Psychology Glossary

Acculturation is the process of psychological and social change that an individual or group undergoes as a result of prolonged contact with a different culture — typical, for example, among migrants. Psychologist John Berry identified four acculturation strategies: integration (maintaining one’s own identity while being open to the new culture), assimilation (abandoning the original identity in favor of the new one), separation (holding on exclusively to the culture of origin), and marginalization (rejecting both cultures). The chosen strategy has a significant impact on psychological well-being.

Affect is a broad term referring to the subjective experience of emotion — encompassing both momentary emotional reactions to a specific event and a more diffuse, longer-lasting mood. In clinical psychology, a distinction is made between normal affect, flat affect (diminished emotional expression), inappropriate affect (incongruent with the situation), and labile affect (rapidly and dramatically shifting). Assessing affect is one of the basic elements of a mental status examination.

Aggression is behavior directed at causing harm or injury to another person, oneself, or one’s surroundings, against that person’s will. Psychologists distinguish reactive aggression (a response to provocation or frustration) from instrumental aggression (a means to achieve another goal, such as dominance or gain), as well as physical, verbal, and relational aggression (such as excluding someone from a group). Research on aggression covers both biological factors and the influence of social learning and environment.

Ambivalence is a state of simultaneously experiencing two opposing emotions, attitudes, or desires toward the same object, person, or situation — for example, love and anger toward a close person, or a desire for change together with fear of it. Ambivalence is a natural part of many important life decisions and relationships, but its intensified or chronic form can become a source of significant psychological tension and difficulty making decisions.

Amnesia is a memory disorder involving a partial or total inability to recall information from the past (retrograde amnesia) or to store new information after the onset of the disorder (anterograde amnesia). Causes of amnesia can be organic (head injury, stroke, neurodegenerative disease) or psychogenic, related to severe stress or psychological trauma. Amnesia is studied in both neuropsychology and clinical psychology.

Anorexia nervosa is an eating disorder characterized by persistent restriction of energy intake leading to significantly low body weight, an intense fear of gaining weight even when underweight, and a disturbance in how one’s body weight or shape is experienced. It has one of the highest mortality rates among psychiatric disorders and typically requires a coordinated treatment approach involving medical monitoring, nutritional rehabilitation, and psychotherapy.

Antisocial personality disorder is characterized by a pervasive pattern of disregard for and violation of the rights of others, beginning by age 15 and continuing into adulthood. Features often include deceitfulness, impulsivity, irritability and aggressiveness, disregard for the safety of oneself or others, and a lack of remorse. It is related to, but distinct from, the concept of psychopathy, and is more common in men than in women.

Assertiveness is the ability to openly and directly express one’s own thoughts, needs, opinions, and boundaries, while respecting the rights and boundaries of others. It represents a middle ground between a submissive attitude (subordinating one’s own needs to those of others) and an aggressive attitude (pursuing one’s own needs at others’ expense). Assertiveness can be learned — assertiveness training is one of the most commonly used forms of support for developing social competence.

Attachment theory, developed by John Bowlby and expanded by Mary Ainsworth, describes how a child’s early relationship with a caregiver shapes patterns of emotional bonding later used in adult relationships. Attachment styles include: secure, anxious-ambivalent, avoidant, and disorganized. Attachment style influences how a person regulates emotions, builds closeness, and responds to stress in relationships.

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition involving a persistent pattern of inattention (such as difficulty sustaining focus or organizing tasks) and/or hyperactivity-impulsivity (such as restlessness or acting without thinking) that is inconsistent with a person’s developmental level and interferes with functioning at school, work, or in relationships. Treatment often combines behavioral strategies, environmental accommodations, and, in many cases, medication.

Attribution error refers to systematic irregularities in the way people explain the causes of behavior — their own and others’. The best-known example is the fundamental attribution error: the tendency to explain other people’s behavior by their character traits (“they were late because they’re irresponsible”), while explaining one’s own behavior by situational factors (“I was late because I got stuck in traffic”). The phenomenon was described by psychologist Lee Ross, and understanding it is highly relevant in social psychology and in therapeutic work on relationships.

