Plain-language explanation.
Cognitive psychology studies mental processes underlying thought — how we perceive, remember, think, and understand language. It treats the mind as an information-processing system.
Core concepts and standard treatment.
Core cognitive psychology covers the information-processing model (Atkinson-Shiffrin multi-store — sensory register, STM, LTM; Baddeley working memory — central executive, phonological loop, visuospatial sketchpad, episodic buffer), memory types (explicit/declarative — episodic and semantic — Tulving; implicit — procedural, priming; levels of processing — Craik and Lockhart; encoding specificity — Tulving and Thomson; retroactive and proactive interference; forgetting curve — Ebbinghaus), attention (selective attention — Cherry cocktail party — dichotic listening; Broadbent filter; Treisman attenuation; feature integration theory; visual search — conjunction vs feature; dual-task — bottleneck theory), perception (bottom-up vs top-down; Gestalt principles — figure-ground, proximity, similarity, continuity; perceptual constancy; change blindness — Simons and Chabris), and language (Chomsky — LAD — universal grammar; Whorf — linguistic relativity; speech perception — phonemes; reading — dual-route model; aphasia — Broca vs Wernicke).
Deeper theory, debates and edge cases.
Advanced cognitive psychology covers executive functions and decision making (System 1 vs System 2 — Kahneman — dual process theory; heuristics and biases — availability, representativeness, anchoring — Tversky and Kahneman; prospect theory — loss aversion; recognition-primed decision — Klein; naturalistic decision making), cognitive neuroscience (fMRI, EEG, MEG — localisation debates; connectionist vs modular models; default mode network; hippocampus — patient H.M. — Henry Molaison; long-term potentiation — LTP — memory basis), and applied cognitive psychology (human error — Reason — Swiss cheese model — slips, lapses, mistakes; cognitive load theory — Sweller — intrinsic, extraneous, germane; Norman — Design of Everyday Things — mental models; spaced practice and retrieval practice — testing effect; cognitive interview — Geiselman — eyewitness testimony).
How it is applied in practice.
At the cognitive psychologist level, practitioners contribute to Psychological Science; lead applied research (Microsoft Research HCI; NASA Human Research Programme; Cambridge Cognition CANTAB assessment); advise on human factors (HFACS aviation safety; James Reason patient safety — NHS Improvement; nuclear control room ecological interface design — IAEA); design educational technology (Carnegie Learning intelligent tutoring; Duolingo spaced repetition; Khan Academy mastery learning); and contribute to neuropsychological assessment (WAIS-IV; Rey-Osterrieth Complex Figure; Trail Making Test; D-KEFS executive function system).