Chapter 1 — Variations in Psychological Attributes

IQ (Intelligence Quotient) was devised by William Stern, a German psychologist, in 1912. The formula is IQ = (Mental Age / Chronological Age) × 100. When MA equals CA, IQ is 100. A 10-year-old with a mental age of 12 has an IQ of 120.

Howard Gardner proposed eight independent types: Linguistic (fluent use of language), Logical-Mathematical (abstract reasoning and problem solving), Spatial (forming and transforming mental images), Musical (producing and manipulating musical patterns), Bodily-Kinaesthetic (flexible and creative use of the body), Interpersonal (understanding others' motives and feelings), Intrapersonal (understanding one's own feelings, motives, and desires), and Naturalistic (identifying features of the natural world).

Robert Sternberg (1985) proposed three types of intelligence: Componential (analytical) intelligence involves analysis of information and has three components — knowledge acquisition, meta (planning), and performance; Experiential (creative) intelligence uses past experiences creatively to solve novel problems; and Contextual (practical) intelligence — called 'street smartness' — involves adapting to or reshaping everyday environments.

The PASS model was developed by J.P. Das, Jack Naglieri, and Kirby (1994). It holds that intellectual activity involves three interdependent neurological units: Arousal/Attention (focusing on relevant aspects), Simultaneous and Successive Processing (integrating information simultaneously or serially), and Planning (thinking of courses of action, implementing, and evaluating them). Das and Naglieri also developed the Cognitive Assessment System (CAS) for individuals aged 5–18.

Alfred Binet was one of the first psychologists to work on intelligence. He defined intelligence as the ability to judge well, understand well, and reason well, and proposed a one-factor (uni) theory. In 1905, Binet and Theodore Simon made the first successful attempt to formally measure intelligence. The 1908 revision introduced the concept of Mental Age (MA) — a measure of intellectual development relative to one's age group. Retardation was defined as being two mental age years below chronological age.

Charles Spearman proposed the two-factor theory in 1927, using a statistical method called factor analysis. He showed that intelligence consists of a general factor (g-factor) — primary mental operations common to all performances — and specific factors (s-factors) that allow individuals to excel in particular areas such as music, architecture, or science.

According to the IQ classification table in the chapter: Above 130 is Very superior (2.2% of population), 120–130 is Superior (6.7%), 110–119 is High average (16.1%), 90–109 is Average (50%), 80–89 is Low average (16.1%), 70–79 is Borderline (6.7%), and below 70 is Intellectually disabled (2.2%). Intellectual disability has four levels: mild (IQ 55–70), moderate (35–55), severe (20–40), and profound (below 20–25).

Emotional intelligence is a set of skills that underlie accurate appraisal, expression, and regulation of emotions. The concept was first introduced by Salovey and Mayer, who defined it as 'the ability to monitor one's own and other's emotions, to discriminate among them, and to use the information to guide one's thinking and actions'. Emotional Quotient (EQ) expresses emotional intelligence in the same way IQ expresses general intelligence.

Intelligence is the global capacity to understand the world, think rationally, and use resources effectively. Aptitude refers to an individual's underlying potential for acquiring specific skills in a particular field after training. Interest is a preference for engaging in one or more specific activities relative to others. A person may have aptitude without interest, or interest without aptitude — both are needed for satisfactory performance in a field.

Indian tradition conceptualises intelligence as 'integral intelligence', emphasising connectivity with the social and world environment. The Sanskrit word 'buddhi', as described by J.P. Das, includes cognitive competence (knowledge, discrimination, understanding) along with affective and motivational components such as feelings, determined action, and self-knowledge based on conscience and will. Western cultures focus on 'technological intelligence' — skills of analysis, speed, and achievement orientation — while the Indian tradition additionally identifies social competence, emotional competence, and entrepreneurial competence as facets of intelligence.

The relationship is positive but limited. A certain level of intelligence is required for creativity, but beyond that threshold, high intelligence does not ensure creativity. Terman (1920s) found that persons with high IQ were not necessarily creative, and other research showed that both high and low creativity can be found among highly intelligent children. Creativity tests involve divergent thinking (producing a variety of ideas), while intelligence tests mainly involve convergent thinking (finding the single correct solution).

The chapter reports evidence from twin and adoption studies. Identical twins reared together correlate ~0.90 on intelligence; those reared apart correlate 0.72; fraternal twins together correlate ~0.60; siblings together ~0.50; siblings apart ~0.25. Children adopted into higher socio-economic families show increased intelligence scores. The consensus is that intelligence results from a complex interaction of heredity (nature) and environment (nurture) — heredity sets a range within which environment shapes actual development.

Yes — the NCERT PDF is completely free to read and download on this site. No account or sign-up is required.