(a) What do you mean by defense mechanism? Distinguish between healthy and unhealthy defense mechanisms. Explain how it…

(a) Defence mechanisms: healthy versus unhealthy, and personality

Defense mechanisms are unconscious psychological strategies employed by the ego to manage anxiety and internal conflicts arising from the friction between the id, superego, and reality. While Sigmund Freud introduced the concept, it was Anna Freud who systematically catalogued them in The Ego and the Mechanisms of Defence (1936). These mechanisms are universal and generally adaptive; however, their healthiness is determined by their level of maturity and flexibility.

Vaillant’s hierarchy distinguishes these mechanisms into four levels: pathological, immature, neurotic, and mature.

• Unhealthy (Immature/Neurotic) Defences: These are rigid and maladaptive. Examples include denial (refusing to accept reality), projection (attributing one's own unacceptable feelings to others), repression (pushing thoughts from consciousness), displacement (redirecting emotions to a safer target), reaction formation (expressing the opposite impulse), rationalisation (plausible but false justification) and regression (reverting to childlike behaviour).
• Healthy (Mature) Defences: These are flexible and promote social functioning. Examples include sublimation (channeling impulses into creative or productive outlets), humour (finding amusement in stress), suppression (the conscious, deliberate postponement of a thought), anticipation (realistic planning for future discomfort) and altruism (finding satisfaction in helping others).

The influence of these mechanisms on personality is profound. In the normal range, habitual defensive styles consolidate into character traits (Reich’s "character armour"), shaping an individual's vocation and moral style. For instance, a person who habitually uses sublimation may develop a highly creative personality. In the pathological range, rigid over-reliance on a single primitive defence leads to specific personality structures; for example, an exclusive reliance on projection is characteristic of the paranoid personality, while splitting is central to borderline personality patterns. Because defences are unconscious, they are hard to measure or falsify, though instruments such as the Defense Style Questionnaire attempt it.

(b) Decision heuristics; errors and biases in group decisions

Heuristics are mental shortcuts that allow for rapid decision-making under conditions of bounded rationality, a concept introduced by Herbert Simon (satisficing). Tversky and Kahneman (1974) identified several key heuristics used in individual decision-making:

• Representativeness: Judging probability by resemblance to a prototype, often leading to base-rate neglect and the conjunction fallacy (the Linda problem).
• Availability: Judging frequency by the ease with which examples come to mind, which can be skewed by recent or vivid events.
• Anchoring and Adjustment: Relying too heavily on an initial piece of information (the anchor) when making estimates.
• Framing Effect: As shown in the Asian disease problem (1981), people make different choices depending on whether a problem is framed in terms of gains or losses, a core tenet of prospect theory (1979).

Group decision-making introduces unique errors and biases:

• Groupthink (Janis, 1972): A syndrome where the desire for harmony leads to irrational decisions. Symptoms include the illusion of invulnerability, collective rationalization, and self-censorship of dissenting views.
• Group Polarisation (Risky Shift): The tendency for group decisions to be more extreme than the initial inclinations of individual members.
• Shared-information bias: Groups tend to focus on information everyone already knows rather than unique information held by individuals.
• Social loafing: A reduction in individual effort when working in a group.

Remedies for these errors include appointing a devil’s advocate, using the Delphi technique for independent input, and holding a "second-chance" meeting to allow for reconsideration.

(c) Crystallized versus fluid intelligence; ageing and memory

Fluid intelligence (Gf) and crystallized intelligence (Gc) are the two primary factors of intelligence in the Horn and Cattell Gf-Gc theory, later absorbed into the Cattell-Horn-Carroll (CHC) model built on Carroll’s (1993) three-stratum theory. Fluid intelligence refers to the ability to reason and solve novel problems independent of acquired knowledge; it is measured by culture-fair tests like Raven's Progressive Matrices and Cattell’s Culture Fair Test. Crystallized intelligence refers to the accumulation of knowledge, vocabulary, and skills acquired through experience; it is measured by verbal subtests such as those in the WAIS.

The investment hypothesis suggests that Gf is the "fuel" that is invested into learning, which then becomes Gc.

Relation to Ageing and Memory:

• Fluid Intelligence: Gf is dependent on working-memory capacity and processing speed (Kyllonen and Christal, 1990; Salthouse, 1996). It typically peaks in early adulthood and declines steadily with age as neural processing slows.
• Crystallized Intelligence: Gc is supported by semantic and procedural memory. It is generally maintained or even increases throughout the lifespan as individuals continue to acquire knowledge.

Schaie’s Seattle Longitudinal Study provided evidence for these trajectories. It is important to note that cross-sectional data can exaggerate the decline of Gf due to cohort effects (differences in education and environment between generations), whereas longitudinal studies provide a more accurate picture of individual developmental change.