Emotion

A coordinated, context-sensitive pattern involving appraisal, subjective feeling, bodily changes and action tendencies. These components can dissociate; a facial expression is evidence about emotion rather than an infallible definition of it.

Guilt is an emotion involving remorse, self-reproach or a sense of responsibility for a perceived wrong or adverse outcome. The perceived responsibility can be accurate or mistaken; experiencing guilt is therefore different from establishing that a person actually caused a harmful event.^[ref]

For example, someone who damages another person's work might regret that action and want to repair the harm. Psychological descriptions commonly distinguish this action-focused appraisal from the broader negative self-appraisal associated with shame, although the experiences can overlap. A study can separately measure reported guilt, responsibility judgments and reparative behavior: one outcome should not be silently substituted for another.

The distinction matters when interpreting an experiment. A change in what participants say they feel does not automatically establish a change in what they do, and an observed apology does not uniquely identify the emotion that motivated it.

Difficulty identifying and describing one’s own emotions, often accompanied by an externally oriented thinking style. It is not synonymous with absence of emotion, autism or inability to care about others.

The proposal that some emotion-processing differences attributed to autism instead track co-occurring alexithymia. It predicts dimensional relationships across diagnostic groups, not that alexithymia explains every autistic experience.

A broad label for feeling-related states, often described along valence and arousal dimensions. Shared affect, emotion identification and compassionate concern are different experimental targets.

In the study of emotion, excitement commonly denotes an activated state of anticipation or engagement, often with positive emotional valence. It combines more than pleasantness alone: quiet contentment and eager anticipation can both feel good while differing in emotional arousal. A study must specify whether it measures a reported feeling, physiological activation or observable behavior; those measurements need not change in identical proportions. ^[ref]

Shame is a self-conscious emotion involving a negative evaluation of oneself in relation to an actual or imagined standard or audience. It is often distinguished from guilt focused on a particular action, although experiences can overlap. An experiment can separate evaluation of the self from evaluation of an act rather than treating every negative feeling after a mistake as the same process. ^[ref]

A change in one person's emotion attributable to information or influence from another person. It includes matching and complementary responses. Evidence must distinguish such influence from two people independently reacting to a shared event.

An interpersonal influence in which a recipient comes to experience affect resembling another person's affect. Facial mimicry, shared circumstances and social appraisal are possible contributors, but the presence of one does not establish the others.

The hypothesis that feedback arising from facial activity contributes to felt emotion. Weak versions predict modulation; stronger versions predict initiation, category-specific effects or necessity. These claims require different experimental tests.

Let $X$ be randomized assignment, $F$ facial activity, $M$ sensory feedback and $Y$ a report. One possible model is $F=X$, $M=F$, $Y=M$. A second is $F=X$, $M=F$, $D=X$, $Y=D$, where $D$ is an expectancy route. Both models predict the same observed $X,F,Y$ even though intervening on $M$ changes $Y$ only in the first. Therefore randomizing $X$ and measuring $F,Y$ does not distinguish these mechanisms. Identifying causal mediation requires further assumptions or interventions. The binary models are a logical counterexample, not participant data.

The 1988 experiment associated with Fritz Strack used different ways of holding a pen to facilitate or inhibit facial activity associated with smiling. The manipulation was intended to avoid explicitly asking participants to act happy. Its interpretive importance lies in separating bodily feedback from explicit labeling; its limitation is that different postures can also change effort and task experience.^[ref]

Information about facial activity available to the organism, including bodily sensory consequences and information used in interpreting its own state. A manipulation of facial movement can change several other things as well; its total effect on a report does not uniquely identify this route.

A family of accounts in which evaluation of events in relation to goals, well-being and coping possibilities shapes emotion. Cognitive appraisal can be fast and nonverbal. A theory requiring appraisal for every emotional episode must specify the appraisal process independently enough to permit a counterexample.

