as a lever for rats to press or a key for pigeons to peck.

Manipulation Check: A measure used to verify that the independent variable manipulation was effective; confirms that the IV actually changed what it was intended to change.

Matched Pairs: A method of creating related groups by measuring participants on some variable before the experiment and pairing similar participants.

Mathematico-Deductive Theory of Behavior: Hull’s formal theory proposing that learning must combine with motivation and other factors for behavior to be exhibited.

Maturation: Behavioral changes that occur due to biological development and aging rather than experience.

Measurement Error: Inaccuracies in measurement; all measurements include truth plus error.

Methodological Determinism: Assuming determinism for research purposes while remaining agnostic about ultimate metaphysical questions of free will.

Method of Authority: A way of fixing belief by accepting ideas because trusted authority figures (experts, teachers, institutions) endorse them; efficient but fails when authorities are wrong.

A Priori Method: A way of fixing belief through pure reasoning, independent of empirical experience; conclusions depend on the quality of premises.

Mimicking CR: A conditioned response that is similar to the UR; the CR resembles what the US produces, as in Pavlov’s experiments where both UR and CR involved salivation.

Moro Reflex: An infant startle reflex in which sudden motion or loud noise causes the arms to extend outward and then return to the body.

Morris Water Maze: Apparatus in which rats swim in opaque water to find a hidden platform; widely used to study spatial learning and hippocampal function.

Motor Skills Apparatus: Equipment such as mirror-tracing apparatus and pursuit rotors used to study motor skill acquisition.

Motivation: A three-step internal process involving activation (energizing behavior), direction (guiding toward a goal), and maintenance (sustaining until goal achievement).

Multiple Independent-Groups Design: A research design with more than two groups of participants formed by random assignment.

Natural Pairs: A method of creating related groups using participants who are naturally related, such as siblings or littermates.

Negative Contingency: A predictive relationship in which the presence of the CS decreases the probability of US occurrence; produces conditioned inhibition.

Negative Phototaxis: Directed movement away from a light source; demonstrated by maggots.

Neurotransmitter: Chemical messengers released from axon terminals into synapses; decreased release during habituation, increased release during sensitization.

Occasion Setting: A phenomenon in which a particular stimulus or environment (the occasion setter) helps retrieve a specific memory; contexts become occasion setters during conditioning, signaling which learning (original conditioning or extinction) is currently relevant.

One-Bottle Test: A method for testing taste aversions that compares consumption of the novel flavor between taste aversion conditioned animals and a control group; conditioned animals drink significantly less, demonstrating the aversion.

One-Way ANOVA: Analysis of Variance for independent groups; a statistical test used when one IV has three or more groups formed by random assignment.

Operant Conditioning: A form of learning in which behavior is modified by its consequences; also called instrumental conditioning.

Operant Conditioning Chamber: Apparatus developed by B.F. Skinner for studying operant conditioning with automated recording and reinforcement delivery; informally called a Skinner box.

Operational Definition: A specification of how a variable is produced and measured in a particular study; defines concepts in terms of specific operations.

Opponent-Process Theory: Solomon’s theory that emotions come in opposing pairs, and when one emotion is experienced, the other is suppressed; repeated presentations change the balance between processes.

Overexpectation Effect: A counterintuitive prediction of the Rescorla-Wagner model in which pairing two fully conditioned CSs together with the same US actually weakens their individual associative strength because the compound produces expectations exceeding the actual US.

Overshadowing: A cue competition effect that occurs when one stimulus in a compound CS is easier to condition and therefore gains more associative strength with the US; the more salient stimulus overshadows the less salient stimulus.

Parsimony: The scientific principle (Occam’s razor) that simpler explanations should be preferred over more complex ones when both account for the data equally well.

Patellar Tendon Reflex: The knee-jerk reflex in which tapping below the kneecap causes the leg to kick forward; a classic example of a simple reflex arc.

Performance: Observable behavior at any given moment; distinguished from learning, which is the internal change in capability.

Physiological Motives: Motives based on biological needs such as hunger, thirst, or sexual arousal.

Pilot Study: A small-scale preliminary study conducted to test methodology rather than hypotheses; used to identify procedural problems before the main experiment.

Positive Contingency: A predictive relationship in which the presence of the CS increases the probability of US occurrence; produces conditioned excitation.

Post hoc Test: A statistical comparison made between group means after finding a significant ANOVA to determine which specific groups differ.

Potentiation: The enhancement of a CS’s ability to elicit a CR by pairing it with another stimulus during conditioning; the opposite of overshadowing, typically occurring in taste aversion learning with odor-taste compounds where taste enhances conditioning to odor.