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by differences in social communication and interaction, along with restricted or repetitive behaviors, interests, or activities, and often heightened or diminished sensitivity to sensory input. It is described as a “spectrum” because its presentation and level of support needs vary widely from person to person. ASD is typically identified in early childhood, though some individuals are diagnosed later in life.

Autonomy is a psychological need related to the sense that one’s actions are the result of free choice rather than external pressure or coercion. In Edward Deci and Richard Ryan’s self-determination theory, autonomy, alongside competence and relatedness, is one of three basic psychological needs whose satisfaction underlies well-being and intrinsic motivation. A sense of autonomy develops from early childhood and is important both in upbringing and in the workplace.

The Big Five model describes personality using five broad, relatively independent dimensions: openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism (often remembered by the acronym OCEAN). Each dimension represents a continuum along which individuals can be placed, rather than a fixed type. The model is one of the most extensively validated frameworks in personality psychology and underlies many widely used personality questionnaires.

Bipolar disorder is characterized by episodes of depression alternating with episodes of mania (a period of abnormally elevated mood, energy, and activity) or the milder hypomania. During manic episodes, a person may experience decreased need for sleep, grandiosity, rapid speech, and impulsive or risky behavior. Bipolar disorder is typically managed with mood-stabilizing medication alongside psychotherapy and lifestyle strategies to maintain stable routines.

Borderline personality disorder (BPD) is characterized by a pervasive pattern of instability in emotional regulation, self-image, and interpersonal relationships, along with marked impulsivity. People with BPD often experience intense emotional reactions, a strong fear of abandonment, and rapidly shifting views of themselves and others. Dialectical behavior therapy, developed specifically for BPD, has strong evidence supporting its effectiveness.

Burnout is a syndrome resulting from prolonged, unmanaged work-related stress. It includes three main components: emotional exhaustion, depersonalization (a cynical distance toward one’s duties and other people), and a reduced sense of professional efficacy. The World Health Organization classifies burnout as an occupational phenomenon requiring proper diagnosis and intervention.

The bystander effect refers to the finding that people are often less likely to offer help in an emergency when other bystanders are present, compared to when they are alone. Proposed explanations include diffusion of responsibility (assuming someone else will act) and social influence (looking to others’ reactions to judge whether a situation is truly an emergency). The phenomenon, studied extensively after the case of Kitty Genovese, has informed research on prosocial behavior and emergency intervention training.

Catharsis refers to the emotional release that can occur when a person expresses, relives, or processes strong pent-up feelings — such as grief, anger, or fear — often within a supportive or therapeutic context. The concept originates in Aristotle’s writing on tragedy and was later adapted by Freud and Breuer in early psychoanalytic theory, who proposed that symptoms could be relieved by bringing repressed emotions into conscious awareness and expression. Contemporary research suggests the emotional benefits of catharsis are more nuanced than originally proposed, depending heavily on how and in what context the emotion is expressed.

Classical conditioning is a form of learning described by Ivan Pavlov, in which a neutral stimulus (such as the sound of a bell) begins to trigger a response through repeated association with an unconditioned stimulus (such as food) that naturally produces that response. This mechanism explains the formation of many emotional habits, including some fears and phobias, and underlies many behavioral therapy techniques.

Codependency describes a pattern of relating in which a person’s sense of identity and self-worth becomes excessively tied to caretaking for, or managing the problems of, another person — often a partner or family member struggling with addiction or another compulsive behavior. Codependent patterns often involve difficulty setting boundaries, excessive self-sacrifice, and a need to be needed. While not a formal clinical diagnosis, the concept is widely used in addiction treatment and family therapy.

Cognitive behavioral therapy (CBT) is a therapeutic approach based on the premise that the way a person thinks about a situation influences their emotions and behavior. Therapeutic work focuses on identifying and modifying cognitive distortions and unhelpful behavioral patterns, often using specific techniques and between-session assignments. CBT is among the approaches with the strongest documented scientific effectiveness, including in the treatment of depression, anxiety disorders, and phobias.

Piaget’s theory of cognitive development proposes that children progress through four qualitatively distinct stages of thinking: sensorimotor, preoperational, concrete operational, and formal operational. At each stage, children construct increasingly sophisticated mental structures for understanding the world, moving from action-based knowledge in infancy to abstract, hypothetical reasoning in adolescence. Although later research has refined and challenged aspects of Piaget’s timeline, the theory remains foundational in developmental psychology and education.

