List of essential psychology terms and their definitions:

 List of essential psychology terms and their definitions:

​Clinical & Personality Terms

• ​Id: The part of the psyche that houses primitive drives and instinctual needs.
• ​Ego: The rational part of the mind that balances the Id and reality.
• ​Superego: The internal "moral compass" or conscience.
• ​Defense Mechanism: An unconscious mental process used to avoid anxiety or conflict.
• ​Psychosis: A mental state characterized by a loss of contact with reality.
• ​Neurosis: A distressed mental state that does not involve a loss of contact with reality (e.g., chronic anxiety).

​Cognitive & Behavioral Terms

• ​Cognition: The mental process of knowing, including aspects such as awareness, perception, and reasoning.
• ​Conditioning: A process where a specific behavior is learned through association or consequences.
• ​Cognitive Dissonance: The mental tension felt when holding two conflicting beliefs simultaneously.
• ​Schema: A mental framework that helps organize and interpret information.
• ​Heuristic: A mental shortcut or "rule of thumb" used to make quick decisions.

​Social & Developmental Terms

• ​Empathy: The ability to understand and share the feelings of another person.
• ​Attachment: The deep emotional bond between two people, usually a child and caregiver.
• ​Social Loafing: The tendency for individuals to put in less effort when working in a group than when alone.
• ​Self-Efficacy: An individual's belief in their capacity to execute behaviors necessary to produce specific performance attainments.
• ​Intrinsic Motivation: Doing an activity for its inherent satisfaction rather than for some separable consequence.

​Biological Terms

• ​Neurotransmitter: A chemical messenger that carries signals between brain cells (neurons).
• ​Plasticity: The brain's ability to change and adapt as a result of experience.
• ​Amydgala: The part of the brain primarily involved in processing emotions, especially fear.

Behavioral & Learning Terms

• ​Habituation: A decrease in response to a stimulus after repeated presentations.
• ​Extinction: The gradual weakening and disappearance of a conditioned response.
• ​Reinforcement: Any event that strengthens or increases the behavior it follows.
• ​Punishment: Any change in a human or animal's surroundings that occurs after a given behavior or response which reduces the likelihood of that behavior occurring again in the future.
• ​Generalization: The tendency to respond in the same way to different but similar stimuli.

​Cognitive & Memory Terms

• ​Encoding: The initial learning of information by placing it into memory storage.
• ​Retrieval: The process of accessing and bringing into consciousness information from memory storage.
• ​Executive Function: A set of cognitive processes (including working memory and flexible thinking) that help us plan and achieve goals.
• ​Confirmation Bias: The tendency to search for, interpret, and favor information that confirms one's pre-existing beliefs.
• ​Working Memory: A system for temporarily storing and managing the information required to carry out complex cognitive tasks like learning and reasoning.

​Developmental & Social Terms

• ​Self-Concept: The total collection of beliefs that an individual holds about their own personal attributes.
• ​Locus of Control: The degree to which people believe that they, as opposed to external forces, have control over the outcome of events in their lives.
• ​Bystander Effect: A social phenomenon where individuals are less likely to offer help to a victim when other people are present.
• ​Groupthink: A psychological phenomenon that occurs within a group of people in which the desire for harmony or conformity results in an irrational or dysfunctional decision-making outcome.
• ​Attachment Style: The specific way an individual relates to others in relationships (e.g., Secure, Anxious, Avoidant).

​Biological & Sensory Terms

• ​Synapse: The small gap between two neurons where nerve impulses are relayed by a neurotransmitter.
• ​Homeostasis: The tendency of a system to maintain internal stability and balance.
• ​Perception: The process of organizing and interpreting sensory information to recognize meaningful objects and events.
• ​Threshold: The minimum level of stimulation required to trigger a neural impulse or a sensory experience.
• ​Circadian Rhythm: The natural, internal process that regulates the sleep-wake cycle and repeats roughly every 24 hours.

​Research & Measurement Terms

• ​Variable: Any factor, trait, or condition that can exist in differing amounts or types.
• ​Hypothesis: A testable prediction about the relationship between two or more variables.
• ​Correlation: A statistical measure that describes the size and direction of a relationship between two variables.
• ​Control Group: The participants in an experiment who do not receive the treatment, used as a benchmark for comparison.
• ​Validity: The extent to which a test or experiment measures what it claims to measure.
• ​Reliability: The consistency of a research study or measuring test.

