ablation: surgical removal of brain tissue, used to aid identification of brainlocalisation.

abnormal behaviour: behaviour which is regarded by society as deviant or maladaptive; according to DSM, an individual must be suffering or show maladaptive functioning in order for behaviour to be described as abnormal.

abnormal psychology: the empirical study of abnormal behaviour, which seeks to describe, explain and predict abnormal behaviour.

absent-mindedness: may refer to 1) a low level of attention ("blanking" or “zoning out”); or 2) intense attention to a single object of focus (hyperfocus) that makes a person oblivious to events around him/her; or 3) unwarranted distraction of attention from the object of focus by irrelevant thoughts or environmental events.

absolute threshold: the minimum amount of energy required for a sensory experience to be produced

abstinence syndrome: see withdrawal.

abstract: existing only in the mind; separated from embodiment; "abstract words like `truth' and `justice'".

accessibility: in long-term memory, the principle that remembering and forgetting are dependent on effective retrieval; without the proper cues, information which exists in long-term memory may not be accessible.

accommodation:  in Piaget's theory of cognitive development, the process of changing existing schemas when new information cannot be assimilated.

acetylcholine: is a neurotransmitterfound in the brain, where it is crucial for the regulation of memory (loss of acetylcholine has been implicated in Alzheimer’s disease) and in the peripheral nervous system, where it activates the actions of muscles.

achievement motivation: is the inclination to persevere at tasks that may be complex or demanding for the individual.

acquired immune deficiency syndrome (AIDS): is a deadly disease caused by the 'human immunodeficiency virus -HIV', that weakens the immune system and subsequently, the body’s resilience to fight infection.   

action potential: the nerve impulse that travels down the axon and triggers the release of neurotransmittersinto a synapse.

action slips: a form of absent-mindedness where a person performs an action that was not intended; caused by not paying attention to what is going on.

activity theory: proposes that individuals prefer to remain active and productive in later life, even resisting disengagement from society - contrasts with social disengagement theory.

actor/observer biases: these refer to the tendency for (a) ‘actors’ to explain their own behaviour in situational terms and (b) observers to explain the behaviour of others in dispositional (person) terms.

actualisation: an important concept in humanistic psychology, meaning the achievement of one's potential.

actualizing tendency: in Rogers's theory, an innate drive which reflects the desire to grow, to develop and to enhance one's capacities.

adaptation: a feature of an organism that has been shaped by natural selection so that it enhances the fitness of its possessor. Alternative meaning: One adapts the way of living to the medicine and will then be forced to change one's living habits if one has to stop taking the medicine. An example of this is if one lives a verystressful life and manages to continue with this due to sedatives.

addiction: now little used term that referred to physical dependence and was associated with its negative effects, such as on social functioning.

Adler (1870-1937)- an Austrian doctor and psychologist, who was initially influenced by Freud, and later developed his own theory of personality andpsychotherapy, through “individual psychology”. Adler strongly believed in treating each patient holistically as a “whole person”, and a range of his ideas and techniques have been applied to a variety of psychology, including cognitive behavioural therapy and holistic psychology.

adoption studies: employed to demonstrate the influence of genetics (as opposed to environment) by comparing the correlations between adopted children and either their biological parents or adoptive parents on a measurable trait (e.g. intelligence).

Adorno (1903-1969): was a philosopher, sociologist and composer.  Within social psychology, is largely remembered for defining the authoritarian personality (characterised by intolerance of ambiguity, prejudiced attitudes and conformity to authority, with an emphasis on the influence of childhood experiences and internalisation) and the subsequent development of the F-scale (a measurement of the authoritarian personality).

adrenal glands: endocrine glands, located just above the kidneys, which play an important role in arousal and stress; the outer layer, the cortex, secretescorticosteroids and the medulla (the inner core) secretes epinephrine(adrenaline) and norepinephrine(noradrenaline).

adrenocorticotropic hormone (ACTH): released by the anterior pituitary during stressful situations. ACTH, in turn, triggers the release of corticosteroids (another type of hormone). Corticosteroids produce many of the effects of the stressresponse.