Prediction: A goal of science involving anticipating when phenomena will occur based on theoretical understanding.

Prediction Error: In the Rescorla-Wagner model, the discrepancy between expected and actual US; positive prediction error (US better than expected) drives excitatory conditioning, while negative prediction error (US worse than expected) produces extinction or inhibition.

Prepared Behaviors: Behaviors that organisms learn so easily and quickly they almost appear instinctive, typically vital to survival or reproduction.

Preparedness: The innate potential to associate certain stimuli more easily and quickly with certain USs; organisms are prepared by evolution to form some associations readily while being unprepared or contraprepared to form others.

Preparedness Continuum: Seligman’s framework categorizing behaviors as prepared, unprepared, or contraprepared based on how biological predispositions affect learning.

Proto-Learning: A term for habituation and sensitization, suggesting they are precursors to true learning rather than learning itself.

Psychological Motives: Motives based on cognitive or social needs rather than biological needs.

Psychic Secretions: Pavlov’s term for salivation that occurred in response to stimuli associated with food, rather than to food itself.

Pupillary Reflex: A reflex in which bright light causes pupil constriction and darkness causes dilation.

Puzzle Box: Apparatus developed by Thorndike to study trial-and-error learning; animals must discover how to escape to reach food.

Quasi-Experiment: A research design resembling a true experiment but lacking random assignment to conditions; can suggest but not definitively establish causal relationships.

Quasi-Learning: A term for habituation and sensitization, suggesting they are learning-like but simpler and shorter-lasting than true learning.

Radial Arm Maze: Apparatus with multiple arms radiating from a central platform; used to study spatial working memory.

Random Assignment: A control technique ensuring each participant has an equal chance of being assigned to any group in the experiment.

Rationalism: The philosophical position that knowledge comes from logical reasoning.

Reaction Chain: A sequence of fixed action patterns where completion of one pattern provides the stimulus for the next.

Receptor Fatigue: The mechanism underlying sensory adaptation, in which sensory receptors become less responsive due to continued stimulation.

Reflex: An innate, automatic, involuntary response elicited by a specific stimulus; the simplest form of behavior.

Reflex Arc: The three-component neural pathway underlying simple reflexes: afferent neurons, interneurons, and efferent neurons.

Reinforcement: The process by which a consequence increases the likelihood of the behavior that produced it.

Related Groups: Groups of research participants that are related through repeated measures, matched pairs, or natural pairs.

Relatively Permanent: A characteristic of learning indicating that true learning creates lasting changes, even though forgetting can occur.

Reliability: The ability to measure the same thing consistently over repeated measurements.

Renewal: The return of an extinguished CR when testing occurs in the original conditioning context after extinction in a different context; demonstrates that extinction learning is context-dependent.

Repeated Measures: A method of creating related groups by testing the same participants in multiple conditions.

Rescorla-Wagner Model: A mathematical theory of classical conditioning in which the strength of conditioning depends on the surprisingness of the US—specifically, when there is a discrepancy between what is expected and what actually occurs; learning is driven by prediction error.

Resistance to Extinction: A measure of conditioning strength based on how many CS-only presentations are required before the CR disappears.

Retardation Tests: A procedure for measuring conditioned inhibition by assessing how slowly a CS- can be converted to a CS+.

Rooting Reflex: An infant reflex in which stimulation of the cheek causes the head to turn toward the stimulus and sucking motions to begin.

Savings: The phenomenon where relearning previously learned material is faster than original learning, indicating lasting neural changes.

Second-Order CS: A stimulus that elicits a CR after being paired with a first-order CS, without ever being paired with the original US.

Sensitive Period: A developmental window when learning is facilitated but not strictly limited to that time; sometimes used interchangeably with critical period.

Sensitization: An increase in the strength of elicited responses resulting from repeated presentation of a stimulus, especially intense or threatening stimuli.

Sensory Adaptation: A decrease in sensation resulting from receptor fatigue due to repeated stimulation; distinguished from habituation by being receptor-based rather than neural.

Sensory Preconditioning: A procedure in which two neutral stimuli are paired before one is conditioned to a US, allowing the other stimulus to also elicit a CR.

Serendipity: An accidental or unexpected discovery in research; finding something valuable while looking for something else (e.g., Pavlov discovering classical conditioning while studying digestion).

Sign Stimulus: A specific stimulus feature that elicits a fixed action pattern; acts like a key that unlocks a specific behavioral program.

Sign Tracking: The tendency to investigate and explore stimuli that predict relevant events; organisms direct attention and behavior toward CSs.

Simultaneous Conditioning: A timing arrangement in which the CS and US occur together at the same time, producing weak conditioning.