​Abnormal Psychology & Therapy

• ​Phobia: An extreme or irrational fear of or aversion to something.
• ​Mania: A state of abnormally elevated energy levels, mood, or irritability.
• ​Delusion: A persistent false belief maintained despite contradictory evidence.
• ​Hallucination: A sensory experience (like seeing or hearing things) that appears real but is created by the mind.
• ​Transference: A phenomenon in therapy where a patient redirects feelings for others onto the therapist.
• ​Catharsis: The process of releasing, and thereby providing relief from, strong or repressed emotions.

​Social & Cognitive Phenomena

• ​Fundamental Attribution Error: The tendency to overemphasize personal traits and underestimate situational factors when judging others' behavior.
• ​Halo Effect: A cognitive bias where our overall impression of a person influences how we feel and think about their character in specific areas.
• ​In-group Bias: The tendency to favor one’s own group over "out-groups."
• ​Self-Serving Bias: The habit of taking credit for positive events but blaming external factors for negative ones.
• ​Stereotype Threat: A situational predicament in which people are or feel themselves to be at risk of conforming to stereotypes about their social group.

​Sensory & Perceptual Terms

• ​Absolute Threshold: The lowest level of a stimulus (light, sound, touch) that an organism can detect.
• ​Selective Attention: The process of focusing on a particular object in the environment for a certain period of time while ignoring irrelevant information.
• ​Sensory Adaptation: A reduction in sensitivity to a stimulus after constant exposure to it (e.g., getting used to a cold pool).
• ​Top-Down Processing: Brain-to-sensory processing where we form perceptions based on our existing knowledge and expectations.
• ​Bottom-Up Processing: Sensory-to-brain processing where we build a perception from the individual bits of raw sensory data.

Learning & Motivational Terms

• ​Observational Learning: Learning that occurs through observing the behavior of others.
• ​Learned Helplessness: A state that occurs after a person has experienced a stressful situation repeatedly, leading them to believe they are unable to control or change the situation.
• ​Overjustification Effect: A phenomenon in which being rewarded for doing something actually diminishes intrinsic motivation to perform that action.
• ​Approach-Avoidance Conflict: A situation involving a choice that has both positive and negative consequences.
• ​Flow: A state of complete immersion and focus in an activity where time seems to disappear.

​Developmental & Personality Theory

• ​Conservation: The understanding that changing the form of a substance or object does not change its amount, overall volume, or mass (a key milestone in child development).
• ​Object Permanence: The understanding that objects continue to exist even when they cannot be seen, heard, or otherwise sensed.
• ​Egocentrism: The inability on the part of a child in the early stages of development to see any point of view other than their own.
• ​Projection: A defense mechanism where individuals attribute their own unacceptable thoughts or feelings to another person.
• ​Sublimation: A defense mechanism where socially unacceptable impulses are transformed into socially acceptable actions or behavior.

​Perception & Biological Terms

• ​Limbic System: A complex system of nerves and networks in the brain, involving the instinct and mood. It controls basic emotions and drives.
• ​Signal Detection Theory: A means to measure the ability to differentiate between information-bearing patterns and random patterns that distract from the information (noise).
• ​Binocular Cues: Visual information taken in by two eyes that enable us a sense of depth (e.g., retinal disparity).
• ​Weber’s Law: The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage rather than a constant amount.
• ​Plasticity: The brain's capacity for modification, as evident in brain reorganization following damage.

​Social & Cognitive Biases

• ​Availability Heuristic: Estimating the likelihood of events based on their availability in memory; if instances come readily to mind, we presume such events are common.
• ​Representative Heuristic: Judging the likelihood of things in terms of how well they seem to represent, or match, particular prototypes.
• ​False Consensus Effect: The tendency to overestimate the extent to which others share our beliefs and behaviors.
• ​Just-World Phenomenon: The tendency of people to believe the world is just and that people therefore get what they deserve and deserve what they get.
• ​Deindividuation: The loss of self-awareness and self-restraint occurring in group situations that foster arousal and anonymity.

