taboo: something that is avoided, banned, or not allowed because of a cultural belief.

tabula rasa: (translation: 'blank slate'), refers to the behaviourist belief that all human behaviour is infinitely plastic and malleable, and therefore can be explained in terms of learnt experiences, rather than genetic predispositions.

tardive dyskinesia: a condition that is occasionally experienced as a side-effect of antipsychotic drugs, typified by involuntary movements of the tongue, lips, jaw and other facial movements.

taste aversion: refers to a type of learning formed after one trial, whereby an association is formed between feelings of sickness and (usually) a particular food, resulting in an avoidance of the food.

telegraphic speech: refers to the reduced sentences (resembling telegrams) that distinguish children's speech patterns from around 18 months to two years, demonstrating the basics of early grammar by containing crucial nouns and verbs.

telic state: a motivational state in which arousal is avoided.

temperament: aspects of personality that exist at birth and are believed to be as a result of genetic influences.

template theories: an account of pattern recognition; the proposal that we match incoming information with templates (miniature representations) of patterns stored in long-term memory.

temporal lobe: the region of the cortex below the lateral fissure; contains the auditory cortex.

territoriality: the tendency of animals to defend (e.g. through scent markings) a particular geographical area from other members of their own species, in order to gain access to and increase control over a resource.

testosterone: a male sex hormone produced by the testes, that is responsible for production of sperm and  the development of the secondary sexual characteristics. It has also been associated with aggression.

test-retest reliability: measure of measurements consistency, by correlating (the same) test performance on two different occasions.

thalamus: part of the forebrain, transmits nerve impulses, up sensory pathways to the cerebral cortex. Damage to the thalamus can result in anterograde amnesia.

thanatos: a Freudian term which represents the death instinct, characterised by aggressive behaviour and a rejection of pleasurable stimuli.

thematic apperception test (TAT): a projective test, whereby individuals are presented with ambiguous pictures and asked to generate a story from them, thereby reveal personality characteristics, motivation for power, achievement and affiliation, and in a clinical setting, any underlying emotional problems.

theory: a structured set of concepts to explain a phenomena or group of phenomena.

theory of mind: child's understanding of the emotions and motives of other people.

therapeutic: having a beneficial effect on mental health.

therapy: any process that aids understanding and recovery from psychologicaldifficulties. A wide variety of therapies can be divided into psychotherapies(involving discussion or action) and somatic therapies (medical or biological intervention).

think-aloud protocol: comments made when by experimental participants of the mental processes and approaches used whilst working on a task.

third force: term used to describe the development of the humanistic perspectiveas an alternative to the psychoanalytic and behaviourist perspectives.

Thorndike puzzle-box: piece of laboratory apparatus used by Skinner, to demonstrate trial-and-error learning.

thought: an idea; an instance of thinking; the state or condition of thinking.

thought disturbances: in abnormal psychology, distortions of thought processes such as incoherent speech.

thought disorder: in abnormal psychology, a general term to describe disturbance of thought or speech that might be symptomatic of a mental disorder, for instance incoherent thought and speech patterns.

Thorndike (1874-1949): renowned for his animal research, exploring trial and error learning (known as instrumental learning) in animals through the development of the Thorndike 'puzzle-box'

three mountains test: a Piagetian task to demonstrate egocentricity, whereby children are shown a model of three mountains, and watches as a doll is positioned at a different point around the mountains. Pre-operational egocentric children are unable to see from the dolls perspective of the mountains.

tip of the tongue phenomenon: a term used to refer to the experience when we feel that we know a particular word, yet are unable to retrieve it.

token economy: using the principles of operant conditioning, a behaviour modification technique used to encourage particular behaviour, through the employment of secondary reinforcers (tokens) after desirable behaviour, which can be collected and exchanged for primary reinforcers (a meaningful object or privilege).

tolerance: over time, the need for greater dosages of a drug in order to achieve the same effect.

Tolman (1886 ?1959): an American psychologist who concentrated on learning (escape, latent, avoidance, approach and choice-point learning) in rats, most commonly in mazes.

top-down approach: in the context of offender profiling, an approach that examines evidence from the crime scene in light of existing classifications and theories of serious crimes (the 'top') and appraises which category a particular crime fits into. Commonly used by American criminal profilers.

top-down processing: perceptual processing in which previous experiences, existing knowledge, expectations, motivations or the context in which perceptiontakes place, affect how a perceived object is interpreted and classified.

Tourette's syndrome: neurological disorder characterised by facial grimaces and tics and movements of the upper body and grunts and shouts and coprolalia.

trace-dependent forgetting: the information no longer stored in memory.

trait: a specific personal characteristic or attribute which occurs consistently and influences behaviour across a range of situations.

transference: a process during psychoanalysis, whereby a client attaches feelings towards the therapist that were previously unconsciously directed towards a significant person in their life, who may have been involved in some form of emotional conflict.

transfer of training: refers to the way in which skills learnt in one situation may to be transferred to a second, related situation.

trauma: term used either for a physical injury (as a result of an external force), or a psychological injury (caused by an emotional event).

Treisman (1935-): A British psychologist specialising in visual attention and object perception, renowned for proposing the feature integration theory of attention.

trial: in experimental psychology, a single unit of experimentation where a stimulusis presented, an organism responds and a consequence follows.

trial-and-error learning: originally proposed by Thorndike, a view of learning that proposes responses that do not achieve the desired effect are gradually reduced, and those that do are gradually strengthened.

turing test: a test to determine how closely computers mimic human cognitive process.

two factor theory of emotion: is a social psychology theory that views emotion as having two components (factors): physiological arousal and cognition. According to the theory, "cognitions are used to interpret the meaning of physiological reactions to outside events."

twin studies: refers to studies where monozygotic and dizygotic twins are studied to assess the relative contributions of genetic and environmental influences on a particular characteristic, e.g. intelligence.

type 1 error: rejecting the null hypothesis when it should be accepted.  Also called a false positive.

type 2 error: accepting the null hypothesis when it should be rejected.  Also called a false negative.

type A personality: a set of personality characteristics, including a sense of competitiveness, hostility, a constant sense of time pressure and impatience, which result in an increased risk of coronary heart disease.