Cognitive dissonance is a state of mental discomfort that occurs when a person simultaneously holds two contradictory beliefs, or when their behavior contradicts their values. The concept was introduced by Leon Festinger in 1957. To reduce this tension, people often change their beliefs, rationalize their behavior, or avoid information that would deepen the contradiction — which has important implications in the psychology of decision-making, marketing, and attitude research.

Confirmation bias is a pervasive cognitive bias in which people favor information that supports what they already believe, while ignoring or discounting contradictory evidence. It affects everyday reasoning, scientific interpretation, and decision-making, and helps explain why beliefs — including mistaken ones — can be so resistant to correction, even in the face of strong counter-evidence.

The distinction between correlation and causation is a fundamental methodological principle in psychological research: even when two variables are strongly and consistently associated, that association alone does not establish that one causes the other. The relationship could instead be explained by a third, confounding variable, by reverse causation, or by chance. Establishing causation typically requires carefully controlled experimental designs, such as randomized controlled trials.

Defense mechanisms are a concept originating from Sigmund Freud’s psychoanalysis, later developed by Anna Freud, describing unconscious ways of coping with anxiety, internal conflict, or threatening reality. The most commonly described include repression, denial, rationalization, projection, and sublimation. Although they serve a protective function, excessive or rigid reliance on certain defense mechanisms can hinder healthy coping with reality.

Dialectical behavior therapy (DBT), developed by Marsha Linehan, was originally designed to treat borderline personality disorder and chronic suicidality, and has since been adapted for other conditions involving emotional dysregulation. It combines cognitive-behavioral techniques with practices drawn from mindfulness, balancing strategies for accepting oneself as one is with strategies for making meaningful change. DBT typically includes individual therapy, skills training groups, and between-session coaching.

The Dunning–Kruger effect is a cognitive bias described in 1999 by David Dunning and Justin Kruger, in which people with a low level of competence in a given field tend to overestimate their skills — because they lack the knowledge needed to accurately assess their own shortcomings. This phenomenon is sometimes contrasted with “impostor syndrome,” in which highly competent people underestimate their abilities.

Emotional intelligence is the ability to accurately recognize one’s own and others’ emotions, understand their causes, and manage them adaptively. The concept was popularized by Daniel Goleman, building on earlier work by Peter Salovey and John Mayer. High emotional intelligence is associated with better relationship quality, more effective stress management, and greater satisfaction in professional and personal life.

Emotional regulation refers to the strategies people use — consciously or automatically — to influence the emotions they experience, when they experience them, and how they express them. Strategies range from adaptive approaches, such as reappraising a situation or seeking social support, to less adaptive ones, such as suppression or avoidance. Difficulties with emotional regulation are implicated in a wide range of mental health conditions, and building more effective regulation skills is a common goal across many forms of psychotherapy.

Empathy is the ability to recognize, understand, and share the emotions of another person. Psychologists distinguish between cognitive empathy (understanding another person’s perspective) and affective empathy (sharing their emotional state). Empathy plays a key role in building relationships, communication, and therapeutic work, and its deficits are often studied in the context of personality disorders.

Executive functions are a group of cognitive processes — including working memory, inhibitory control, and cognitive flexibility — that allow a person to plan, focus attention, resist impulses, and adapt to changing demands. These functions rely heavily on the prefrontal cortex and continue developing into early adulthood. Executive function difficulties are central to conditions such as ADHD and are also affected by chronic stress and sleep deprivation.

Exposure therapy is a behavioral technique in which a person is gradually and systematically exposed to a feared stimulus — such as a phobic object, a traumatic memory, or an anxiety-provoking situation — in a safe and controlled way, allowing anxiety to naturally decrease over repeated exposures. It is a core component of treatment for phobias, panic disorder, obsessive-compulsive disorder, and post-traumatic stress disorder, and can be conducted gradually (systematic desensitization) or more intensively (flooding).

Extraversion is one of the five dimensions of personality in the Big Five model. People high in extraversion tend to be sociable, active, seek stimulation, and experience positive emotions in the company of others. The opposite of extraversion is introversion, associated with a preference for solitude and a lower need for external stimulation. This dimension is measured by tests such as the NEO-FFI and the B5T.