advertising: seeks to influence consumer attitudes and behaviour, through a variety of persuasive techniques, for instance use of fear appeals.

aetiology:  the study of the causes of a disease or mental disorder.

affect: emotion or mood, e.g. sadness. Within abnormal psychology, patients may display different types of affect disturbance, e.g. blunted, flat or inappropriate affect.

affectionless psychopathy: condition proposed by Bowlby, whereby individuals display little remorse or guilt for their crimes.

affective disorder: see mood disorder.

afferent neurons: the communication of the senses experienced by the body are conveyed to the central nervous system by afferent neurons for processing.

affiliation: the desire of people to associate with others.

ageism: a form of stereotyping and discrimination against the elderly.

agency: the belief that human beings are free to make decisions and have control over their own lives.

agency theory: theory developed by Milgram to explain why people obey orders that go against the conscience. When people see themselves as mere agents of another person, they will obey that person's orders, feeling themselves free of individual responsibility.

aggression: an action or a series of actions where the aim is to cause harm to another person or object.

agoraphobia: anxiety disorder in which a person feels anxiety about experiencing panic attacks in public, and therefore avoids public situations.

AIDS: see acquired immune deficiency syndrome.

aims: the general investigative purpose of the study.

alarm reaction: see general adaptation syndrome.

alcoholism: physical dependency on alcohol.

alpha/beta bias: alpha bias refers to theories and research which assume real and enduring differences between men and women. Beta bias theories and research have traditionally ignored or minimised differences between men and women.

alpha rhythm/waves: the average brain wave pattern (between eight to thirteen per second) whilst in a relaxed, wakeful state.

altered states of awareness: any state of awareness which differs from normal waking awareness; examples include meditation, sleep, drug states and psychosis.

alternative hypothesis: a testable statement that states the expected result of the study, specifying the effect of the independent variable upon the dependent variable, based on the researcher's knowledge from observations, related studies and previous investigations.

altruism (animal): an animal is considered to be engaging in altruistic behaviour when by so doing it increases the survival chances of another animal whilst decreasing its own.

altruism (human): as with animal altruism, this involves some cost to the altruist and some benefit to the recipient. Unlike animal altruism, there is often evidence of 'kindly intent' on the part of the altruist.

Alzheimer's disease: A degenerative brain disorder, which is characterised by gradual memory loss, deteriorating cognitive skills, increasing disorientation and a reduction in intellectual ability. Linked to the deterioration of acetylcholine pathways in the brain.

ambiguous figure: any stimulus which can be perceived in more than one way. 

American Sign Language: manual-visual language system, including gestures, used by hearing-impaired individuals in America.

amnesia: a significant loss of memory as a result of brain damage or psychologicaltrauma. Anterograde amnesia refers to the inability to learn and remember new information after brain damage and retrograde amnesiarefers to the loss of memories from before brain damage.

amphetamine delusional disorder: a form of mental disorder resulting from the excessive use of amphetamines; its primary symptom, extreme paranoiddelusions, can make it appear symptomatically identical to paranoid schizophrenia.

amygdala: an almond-shaped structure in the limbic system which plays a role in basic emotions, aggression and the development of emotional memories.

anal personality: an adult who has remained ‘fixated’ during the anal stageof psychosexual development and displays an anally retentive personality, which is characterised by obsessive cleanliness, stinginess and aggressiveness, as a result of either excessive or insufficient gratification of id impulses during the anal stage.

anally retentive: commonly abbreviated to "anal", is used conversationally to describe a person with such attention to detail that the obsession becomes an annoyance to others, and can be carried out to the detriment of the anal-retentive person.

anal stage: the second stage in Freud's theory of psychosexual development, from 15 months to 3 years. According to psychoanalytic theory - when the child's main source of pleasure is the anus.

analytical psychology: branch of psychology developed by Jung - emphasizes the interplay between oppositional forces within the psyche and the ways in which these internal conflicts affect personality development.

analysis of variance (ANOVA): see covariation principle.

androcentrism: refers to the tendency of some theories to offer an interpretation of women based on an understanding of the lives of men (see also alpha/beta bias).

androgens: hormones whose functions are related to masculine characteristics; the most important is testosterone.

