19.5 Cognition, Language & Intelligence

19.5 Cognition, Language & Intelligence

Quick Answer: Cognition encompasses attention, perception, problem-solving, language, and intelligence. Each draws on distinct neural systems and follows principles tested on the PA-CAT.

Attention

Attention selects information for processing. Selective attention filters distracting input (the cocktail-party effect — noticing your name in a noisy room). Sustained attention (vigilance) maintains focus over time. Divided attention handles multiple tasks, limited by cognitive capacity.

Broadbent's filter theory proposed an early-selection bottleneck; Treisman's attenuation model allows weakly attended input through if semantically relevant. The Stroop effect (naming the ink color of a color-word) demonstrates automaticity and attentional conflict, engaging the anterior cingulate cortex.

Perception

Gestalt principles describe how we organize sensation into perception: proximity, similarity, closure, continuity, common fate, figure-ground. Bottom-up processing builds perception from sensory data; top-down processing uses expectations and context. Depth cues include binocular (retinal disparity, convergence) and monocular (interposition, linear perspective, relative size, texture gradient, motion parallax). Optical illusions reveal the assumptions the visual system makes.

Problem-Solving and Decision-Making

Problem-solving uses algorithms (guaranteed but slow) and heuristics (faster but error-prone). Common heuristics and biases:

• Availability — judge frequency by ease of recall; overweights vivid events.
• Representativeness — judge by stereotype; ignores base rates.
• Anchoring — over-rely on an initial value.
• Confirmation bias — seek evidence supporting hypotheses.
• Framing — choices shift with wording (gain vs loss frame).
• Functional fixedness — difficulty seeing novel uses of objects (Duncker's candle problem).

Strategies include means-ends analysis and working backward.

Dual-process theory distinguishes System 1 (fast, automatic, intuitive, heuristic — the source of most biases) from System 2 (slow, deliberate, analytical, effortful). Most everyday cognition runs on System 1; System 2 engages for novel or complex problems. Recognizing when to shift from System 1 to System 2 is a core component of critical thinking and clinical reasoning — a skill the PA-CAT rewards.

Language

Language has phonology, morphology, syntax, semantics, and pragmatics. The classic cortical model:

• Broca's area (left inferior frontal gyrus, area 44) — production. Damage → Broca's aphasia: nonfluent, halting speech with preserved comprehension.
• Wernicke's area (left superior temporal gyrus, area 22) — comprehension. Damage → Wernicke's aphasia: fluent but nonsensical speech (word salad) with impaired comprehension.
• Arcuate fasciculus connects them. Damage → conduction aphasia: preserved comprehension and fluency but impaired repetition.

Language acquisition: Chomsky proposed an innate language acquisition device (LAD) and universal grammar; children pass a critical period after which native-like mastery declines. Skinner argued language is learned via operant conditioning. Modern consensus blends both — innate readiness shaped by experience. Bilingualism does not delay language milestones; bilingual children separate phonologies early.

Language lateralization is left-hemisphere dominant in ~95% of right-handers and ~70% of left-handers. The Wernicke-Geschwind model traces language comprehension (Wernicke's) to production (Broca's) via the arcuate fasciculus. Aphasia subtypes: global (both Broca and Wernicke damaged — profound impairment), anomic (isolated naming deficit, temporal lobe), transcortical motor/sensory (spared repetition, disconnection from cortex). Dyslexia is a specific reading disability with neurobiological basis; specific language impairment (SLI) affects grammar and vocabulary despite normal intelligence. Agraphia and alexia often co-occur with aphasia.

Intelligence Theories

• Spearman's g — a general factor underlying all cognitive tasks.
• Cattell — fluid intelligence (Gf: novel problem-solving, peaks in young adulthood) vs crystallized intelligence (Gc: acquired knowledge, stable or rises with age).
• Gardner's multiple intelligences — linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal, naturalistic; influential in education though debated.
• Sternberg's triarchic — analytical, creative, practical.
• Carroll's three-stratum — g at the apex, broad abilities, narrow abilities.

IQ Testing

The Stanford-Binet and Wechsler scales (WAIS for adults, WISC for children) yield a deviation IQ (mean 100, SD 15). The normal curve places ~68% within 85–115 and ~95% within 70–130. The WAIS yields a Full Scale IQ plus index scores: Verbal Comprehension, Perceptual Reasoning, Working Memory, Processing Speed. Reliability (consistency, often Cronbach's alpha) and validity (measuring what is claimed — content, criterion, construct) govern test quality. The Flynn effect describes population IQ gains through the 20th century, likely driven by environmental factors (nutrition, education, cognitive stimulation). Tests must avoid cultural bias; heritability of IQ is substantial (twin studies estimate ~50%) but environment matters, especially in deprived settings. Intellectual disability is defined by IQ ~70 or below plus deficits in adaptive functioning, onset in the developmental period.

Cognitive Development — Piaget

Jean Piaget described four stages:

Schemas are mental frameworks; assimilation fits new data into existing schemas, accommodation revises schemas to fit new data. Vygotsky emphasized social scaffolding and the zone of proximal development; Baillargeon challenged Piaget's timing of object permanence via looking-time studies, suggesting earlier competence.