Extrinsic motivation involves performing an activity as a means to an end — to earn a reward, gain approval, or avoid punishment — rather than because of interest in the activity itself. It can range from fully external control (such as working solely for a paycheck) to more internalized forms, where a person accepts an external goal as personally meaningful. Extrinsic motivation is not inherently harmful, but research suggests that excessive reliance on external rewards can sometimes undermine intrinsic motivation for an activity.

Flow, a concept developed by Mihaly Csikszentmihalyi, describes a state of deep, effortless engagement in an activity, characterized by intense focus, a merging of action and awareness, and a distorted sense of time. Flow tends to occur when the challenge of a task closely matches a person’s skill level — not so easy that it induces boredom, nor so difficult that it induces anxiety. The concept has been influential in positive psychology, education, and the study of peak performance.

The distinction between fluid and crystallized intelligence, proposed by Raymond Cattell, separates two broad components of cognitive ability. Fluid intelligence refers to the capacity to reason, identify patterns, and solve novel problems independent of acquired knowledge, and tends to peak in early adulthood before gradually declining. Crystallized intelligence refers to accumulated knowledge, vocabulary, and skills gained through experience and education, and tends to remain stable or even increase well into later adulthood.

Gaslighting refers to a pattern of manipulative behavior in which one person causes another to question their own memory, perception, or sanity, typically through persistent denial, contradiction, and misdirection. Over time, this can erode the targeted person’s confidence in their own judgment and increase dependence on the manipulator’s version of reality. The term originates from a 1938 stage play (and later films) in which a husband manipulates his wife into believing she is losing her mind.

Generalized anxiety disorder is characterized by chronic, excessive worry about many everyday matters (work, health, finances, relationships) that persists on most days for at least six months and is difficult to control. It is usually accompanied by symptoms such as muscle tension, sleep problems, irritability, and difficulty concentrating. Treatment usually combines psychotherapy, most often cognitive behavioral therapy, with possible pharmacological support.

Groupthink, a term coined by psychologist Irving Janis, describes a mode of thinking that occurs in highly cohesive groups when the desire for agreement and harmony overrides a realistic appraisal of alternative courses of action. Symptoms include an illusion of invulnerability, suppression of dissenting opinions, and pressure on members to conform. Groupthink has been used to analyze several historical decision-making failures and highlights the importance of encouraging dissent and critical evaluation within groups.

Growth mindset, a concept developed by Carol Dweck, refers to the belief that abilities and intelligence can be developed over time through effort, strategy, and learning from mistakes, in contrast to a “fixed mindset,” which views abilities as largely innate and unchangeable. People with a growth mindset tend to respond to setbacks and challenges with greater persistence, since difficulty is interpreted as an opportunity to learn rather than as evidence of a fixed limitation. The concept has had a significant influence on educational practice.

The halo effect is a cognitive bias in which an overall positive (or negative) impression of a person influences the assessment of their specific, unrelated traits — for example, a person perceived as physically attractive is often automatically judged to be more competent or honest. The phenomenon was described by psychologist Edward Thorndike in 1920. The halo effect is significant in recruitment processes, teacher evaluations, and research on first impressions.

Maslow’s hierarchy of needs proposes that human motivation is organized into a series of levels, typically depicted as a pyramid: physiological needs, safety, love and belonging, esteem, and, at the top, self-actualization. According to the theory, lower-level needs generally must be reasonably satisfied before higher-level needs become motivating. While later research has questioned the strict order Maslow proposed, the theory remains influential in psychology, education, and management.

Humanistic psychology emerged in the mid-20th century, associated with figures such as Carl Rogers and Abraham Maslow, as an alternative to both psychoanalysis and behaviorism. It emphasizes personal agency, subjective experience, and each individual’s inherent drive toward growth and self-actualization, viewing people as fundamentally striving toward positive development when given the right conditions. Its influence is visible in person-centered therapy and much of positive psychology.

Impostor syndrome refers to a pattern of persistent self-doubt in which a person, despite clear evidence of their competence and accomplishments, feels like a fraud and fears being “found out.” It often coexists with high achievement and is linked to attributing success to luck or external factors rather than one’s own ability. Though not a formal clinical diagnosis, the concept has become widely recognized in discussions of workplace psychology and academic life.