The account that another person's reaction changes an observer's evaluation of an event, and thereby the observer's emotion. The process can be rapid and need not involve consciously naming the other's feeling. It permits complementary outcomes, such as another person's anger contributing to the observer's fear.

Using another person's emotional reaction as information about an event or relationship. Establishing this mechanism requires evidence about the recipient's evaluation, beyond a correlation between the two people's reports.

Surprise is an emotion associated with an unexpected event or a discrepancy from an expectation. It does not determine pleasantness: an unexpected welcome visitor and an unexpected loss can both be surprising while having different emotional valence. Research can manipulate event probability or prior information and then measure reported surprise, orienting or changes in prediction. These are related operational measures rather than one interchangeable signal. ^[ref]

Sadness is an unpleasant emotion commonly associated with loss, disappointment or reduced access to a valued goal. Studies distinguish the immediate feeling from its intensity, duration and accompanying behavior. For example, a brief response to a sad story is different from persistent depressed mood accompanied by functional impairment. The emotion name alone does not establish a clinical diagnosis of depression. ^[ref]

Happiness can name a pleasant emotional state or a broader evaluation of how life is going; psychological measurement needs to distinguish these meanings. A report of current affect samples a moment, while a life-satisfaction judgment summarizes a different time frame. Repeated experience sampling can reveal variation within a person that a single global rating misses. Neither measure alone specifies one universal physiological pattern. ^[ref]

Anger is an emotion often associated with perceived obstruction, unfairness or a harmful action attributed to another agent. Feeling anger, displaying it and acting aggressively are different events. In negotiation experiments, information that a partner was angry could affect concessions, illustrating an interpersonal consequence of a communicated emotion without making anger identical to aggression. ^[ref]

An aspect of an emotional episode, such as cognitive appraisal, felt experience, bodily regulation, facial movement or readiness to act. Components can vary partly independently. A theory must state which components its evidence actually measures.

A family of theories proposing a limited set of biologically grounded basic emotions. Versions differ in how strongly they predict distinctive facial, physiological and behavioral patterns. A claim of fixed one-to-one patterns is stronger than a claim of inherited response biases that interact with context.

An emotion proposed as a biologically primary category in a basic emotion theory. The status of a category is a theoretical and empirical claim, not something established merely by giving observers a category word in a forced-choice emotion recognition task.

An aversive subjective experience that can accompany anxiety, intrusive memories or other difficulties. Its intensity is distinct from the conviction of a belief, a physiological response or functional impairment.

The degree of activation associated with an emotional state. Emotional arousal is distinct from emotional valence: both positive and negative states can be highly activating.

The positive or negative evaluative quality of an experience or stimulus. Agreement about emotional valence is weaker than agreement about a particular discrete emotion category.

A configuration or movement of the face that can contribute to communication and sensory regulation. Similar production across populations does not imply identical emotion recognition, and an expression can be posed or socially regulated.

Facial reactions congruent with another person's observed facial movements. Facial electromyography can measure small congruent responses. Congruent movement alone does not establish emotional contagion or a necessary route to emotion recognition.

A system for describing visible facial actions in terms of anatomically grounded action units. Coding an action unit documents a movement; assigning an emotion to the movement is a separate inference.

Movement of facial muscle groups, described without assuming its psychological cause. Calling a movement an expression of an emotion adds an interpretation that requires independent evidence.

Description of visible facial movements in terms of anatomically informed action components. Coding the movement keeps an observation separate from an inferred emotion label; a code by itself does not prove the observer's emotional interpretation.

A socially learned convention regulating when and how a facial expression is shown. Display rules can alter a visible signal without implying that every underlying feeling or production mechanism is culture-specific.

An emotion associated with rejection or aversion. A facial configuration labeled disgust can have sensory consequences without uniquely identifying the feeling of its producer.

An emotional response to perceived threat. The experience of fear, defensive behavior and a facial expression interpreted as fear should be distinguished when measuring it.