Single-Subject Design: An experimental design that intensively studies individual participants through repeated measurement across baseline and treatment phases; also called single-case or N=1 designs.

Single-Trial Learning: Learning that occurs after just one CS-US pairing; characteristic of taste aversion learning where organisms can develop strong aversions from a single experience with illness following food consumption.

Social Learning: Learning that occurs through observing the behavior of others; the acquisition of new behaviors by watching and imitating other individuals rather than through direct experience.

Spontaneous Recovery: The reappearance of a previously extinguished CR after a rest period, demonstrating that extinction does not erase original learning.

S-R Association: Stimulus-Response association in which the CS brain center becomes directly associated with the response center, bypassing the US center; the CS elicits the response directly without activating US representations.

S-S Association: Stimulus-Stimulus association in which the CS brain center becomes associated with the US brain center; when the CS activates its center, activation spreads to the US center, which then produces the response.

Statistical Power: The probability of detecting an effect when one truly exists; related groups designs typically have greater power than independent groups designs.

Statistical Significance: The determination that an observed result is unlikely to have occurred by chance alone.

Stimulus Substitution Theory: Pavlov’s theory proposing that during conditioning, connections form between brain centers such that the CS comes to substitute for the US by activating its neural representation.

Summation Tests: A procedure for measuring conditioned inhibition by presenting a CS- and CS+ together to determine how much the CS- reduces responding.

Synapse: The connection between neurons where neurotransmitters are released; the site of changes underlying habituation and sensitization.

Systematic Desensitization: A behavioral technique based on classical conditioning that treats phobias by combining relaxation training with gradual exposure to phobia-related stimuli; patients progress from least-threatening to more intense exposures.

T-Maze: A simple maze with a single choice point where the animal turns left or right.

t-Test for Independent-Samples: An inferential statistic used to evaluate the difference between two means from randomly assigned groups.

t-Test for Related-Samples: An inferential statistic used to evaluate the difference between two means from related groups; also called paired-samples t-test.

Taste Aversion Learning: A special case of classical conditioning in which consumption of a novel flavor (CS) followed by illness (US) results in avoidance of that flavor (CR); can develop after a single pairing and with delays of many hours between CS and US.

Taxes: Directed movements toward or away from a stimulus source; oriented movement in a specific direction relative to the stimulus.

Theory: A set of interrelated concepts and propositions that present a systematic view of phenomena by specifying relationships among variables.

Tolerance: The phenomenon where repeated drug use requires increasing doses to achieve the same effect; explained by opponent-process theory as strengthening of the b-process; can also be explained by classical conditioning in which contextual cues become CSs that elicit compensatory CRs opposing the drug’s effects.

Trace Conditioning: A timing arrangement in which the CS ends before the US begins, leaving a temporal gap and producing weaker conditioning.

Transfer-Appropriate Processing: The principle that memory performance is best when the processes used during retrieval match those used during encoding.

Tropism: A whole-body movement forced by a particular stimulus; the organism moves mechanistically toward or away from the stimulus.

Tukey’s HSD: Honestly Significant Difference; a commonly used post hoc test that controls for multiple comparisons.

Two Independent-Groups Design: A research design with two groups of participants formed by random assignment.

Two Related-Groups Design: A research design with two groups of participants formed using repeated measures, matched pairs, or natural pairs.

Two-Bottle Test: A method for testing taste aversions useful for detecting weak aversions; thirsty animals choose between a familiar flavor and the novel flavor, with conditioned animals drinking significantly less of the novel flavor.

Unconditioned Reflex: An innate stimulus-response connection that does not require learning.

Unconditioned Response (UR): The unlearned, naturally occurring response to an unconditioned stimulus.

Unconditioned Stimulus (US): A stimulus that naturally and automatically triggers a response without prior learning.

Unprepared Behaviors: Behaviors that organisms can learn but only with moderate effort and repeated practice; most typical learning falls in this category.

Validity: The ability to measure the construct you intended to measure.

Verbal Learning Equipment: Apparatus such as memory drums used to study human memory, often with nonsense syllables as stimuli.

Withdrawal Symptoms: Intense negative states experienced when a drug wears off; result from the strengthened b-process no longer balanced by the drug’s effects.

Within-Subjects Factor: An independent variable for which the same participants experience all levels; also called repeated measures factor.

Working Memory: The cognitive system responsible for temporarily holding and manipulating information; tested by radial arm maze performance.

Y-Maze: A maze with three arms radiating from a central choice point.

Zero Contingency: A predictive relationship in which the CS provides no information about US occurrence; no conditioning occurs.