Insomnia is characterized by persistent difficulty initiating or maintaining sleep, or sleep that is non-restorative, occurring despite adequate opportunity for sleep and leading to daytime consequences such as fatigue, mood disturbance, and impaired concentration. It can be a standalone condition or occur alongside other physical or mental health conditions. Cognitive behavioral therapy for insomnia (CBT-I) is considered a first-line treatment, often more effective in the long term than medication alone.

The intelligence quotient (IQ) is a score derived from standardized tests designed to measure general cognitive ability — including reasoning, problem-solving, and verbal and spatial skills — relative to a representative sample of same-age peers, with scores typically scaled to a mean of 100. While IQ scores are strong predictors of certain academic and occupational outcomes, they capture only part of what is meant by “intelligence” and do not account for creativity, practical skill, or emotional and social competence.

Intrinsic motivation refers to doing something because it is inherently interesting, enjoyable, or satisfying, rather than to obtain an external reward or avoid punishment. It is central to self-determination theory, which links intrinsic motivation to the satisfaction of the needs for autonomy, competence, and relatedness. Activities driven by intrinsic motivation tend to be sustained longer and associated with deeper learning and greater well-being than those driven purely by external rewards.

Learned helplessness is a state of reduced motivation to act, resulting from repeated experiences in which efforts had no impact on the outcome of a situation. The phenomenon was described by Martin Seligman and Steven Maier in experiments in the late 1960s. Learned helplessness is often linked to the development of depression and helps explain why some people stop trying to change a difficult situation, even when a real opportunity for change appears.

Locus of control, a concept developed by Julian Rotter, describes the degree to which people believe they can control the events that affect them. Those with an internal locus of control tend to attribute outcomes to their own effort and decisions, while those with an external locus of control attribute them to luck, fate, or other people. An internal locus of control is generally associated with greater persistence, better stress management, and higher academic and occupational achievement.

Major depressive disorder is characterized by a persistently depressed mood or loss of interest and pleasure in most activities, lasting at least two weeks, along with symptoms such as changes in sleep and appetite, fatigue, difficulty concentrating, feelings of worthlessness, and, in severe cases, thoughts of death or suicide. It is one of the most common mental health conditions worldwide and is typically treated with psychotherapy, medication, or a combination of both.

Mindfulness refers to the practice of intentionally focusing attention on the present moment — thoughts, bodily sensations, and surroundings — with an attitude of openness and non-judgment, rather than automatically reacting or ruminating. Rooted in contemplative traditions and adapted for clinical use by researchers such as Jon Kabat-Zinn, mindfulness-based interventions have accumulated substantial evidence for reducing stress, anxiety, and the risk of depressive relapse.

Narcissistic personality disorder involves a long-standing pattern of grandiosity (in fantasy or behavior), an excessive need for admiration, and a lack of empathy for others, often masking underlying vulnerability and sensitivity to criticism. It is distinct from ordinary self-confidence or occasional self-centered behavior, and is diagnosed only when the pattern is pervasive, inflexible, and causes significant impairment in relationships or functioning.

Neuroplasticity is the brain’s ability to reorganize neural connections in response to experience, learning, or injury. It includes changes at the level of individual synapses as well as larger brain structures. This phenomenon underlies learning, memory, and rehabilitation processes after neurological injury, and also supports the effectiveness of many forms of psychological therapy.

Norm-referenced testing interprets an individual’s test performance by comparing it to the performance of a representative “norm group” who previously took the same test, rather than to a fixed, predetermined standard. This allows a person’s score to be expressed in relative terms — such as a percentile rank — showing how they performed compared to others of a similar age or background. Most standardized intelligence and personality tests are norm-referenced.

Obsessive-compulsive disorder (OCD) involves recurrent, intrusive thoughts, urges, or images (obsessions) that cause significant anxiety, along with repetitive behaviors or mental acts (compulsions) performed to neutralize that anxiety or prevent a feared outcome. Common themes include contamination, symmetry, and harm. While the compulsions temporarily reduce distress, they reinforce the cycle over time. Exposure and response prevention, a form of cognitive behavioral therapy, is considered a first-line treatment.

