Making sense of the environment

Selective attention focuses on one stimulus among many; the cocktail-party effect is hearing your name across a noisy room (proof that unattended input is still monitored). Divided attention is multitasking (poor for effortful tasks). Inattentional blindness (missing an obvious stimulus while focused elsewhere — the "invisible gorilla") and change blindness show how much we fail to notice without attention.

Thinking uses mental representations (concepts, prototypes — the most typical example of a category, and schemas — organized knowledge frameworks). To solve problems we use algorithms (step-by-step methods guaranteeing a solution) or faster heuristics (mental shortcuts that usually work but can mislead). Insight (sudden solution) and trial and error are other strategies. Barriers include mental set (sticking to a familiar approach) and functional fixedness (seeing an object only in its usual use).

Fluid intelligence is reasoning and solving novel problems (declines with age); crystallized intelligence is accumulated knowledge and skills (stable/rises with age). Spearman's general intelligence (g) vs. Gardner's multiple intelligences and Sternberg's triarchic theory (analytical, creative, practical). Note variables in intelligence: heritability, the Flynn effect (rising scores over generations), and environmental/SES influences.

Children build schemas and adapt them by assimilation (fit new info into an existing schema) and accommodation (change the schema to fit new info). The stages:

• Sensorimotor (0–2): experiences the world through senses/actions; achieves object permanence.
• Preoperational (2–7): symbolic thinking and language, but egocentrism and no conservation.
• Concrete operational (7–11): logical thinking about concrete events; masters conservation.
• Formal operational (11+): abstract and hypothetical reasoning.

Also know Vygotsky (development driven by social/cultural interaction; the zone of proximal development and scaffolding) as the contrast to Piaget.

The circadian rhythm is the ~24-hour biological clock (regulated by the suprachiasmatic nucleus and melatonin). Sleep cycles through stages, tracked by EEG:

• Awake — beta waves (alert) give way to alpha waves (relaxed, eyes closed).
• NREM 1 — light sleep, theta waves, hypnagogic jerks.
• NREM 2 — sleep spindles and K-complexes.
• NREM 3 — deep slow-wave sleep, delta waves; restorative.
• REM — rapid eye movement, vivid dreaming, paradoxical sleep (brain active, body paralyzed).

Dream theories: activation-synthesis (dreams are the cortex interpreting random brainstem activity) vs. consolidation/memory and Freud's wish-fulfillment. Know major sleep disorders (insomnia, narcolepsy, sleep apnea, night terrors). Psychoactive drugs by class: depressants (alcohol, barbiturates, benzodiazepines — slow CNS), stimulants (caffeine, nicotine, cocaine, amphetamines — speed CNS, raise dopamine), opiates/narcotics (heroin, morphine — pain relief, euphoria), and hallucinogens (LSD, marijuana). The brain's reward pathway (dopamine, nucleus accumbens, mesolimbic pathway) underlies addiction.

Encoding can be automatic or effortful; the levels-of-processing effect says deeper (semantic) encoding remembers better than shallow. The classic store model:

• Sensory memory — brief, large-capacity (iconic ~visual, echoic ~auditory).
• Short-term / working memory — ~7±2 items for ~20–30s; working memory (Baddeley) actively manipulates info. Chunking and rehearsal extend it.
• Long-term memory — effectively unlimited; split into explicit (declarative) — episodic (events) and semantic (facts) — and implicit (nondeclarative) — procedural (skills) and conditioned responses.

Retrieval uses recall vs. recognition, aided by priming, context-dependent and state-dependent cues, and the serial position effect (primacy + recency). Forgetting: encoding failure, decay, interference (proactive = old disrupts new; retroactive = new disrupts old), and retrieval failure. Memory is reconstructive: the misinformation effect and source monitoring errors distort it (Loftus). Neural basis: the hippocampus (forming explicit memories), amygdala (emotional memories), cerebellum (procedural), and long-term potentiation (LTP) (the cellular basis of learning). Dysfunction: Alzheimer's, Korsakoff's syndrome, and anterograde vs. retrograde amnesia.

Building blocks: phonemes (smallest sound units), morphemes (smallest meaning units), semantics (meaning), syntax (grammar/word order), and pragmatics (social context). Acquisition theories: Skinner (learning/reinforcement), Chomsky (nativist — an innate language acquisition device and universal grammar), and the interactionist view (biology + social interaction). The Whorfian (linguistic relativity) hypothesis holds that language shapes thought — its weak form (linguistic relativity) says language influences thought; its strong form (linguistic determinism) says language determines/limits it (the strong form is largely rejected). Brain areas: Broca's area (speech production — Broca's aphasia is broken/effortful speech) and Wernicke's area (comprehension — Wernicke's aphasia is fluent but meaningless speech); damage to the connecting fibers causes conduction aphasia.