androgyny: gender role identity where an individual possesses both male and female (personality) characteristics.

anger management: a programme designed to teach individuals how to apply self-control in order to reduce anger against others.

animal language: as an area of research, this refers to either (a) attempts to teach nonhuman animals to speak, or (b) studies of animals' 'natural' language in their own natural environment.

animal research: the use of non-human animals in empirical research, on the basis of greater control, objectivity and similar genetic makeup. However, the use of non-human animals has raised a number of ethical and moral questions.

animism: the belief that inanimate objects are alive and as such have life-like qualities such as feelings and intentions. A child may get angry and smack his bicycle because it 'made him get hurt'. Animism is a characteristic found in children in Piaget's second stage of intellectual development, the pre-operational stage. Piaget believed that animism was a characteristic of the child's egocentricreasoning - if the child has feelings and intentions, then so must all other things.

anonymity: a state for an individual within a crowd where each person loses their sense of individuality.

anorexia nervosa: (literally, a nervous loss of appetite) a disorder characterised by the pursuit of extreme thinness and by an extreme loss of weight.

ANS: see autonomic nervous system.

antagonist: a substance that hinders the activity of a neurotransmitter, through reducing the amount available.

antagonistic: opposition in physiological action; especially : interaction of two or more substances such that the action of any one of them on living cells or tissues is lessened.

antecedent control: a behavioural measure in which the intervention occurs before the behaviour arises. Antecedent procedures include education, attitude change and inducing or preventing behaviours by controlling the triggers which cause them to occur.

anterior pituitary: The front portion of the pituitary, a small gland in the head called the master gland. Hormones secreted by the anterior pituitary influence growth, sexual development, skin pigmentation, thyroid function, and adrenocortical function.

anterograde amnesia: the inability to learn and remember new information after brain damage.

anthropomorphism: assigning human feelings and emotions to non-human animals.

anti-anxiety drug: a drug which functions as a central nervous systemdepressant, but whose primary behavioural effect is the reduction of anxiety.

anti-conformity: refers to behaviour carried out in order to oppose the norms of the group.

anti-depressants: a drug which is used to treat clinical depression, primarily by enhancing the activity of the neurotransmitter serotonin.

anti-inflammatory: a medication to reduce inflammation (the body's response to surgery, injury, irritation, or infection).

anti-social behaviour: this is a general term used to refer to any behaviour that harms or offends another person. Common examples are aggressionand discrimination.

anti-social personality disorder: individuals who show a lack of regard for others, are impulsive, and behave in an socially unacceptable manner.

anti­psychotic drug: a drug used to treat psychotic symptoms, such as disordered thoughts, delusions, or hallucinations.

anxiety: a negative emotional state, characterised by high physiological arousaland nervousness or fear.

anxiety disorders: the most common of adult mental disorders, characterised by severe anxiety and feelings of tension. Phobias are probably the most familiar of these disorders.

APA: the American Psychological Association

aphasia: language impairment as a result of brain injury or lesions.

aphonia: an inability to produce normal speech sounds.

applications: actual or possible ways of using psychological knowledge in an applied or practical setting.

appraisal: a judgement about whether a potentially stressful situation is threatening, challenging or harmful.

archetypes: in Jung's theory, patterns or frameworks within the collective unconscious which serve to organise our experiences, providing the basis of many fantasies, myths and symbols.

arousal: refers to the body's level of alertness and activation as reflected in certain physiological responses such as heart rate or muscle tension.

artificial intelligence (AI): in computer science, the attempt to build machines which can function intelligently, and the use of such machines to test our understanding of human intelligence.

Asch effect: see conformity (majority influence)

assimilation: in Piaget's theory of cognitive development, the process of fitting new information into existing schemas.

association areas: parts of the cortex that receive input from more than one sensory system.

assumption: something taken for granted as being true.

Atkinson and Shiffrin (1968): proposed the multi-store model of memory, comprised of three stages; incoming sensory information, short-term memory (7+/- 2 “chunks” of information) and long-term memory.