Operant conditioning, described by B. F. Skinner, is a form of learning in which the likelihood of a behavior increases or decreases depending on the consequences that follow it. Reinforcement (positive or negative) strengthens a behavior, while punishment weakens it. Unlike classical conditioning, which pairs two stimuli, operant conditioning links a behavior to its outcome, and it underlies much of everyday learning, habit formation, and behavior modification techniques.

Panic disorder involves recurrent, unexpected panic attacks — sudden surges of intense fear accompanied by physical symptoms such as a racing heart, shortness of breath, dizziness, and a feeling of impending doom — along with persistent worry about future attacks or their consequences. This worry often leads to avoidance of situations associated with previous attacks. Treatment typically combines cognitive behavioral therapy with, in some cases, medication.

Person-centered therapy, developed by Carl Rogers, is based on the idea that people have an inherent capacity for growth that can be unlocked by a therapeutic relationship characterized by three core conditions: empathy, unconditional positive regard, and congruence (genuineness) on the part of the therapist. Rather than directing the client toward specific solutions, the therapist provides a supportive, non-judgmental space for the client to explore their own thoughts and feelings. This approach has strongly influenced counseling practice across many therapeutic orientations.

The placebo effect refers to a genuine, measurable improvement in a person’s symptoms following an inert or sham treatment, arising from the person’s expectations, the therapeutic relationship, and other psychological and neurobiological factors rather than any active ingredient. It is a central methodological consideration in clinical research, which is why treatments are often tested against a placebo condition in randomized, controlled trials to isolate the treatment’s true effect.

Post-traumatic stress disorder (PTSD) can develop after experiencing or witnessing a traumatic event such as violence, an accident, or a natural disaster. Core symptoms include intrusive memories or flashbacks, avoidance of trauma-related reminders, negative changes in mood and thinking, and heightened arousal (such as hypervigilance or an exaggerated startle response). Effective treatments include trauma-focused cognitive behavioral therapy and eye movement desensitization and reprocessing (EMDR).

Psychodynamic therapy, rooted in and expanded from Freud’s psychoanalysis, explores how unconscious mental processes, early relationships, and unresolved past experiences shape present-day thoughts, emotions, and behavior. Therapeutic work often focuses on patterns that repeat across relationships, including the relationship with the therapist, and aims to build insight into these patterns rather than focusing primarily on symptom reduction alone. Modern psychodynamic therapy is typically shorter and more structured than classical psychoanalysis.

Psychological adaptation is the process by which an individual adjusts their thinking, emotions, and behavior to new or changing environmental conditions — such as a change of residence, illness, the loss of a loved one, or a new life role. Successful adaptation involves cognitive and emotional flexibility, as well as the ability to draw on available internal resources and external support. Difficulties with adaptation can lead to chronic stress and adjustment-related disorders.

Resilience is the psychological ability to maintain or regain mental well-being despite difficult, stressful, or traumatic experiences. It is not a fixed trait but a process shaped by individual factors (such as a sense of agency and cognitive flexibility) and environmental factors (social support, secure relationships). Resilience can be developed through appropriate psychological interventions.

Sampling bias occurs when the individuals included in a study are not representative of the broader population the researcher intends to draw conclusions about, often because of how participants were recruited or who was willing or able to take part. This can distort a study’s findings and limit how far its results can be generalized. Researchers use techniques such as random sampling and careful recruitment strategies to minimize this risk.

Schizophrenia is a chronic psychiatric disorder characterized by “positive” symptoms such as hallucinations (most commonly hearing voices) and delusions (fixed false beliefs), as well as “negative” symptoms such as reduced emotional expression and motivation, and cognitive difficulties with attention and memory. Onset is typically in late adolescence or early adulthood. Treatment usually involves antipsychotic medication combined with psychosocial support and rehabilitation.

Self-determination theory, developed by Edward Deci and Richard Ryan, proposes that human motivation and well-being depend on the satisfaction of three basic psychological needs: autonomy (a sense of choice and volition), competence (feeling effective and capable), and relatedness (feeling connected to others). When these needs are supported, people tend to experience more intrinsic motivation, better mental health, and greater engagement in their activities; when the needs are thwarted, motivation and well-being tend to suffer.

