(a) In view of Piaget, "Intellectual development takes place through stages which occur in a fixed order and which are universal…

(a) Critical examination of Piaget's stage theory

Piaget held that cognitive development goes through four stages (sensorimotor, preoperational, concrete operational, formal operational) in a fixed order, driven by maturation and equilibration, in all cultures. Strengths: the broad sequence of achievements (object permanence, then conservation, then abstract reasoning) is found in many societies; the theory made children active constructors of knowledge and shaped education (discovery learning, readiness). Criticisms: Age and stage: infants show abilities earlier than he reported (Baillargeon's violation-of-expectation studies on object permanence), and conservation appears earlier when the task wording is simplified (McGarrigle and Donaldson, 1974), so competence was underestimated by his clinical method. Discontinuity: development is uneven rather than stage-like. Children vary across tasks (décalage), and training can speed up acquisition. Neo-Piagetians (Case, Fischer) and Siegler's overlapping-waves model describe gradual, domain-specific change. Culture: cross-cultural work (Dasen, 1972) found that conservation appeared later in some groups and that Aboriginal Australian children reached spatial concepts earlier than Western norms, showing ecological adaptation. Formal operations are not universal and depend on schooling and experience; Piaget himself conceded in 1972 that they may depend on aptitudes and occupation. Social context: Vygotsky argued that development is shaped by language, culture and guided interaction (zone of proximal development), which Piaget underplayed. Judgement: the sequence is a useful, largely robust description, but the claims of strict universality, sharp stages and independence from culture are too strong. Culture shapes the rate and the end point more than the order.

(b) Formation of stereotypes and prejudices

A stereotype is a generalised belief about the traits of members of a group (cognitive); prejudice is a prejudged attitude towards the group, usually negative (affective), which may lead to discrimination (behaviour). Allport (1954) described prejudice as antipathy based on a faulty, inflexible generalisation. Social categorisation: people sort others into in-groups and out-groups, and favour their own. Tajfel's minimal-group studies and social identity theory show that even trivial groupings produce bias. Example: regional and linguistic stereotypes in India. Social learning: children pick up attitudes from parents, peers, textbooks and media by imitation and reinforcement (Bandura). Example: caste or gender stereotypes learnt at home and in school. Realistic conflict: competition for scarce resources breeds hostility (Sherif's Robbers Cave study, 1954). Motivational and cognitive factors: scapegoating and frustration-aggression (Dollard et al., 1939), the authoritarian personality (Adorno, 1950) and illusory correlation, which links rare groups with rare negative acts (Hamilton and Gifford, 1976). Once formed, stereotypes persist through selective attention and confirmation bias. Contact under equal status and shared goals (Allport) reduces them.

(c) How a double-blind experiment controls experimenter bias and participant expectancy

Experimenter bias: an experimenter who knows the hypothesis may unwittingly treat the groups differently, or record ambiguous responses in the expected direction. In Rosenthal and Fode's (1963) study, students told that their rats were "maze-bright" got better results than those told the rats were "maze-dull", though the rats were the same. Participant expectancy: participants guess the aim and respond to demand characteristics (Orne, 1962) or improve through a placebo effect. In a double-blind design neither the participants nor the people who deliver the treatment and record the outcomes know who is in the experimental or control condition. A third party randomises and codes the conditions (identical drug and placebo pills, or coded materials), and the code is broken only after the data are analysed. Example: a trial of a new antidepressant versus an identical-looking placebo, rated by clinicians who do not know the allocation. This removes both sources of bias, so differences can be attributed to the independent variable. Limits: it is hard in psychotherapy, where the therapist knows the treatment, participants may guess from side effects, and blinding can be broken. In such cases blinded outcome assessors and active control conditions are used.