Atkinson and Shiffrin model of memory: also known as the multi-store model of memory. Proposes the existence of three separate but linked systems – sensory memory, short-term memory and long-term memory.          

attachment: a two-way bond between two individuals (humans or some other animal species), in which each individual gains a sense of security from the other.

attachment theory: a psychodynamic approach to developmental psychology, which places a lot of emphasis on the formation of a secure attachment between infant and primary carer(s).

attention: the process of selectively focusing on particular stimulus elements, typically those deemed most significant.

attention deficit disorder (ADD): neurological condition that is often evident from childhood. ADD may cause restlessness, disorganisation, hyperactivity, distractibility, and mood swings.

attenuator model of attention: Treisman's proposal that, instead of selecting one channel and blocking the others, the filtering mechanism (a) selects one channel and passes it on for semantic analysis, and (b) allows the unattended channels through for processing but in weakened (attenuated) form.

attitude: a personal belief of an evaluative nature, such as good or bad, likeable or not likeable, which influences our reactions towards people or things.

attribution (of causality): the way in which we infer the causes of our own or another person's behaviour according to a set of cognitive rules and biases. As a result of these strategies we decide whether a person's behaviour is caused by their own stable characteristics, or whether it is a result of situational influences.

attribution theory: a theory that seeks to explain the causes of behaviour in terms of either dispositional (personality) factors or situational factors.

attributional biases: in attribution theory, common faults in attributing causes to behaviour such that mistakes are made and the causes of behaviour are misunderstood. An example is self-serving bias in which we attribute our own good and worthy behaviours to personality factors (I gave my mum a bunch of flowers because I am kind) and any bad or unworthy behaviours to situational factors (I shouted at mum because I've got a headache).

audience effect: how performance on a task can be affected by others watching – either improves performance (social facilitation) or reduces performance (social inhibition)

auditory adaptation: the tendency of repeated or continuous sounds to appear less loud over time. As we habituate to the stimulus of the sound its apparent loudness decreases.

auditory cortex: the area of the brain (in the temporal cortex) that connects fibers of the auditory nerve and interprets nerve impulses in a form that is perceived as sound.

auditory fatigue: occurs on exposure to intense sounds which cause a persistent reduction in apparent loudness.

autonomic conditioning (also called 'learned operant control of autonomic responses'): the conditioning of changes in autonomic (involuntary) responses (such as heart rate or blood pressure) by means of operant reinforcement.

authoritarian personality: personality style strongly associated with prejudicedattitudes, where the person is intolerant of ambiguity or uncertainty, submissive to those in authority and dismissive or arrogant towards those perceived to be of lower social status.

autistic disorder (autism): a developmental disorder, whereby children are unresponsive and avoid contact with others, and demonstrate a lack of language and communication skills. Autism is a type of pervasive developmental disorder.

autokinetic effect: an optical illusion experienced when a person in a totally dark room sees a stationary spot of light appearing to move.

automatic processing: a rapid mental operation that does not involve conscious awareness and often improves with practice, e.g. the Stroop effect.

autonomic nervous system: part of the nervous system that maintains the normal functioning of the body's inner environment The ANS has two subdivisions: (a) the sympathetic division whose activity mobilises energy resources and prepares the body for action, and (b) the parasympathetic divisionwhose activity tends to conserve the body's energy resources and restore inner calm.

availability: in memory, the principle that remembering is determined by whether the information exists in long-term memory or not; forgetting implies that the information is destroyed.

availability heuristic: a rule of thumb used to make decisions about frequencies of events based on how easily relevant examples can be remembered  a cognitiveshort cut

aversion therapy: a behavioural treatment that aims to rid the individual of an undesirable habit (e.g. smoking) by pairing the habit with unpleasant (aversive) consequences.

aversive: an unpleasant stimulus or event.

aversive conditioning: a form of behaviour modification which is designed to induce an aversive response to stimuli which are associated with existing undesirable behaviours.

awareness: in biological psychology, awareness comprises a human's or an animal's perception and cognitive reaction to a condition or event. Awareness does not necessarily imply understanding, just an ability to be conscious of, feel or perceive.

axon: the relatively elongated portion of a neuron between the cell body and the terminals which provides the signal pathway for a nerve impulse.