Glossary
laissez-faire leaders: leaders who are not interested in the views and opinions of other group members
language acquisition device (LAD): the supposition that children acquire language by matching the speech they hear to appropriate elements of universal grammar
language: there is no one definition of this term. A form of communication where the organisation of the elements can result in different meanings, and where there is structural dependency between these elements
late selection models: models in selective auditory attention which posit the existence of a selective mechanism late in auditory processing
latent conditions: in the study of human error, systemic conditions in which errors are likely to occur
latent learning: a form of learning that is not immediately expressed in an overt response
lateral geniculate nucleus (LGN): part of the thalamus which processes visual information received from the retina
lateral hypothalamus (LH): part of the hypothalamus
lateral inhibition: a type of cell-to-cell interaction whereby one cell inhibits its immediate neighbours from activating
Latin square counterbalancing: a form of experimental design aimed at eliminating order and practice effects by adjusting the order in which different groups of participants undergo different treatments. If there are three experimental conditions, A, B and C, you would require three groups who did the tasks in the following orders: ABC, CAB, BCA. Note that each task appears once in each temporal location across the groups
law of pragnanz: the Gestalt idea that there is a strong tendency in perception to see the best figure leadership: a role defined by the group for getting other group members to realise the groups’ goals
learned helplessness theory: a theory of depression first proposed by Seligman (1976), in which depression may be caused by the individual experiencing unavoidable and uncontrollable negative life events
learning model: the theoretical approach to psychopathology and treatment that is based on behaviourist principles and learning theory (e.g. operant and classical conditioning)
lemma: an early, abstract form of a word which will later be output
leptin: a peptide hormone that is produced by fat cells and plays a role in body weight regulation by acting on the hypothalamus to suppress appetite and burn fat stored in adipose tissue
leptokurtic: a distribution of scores that has relatively few scores at the extremes. These distributions tend to look pointy (see Figure 38.4)
levels of explanation: a given psychological phenomenon can be explained at a number of levels, corresponding to the units used in explanations. Examples include the social psychological level, where explanations are in terms of inter-personal behaviour, and the physiological level, where explanations are in terms of brain operation or genetics
levels of measurement: the relationship between what is being measured and the numbers obtained on a scale
levels of processing: the idea that memory for information is an incidental consequence of the depth to which the information has been processed
levels: the categories of a categorical variable are often referred to as levels (especially when these categories are determined as part of an experimental manipulation). For example, an experiment that compares a drug intervention with a placebo is said to have one variable (type of drug) with two levels. If we added a condition in which an alternative drug was used, there would still be one variable (type of drug) but it would now have three levels: placebo, drug A and drug B
lexical decision task: a task which presents participants with a letter string which may or may not be a word and which requires him/her to decide as quickly as possible which it is
lexical selection: the first stage of lexicalisation, in which words that fit the desired meaning are selected from the mental lexicon
lexicalisation: the process by which a word meaning is turned into a blueprint for the sound
lexicon: the representations which underpin our knowledge and use of words
libido: in Freudian theory, the instinctual or energy force that drives the id
lie detection: the practice of determining whether someone is lying
life events: external events or experiences which will represent either challenges (e.g. a new job), losses (e.g. death of a close relative) or threats (e.g. the threat of redundancy)
ligands: a molecule that binds to a receptor
likert scale: a technique for measuring attitudes. People rate their agreement or disagreement with a number of statements about a particular attitude object liking: to feel attraction toward another person or object and take pleasure in their company
limbic system: a system within the brain that consists of the hippocampus, amygdala, cingulate cortex, fornix, septum and mamillary bodies
line chart: a graph displaying some statistical property (e.g. the mean) of an outcome variable, for unordered categories of data. The statistical property is displayed as a symbol, and related values are connected with a line (see Figure 38.9)
line of best fit: when scores have been collected on two variables, the straight line that when fitted to these scores produces the least error. It’s worth noting that even though it is the line of best fit, it doesn’t necessarily mean that it is a good fit, just that it’s better than any other straight line that could have been fitted
linear perspective: the way in which parallel lines appear to converge as they recede from the observer is a cue to depth and distance from the observer
linguistic intelligence: the ability to use words and language
locus of control: the extent to which people believe that events can be controlled by them (an internal locus of control) or that those events happen to them because they are controlled by external factors (an external locus of control)
logical concepts: logical concepts are governed by and identified by clear and unambiguous rules. Examples and non-examples of the concept are distinguished by rule
logical definitions: definitions of what people understand by the word intelligence obtained through reasoning and observation
logical-mathematical: the ability to use reason, logic and numbers
logogen model: a model of word recognition in which word meaning is represented by a logogen and which collects evidence from both the input and the context until the logogen’s threshold of activation is exceeded and it fires
logogen threshold: the amount of evidence required before a logogen fires
long-term memory: a general reference to memories that are retained for a long time. Technically, memories that survive for more than about half a minute in the absence of rehearsal
long-term potentiation (LTP): the long-lasting enhancement in communication between two neurons that results from stimulating them simultaneously. Considered to be the neural basis of memory
longitudinal: a study that follows of participants over a period of time, usually over one or more years
loss aversion: when a loss counts more than it should logically, resulting in an inclination to make a judgement which entails loss loving: the emotions, cognitions and behaviours that are involved in an intimate relationship
loving the emotions, cognitions and behaviours that are involved in an intimate relationship
lower quartile: the value in a set of ordered observations that splits the lowest 25% of scores