Social Psychology & Group Dynamics

• ​Deindividuation: The loss of self-awareness and personal responsibility that occurs in group situations or anonymity.
• ​Reciprocity Norm: The social expectation that people will respond to each other in kind—returning benefits for benefits.
• ​Foot-in-the-Door Phenomenon: The tendency for people who have first agreed to a small request to comply later with a larger request.
• ​Door-in-the-Face Technique: A strategy for gaining a concession by first making a request so large that it is certain to be denied, then making a smaller, more reasonable request.
• ​Social Facilitation: The tendency for people to perform differently when in the presence of others than when alone (usually performing better on simple tasks).

​Memory & Learning Specifics

• ​Primacy Effect: The tendency to recall the first items in a list more easily than the middle items.
• ​Recency Effect: The tendency to recall the last items in a list more easily (because they are still in working memory).
• ​Anterograde Amnesia: The inability to form new memories after a brain injury or trauma.
• ​Retrograde Amnesia: The loss of memory-access to events that occurred or information that was learned before an injury or onset of a disease.
• ​Proactive Interference: When old information hinders the learning of new information.
• ​Retroactive Interference: When new information hinders the recall of older information.

​Developmental Stages & Concepts

• ​Zone of Proximal Development (ZPD): The gap between what a learner can do without help and what they can do with guidance (Vygotsky).
• ​Scaffolding: A teaching method that provides temporary support as students develop new skills.
• ​Schema: A mental structure that helps us organize and interpret information.
• ​Assimilation: The process of taking in new information and fitting it into existing schemas.
• ​Accommodation: The process of changing existing schemas to incorporate new information that doesn't fit.

​Perception & Biology

• ​Retinal Disparity: A binocular cue for perceiving depth; by comparing images from both retinas, the brain computes distance.
• ​Fovea: The central focal point in the retina, around which the eye's cones cluster (responsible for sharp vision).
• ​Myelin Sheath: A fatty tissue layer segmentally encasing the axons of some neurons; it speeds up the transmission of neural impulses.
• ​Absolute Refractory Period: The short time immediately after an action potential during which a neuron cannot fire again.

​Personality & Emotion

• ​Self-Actualization: The motive to realize one's full potential.
• ​Unconditional Positive Regard: A concept in humanistic psychology (Carl Rogers) of basic acceptance and support of a person regardless of what they say or do.
• ​James-Lange Theory: The theory that emotion results from physiological states triggered by stimuli (e.g., we feel sad because we cry).
• ​Cannon-Bard Theory: The theory that an emotion-arousing stimulus simultaneously triggers physiological responses and the subjective experience of emotion.

​Neuropsychology & Brain Anatomy

• ​Neurogenesis: The process by which new neurons are formed in the brain.
• ​Plasticity: The brain's ability to change its structure and function in response to experience or injury.
• ​Corpus Callosum: The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.
• ​Hippocampus: A neural center located in the limbic system that helps process explicit memories for storage.
• ​Prefrontal Cortex: The front part of the frontal lobe responsible for complex cognitive behavior, personality expression, and decision-making.
• ​Broca’s Area: An area in the left frontal lobe that directs the muscle movements involved in speech.
• ​Wernicke’s Area: A brain area involved in language comprehension and expression, usually in the left temporal lobe.

​Industrial-Organizational (I/O) Psychology

• ​Hawthorne Effect: The alteration of behavior by the subjects of a study due to their awareness of being observed.

Intelligence Quotient (IQ): A theoretical construct used to measure a person’s intellectual performance.

• ​Burnout: A state of emotional, physical, and mental exhaustion caused by excessive and prolonged stress.
• ​Transactional Leadership: A style of leadership that focuses on supervision, organization, and group performance through rewards and punishments.
• ​Transformational Leadership: A leadership style where leaders inspire and motivate followers to achieve extraordinary outcomes and develop their own leadership capacity.
• ​Job Satisfaction: A measure of workers' contentedness with their job, whether they like the job or individual aspects or facets of jobs.
• ​Organizational Culture: The shared values, beliefs, and behaviors that determine how a company's employees and management interact.