Society, Human Behaviour and Communities II: Normal and Abnormal Behaviour, the Life-Span Perspective with Developmental Tasks and Hazards, Psychoanalytic, Behavioural and Humanistic Theories of Personality, and Social Psychology from Perception and Attitudes to Collective Behaviour

The life-span perspective, associated with Paul Baltes, holds that development is lifelong, multidimensional, multidirectional (gains and losses at every age), plastic and embedded in history and context. Elizabeth Hurlock's Developmental Psychology: A Life-Span Approach divides life into periods and, for each, describes its characteristics, developmental tasks and hazards, physical and psychological. The concept of developmental tasks is Robert Havighurst's (Developmental Tasks and Education, 1948): tasks that arise at a certain period, successful achievement of which leads to happiness and success with later tasks, while failure leads to unhappiness, social disapproval and difficulty later. They arise from physical maturation, cultural pressure and the individual's own values and aspirations.

Sigmund Freud's psychoanalytic theory describes a personality structure of id (the instinctual, pleasure-seeking part), ego (the realistic mediator, working on the reality principle) and superego (the internalised moral standards). Personality develops through psychosexual stages, oral, anal, phallic, latency and genital, and fixation at a stage leaves characteristic traits. The ego protects itself from anxiety by defence mechanisms: repression (pushing threatening material out of awareness), denial, projection (attributing one's own unacceptable impulses to others), displacement (redirecting feelings to a safer target), rationalisation, reaction formation (expressing the opposite of what is felt), regression and sublimation (channelling impulses into acceptable activity). Neo-Freudians revised the theory: Carl Jung proposed the collective unconscious and archetypes, and the attitudes of introversion and extraversion; Alfred Adler the inferiority complex, striving for superiority and the style of life; Erik Erikson eight psychosocial stages across the whole life.

Behavioural theories explain personality as learned behaviour. Ivan Pavlov showed classical conditioning, in which a neutral stimulus comes to evoke a response after pairing with one that naturally evokes it; John B. Watson founded behaviourism; B. F. Skinner showed operant conditioning, in which behaviour is shaped by its consequences, strengthened by reinforcement and weakened by punishment or extinction. Albert Bandura's social learning theory added observational learning, demonstrated in the Bobo doll experiments (1961), self-efficacy (1977) and reciprocal determinism among person, behaviour and environment. Humanistic theories stress growth and choice. Abraham Maslow's hierarchy of needs (1943) runs from physiological needs through safety, love and belonging and esteem to self-actualisation. Carl Rogers held that people have an actualising tendency, that distress arises from incongruence between the self-concept and experience, often created by conditions of worth, and that growth follows when a helper offers three core conditions: empathy, unconditional positive regard and congruence or genuineness.

Social perception is how people form impressions of others and explain their behaviour. Solomon Asch (1946) showed that central traits such as "warm" or "cold" shape the whole impression. Attribution theory, begun by Fritz Heider (1958), asks whether behaviour is attributed to internal, dispositional causes or external, situational ones; Harold Kelley's covariation model uses consensus, distinctiveness and consistency. The fundamental attribution error, named by Lee Ross (1977), is the tendency to overestimate dispositional and underestimate situational causes when explaining others' behaviour. For a social worker this is a professional hazard: attributing a family's poverty to laziness rather than to unemployment or debt is the fundamental attribution error at work, and it is also what the public often does to clients.

An attitude is a relatively enduring evaluation of an object with cognitive, affective and behavioural components. Attitudes are formed through direct experience, conditioning, observation and socialisation. Theories of attitude change include Leon Festinger's cognitive dissonance theory (1957), which holds that inconsistency between beliefs and behaviour creates discomfort that people reduce by changing one of them; Heider's balance theory; the Yale approach of Carl Hovland, which studied who says what to whom (source credibility, message and audience); and the elaboration likelihood model of Richard Petty and John Cacioppo (1986), with its central and peripheral routes to persuasion. Attitudes are measured by the Bogardus social distance scale (1925), the Thurstone scale of equal-appearing intervals (1928), the Likert summated rating scale (1932), Guttman's cumulative scale and Osgood's semantic differential (1957). Communication in social psychology concerns the transmission of meaning through verbal and non-verbal channels, the effects of source, message and channel, and barriers such as noise, perception and status differences, all of which bear on interviewing.

Collective behaviour is relatively spontaneous and unstructured behaviour of large numbers of people: crowds, mobs, panics, rumours, fads and the early stages of social movements. Gustave Le Bon's contagion theory (The Crowd, 1895) held that in a crowd individuals lose their rational selves and are swept by a "collective mind" through anonymity, contagion and suggestibility. Convergence theory, associated with Floyd Allport, reverses the direction: crowds form when people who already share dispositions come together, so the crowd expresses rather than creates their behaviour. Ralph Turner and Lewis Killian's emergent norm theory (1957) holds that crowds are not uniform; in an ambiguous situation new norms emerge through interaction, often led by a few, and define what is appropriate. Neil Smelser's value-added theory (Theory of Collective Behavior, 1962) lists six determinants, each necessary and adding value to the previous: structural conduciveness, structural strain, the growth and spread of a generalised belief, precipitating factors, mobilisation of participants for action, and the operation of social control.