Self-efficacy, a concept introduced by Albert Bandura, refers to a person’s belief in their own ability to successfully execute the behaviors needed to achieve a specific goal or accomplish a particular task. It is distinct from general self-esteem, since a person can have high self-efficacy in one domain (such as public speaking) and low self-efficacy in another (such as mathematics). Higher self-efficacy is associated with greater persistence, resilience in the face of setbacks, and willingness to attempt challenging tasks.

Self-esteem is a subjective, evaluative judgment of oneself, encompassing both beliefs about oneself and the emotions associated with them (pride, shame, self-worth). High, well-founded self-esteem is associated with better coping with stress and life’s difficulties, while extremely low or unrealistically high self-esteem is often linked to emotional difficulties and relationship problems.

Social loafing describes the reduction in individual effort that often occurs when people work collectively toward a shared goal, compared to when they are individually accountable. The phenomenon is more pronounced when individual contributions are not identifiable and when the task is perceived as less personally meaningful. Social loafing has important implications for team design, group work in education, and organizational management.

Standard deviation is a statistic that quantifies the amount of variation or spread in a set of scores around their mean. A small standard deviation indicates that scores tend to cluster closely around the average, while a large standard deviation indicates greater variability. In psychological testing, standard deviation is essential for interpreting where an individual’s score falls relative to others and underlies many standardized scoring systems, such as IQ scores.

A stereotype is a simplified, strongly generalized belief about the traits, behaviors, or values attributed to all members of a given social group, regardless of individual differences. Stereotypes serve as a cognitive “shortcut” that helps people quickly navigate a complex social world, but they can become a source of prejudice and discrimination when applied rigidly and never checked against reality.

Temperament is a set of relatively stable, largely innate traits that determine a person’s style of emotional reactivity, energy level, and regulation of arousal. Unlike personality, which is also shaped by experience and learning, temperament has a stronger biological basis and appears from early childhood. Research on temperament includes the work of Jan Strelau, as well as the classical division into temperament types dating back to the traditions of Hippocrates and Galen.

Test reliability is one of the fundamental psychometric properties of a research tool, indicating the degree to which a measurement is free of random error — that is, how consistent and repeatable the test’s results are. It is assessed, among other methods, through the test-retest method (re-testing the same person after some time), the split-half method, or Cronbach’s alpha, which measures the internal consistency of test items. High reliability is a necessary, though not sufficient, condition for good test validity.

Test validity is a psychometric property indicating the extent to which a research tool actually measures the psychological construct it was designed to measure, rather than something else. It includes content validity (whether test items reflect the full scope of the phenomenon studied), criterion validity (agreement of results with another external indicator), and construct validity (agreement with the theoretical assumptions on which the tool is based). A test can be reliable without necessarily being valid — which is why both properties are examined together.

Theory of mind is the cognitive capacity to understand that other people have their own beliefs, desires, and intentions, which may differ from one’s own and from reality. It typically develops through early childhood and is often assessed using “false-belief” tasks. Difficulties with theory of mind have been studied extensively in autism spectrum disorder, though the relationship is complex and not universal across the spectrum.

Transactional analysis is a psychotherapeutic concept created by Eric Berne, describing personality and interpersonal relationships through three ego states: the Parent (beliefs and norms adopted from caregivers), the Adult (a rational assessment of “here and now” reality), and the Child (emotions and reactions from childhood). Analyzing the “transactions” — communicative exchanges between these states in different people — helps to understand recurring relational patterns and conflicts, and therapeutic work focuses on increasing the role of the Adult state in daily functioning.

Working memory is a limited-capacity system that allows a person to hold information in mind and actively work with it — for example, while solving a math problem or following a conversation. Alan Baddeley’s influential model divides working memory into components handling verbal and visual-spatial information, coordinated by a central executive. Working memory capacity is closely linked to reasoning, reading comprehension, and academic performance.

The zone of proximal development, a concept introduced by Lev Vygotsky, refers to the range of tasks a learner cannot yet perform alone but can accomplish with the support of a teacher, parent, or more skilled peer. This concept underlies the idea of “scaffolding” in education — providing temporary support that is gradually withdrawn as the learner becomes more capable. It emphasizes the social and collaborative nature of learning and development.