Perception

How sensory information is organized and interpreted to represent the environment — from low-level visual processing through object recognition and auditory scene analysis.

Vision

  • Color Perception — How the visual system interprets wavelength information to produce the experience of color.
  • Motion Perception — Detection and interpretation of movement in the visual field.
  • Visual Illusions — Systematic misperceptions that reveal the constructive nature of visual processing.
  • Depth Perception — The ability to perceive three-dimensional distance using binocular and monocular cues.
  • Binocular Depth Cues — Depth information derived from the slight difference between the two eyes' images.
  • Monocular Depth Cues — Depth information available from a single eye, including perspective, occlusion, and texture gradients.
  • Object Recognition — Identifying objects by matching sensory input to stored representations.
  • Face Perception — Specialized processing for detecting and identifying human faces using holistic and configural coding.
  • Feature-Matching Theories — Models proposing that recognition proceeds by comparing stimulus features to stored templates.
  • Recognition-by-Components (RBC) Theory — Biederman's theory that objects are recognized by decomposing them into volumetric primitives called geons.

Visual Anatomy

Eye & Retina
  • Retina — The light-sensitive neural tissue lining the back of the eye that converts photons into neural signals.
  • Cones — Photoreceptors concentrated in the fovea that mediate color vision and high-acuity daylight sight.
  • Rods — Photoreceptors specialized for low-light vision, abundant in the peripheral retina.
  • Fovea — The central pit of the retina where cone density peaks and visual acuity is highest.
Visual Pathway
  • Optic Nerve — The bundle of retinal ganglion cell axons that carries visual information from eye to brain.
  • Lateral Geniculate Nucleus — The thalamic relay station that routes retinal signals to primary visual cortex.
  • Primary Visual Cortex (V1) — The first cortical area to process visual input, mapping orientation, spatial frequency, and contrast.
Cortical Visual Areas
  • Ventral Stream — The 'what' pathway projecting from V1 to temporal cortex for object and face recognition.
  • Dorsal Stream — The 'where/how' pathway projecting from V1 to parietal cortex for spatial processing and action.
  • Area V4 — A ventral-stream region critical for color constancy and intermediate form processing.
  • Area MT/V5 — A dorsal-stream region specialized for motion direction and speed processing.

Perceptual Organization & Theories

  • Gestalt Principles — Laws of perceptual grouping—proximity, similarity, continuity, closure—that describe how elements are organized into wholes.
  • Gestalt Approach — The theoretical framework emphasizing that perception is organized into wholes that differ from the sum of parts.
  • Figure-Ground Perception — The process of separating a visual scene into a foreground figure and a background.
  • Figure-Ground Segregation — Mechanisms that assign border ownership and distinguish figure from ground in ambiguous displays.
  • Perceptual Constancy — The tendency to perceive objects as stable in size, shape, and color despite changes in sensory input.
  • Signal Detection Theory — A framework for separating an observer's perceptual sensitivity from response bias in detection tasks.
  • Change Blindness — Failure to notice large changes in a visual scene when they coincide with a brief disruption.
  • Constructive Perception — The view that perception actively builds a representation by combining sensory data with prior knowledge.
  • Top-Down Theories — Models emphasizing the role of expectations, context, and knowledge in shaping perception.
  • Bottom-Up Theories — Models emphasizing that perception is driven primarily by incoming sensory data.

Hearing

  • Auditory Perception — How the auditory system processes sound waves into perceived pitch, loudness, and timbre.
  • Speech Perception — Specialized processing of acoustic signals into phonemes, words, and meaning.
  • Music Cognition — Cognitive processes involved in perceiving, producing, and responding emotionally to music.
  • Auditory Scene Analysis — Bregman's framework for how the brain segregates overlapping sound sources into distinct streams.
  • Phonemic-Restoration Effect — The illusion of hearing a missing phoneme when it is replaced by noise in a known word.
  • Categorical Perception — The phenomenon of perceiving continuous acoustic variation as discrete phonetic categories.

Touch

  • Somatosensory Perception — Processing of touch, temperature, pain, and proprioception through skin and body receptors.

Smell

  • Olfactory Perception — The sense of smell—how airborne molecules are transduced into odor percepts.

Taste

  • Gustatory Perception — The sense of taste—detection of sweet, sour, salty, bitter, and umami via tongue receptors.

Multisensory Processing

  • Multisensory Integration — How the brain combines information from multiple senses into a unified perceptual experience.

Attention

The mechanisms that select, filter, and sustain focus on relevant information — including selective attention, visual search, and the cognitive limits that shape awareness.

Types of Attention

  • Selective Attention — The ability to focus on relevant information while ignoring distractors.
  • Divided Attention — The capacity to process multiple tasks or information streams simultaneously.
  • Sustained Attention — The ability to maintain focus on a task over an extended period.
  • Exogenous Attention — Involuntary, stimulus-driven orienting triggered by sudden or salient events.
  • Endogenous Attention — Voluntary, goal-directed orienting guided by expectations and task demands.
  • Vigilance — Sustained readiness to detect rare, unpredictable signals over long time periods.

Selective Attention

  • Bottleneck Theories — Models proposing that information processing is limited at a specific stage, creating a bottleneck.
  • Filter Theories — Broadbent's and Treisman's models of how irrelevant information is blocked or attenuated early in processing.
  • Cocktail Party Problem — The challenge of selectively attending to one voice among many competing conversations.
  • Automatic Processes — Well-practiced operations that require minimal attention and run without conscious control.
  • Automatization — The transition from effortful, controlled processing to fast, automatic performance through practice.

Attentional Phenomena

  • Inattentional Blindness — Failure to perceive a fully visible object when attention is engaged elsewhere.
  • Attentional Blink — A brief period after detecting one target during which a second target is often missed.
  • Stroop Effect — Interference that occurs when automatic word reading conflicts with color naming.
  • Cocktail Party Effect — The ability to detect personally relevant information, such as one's name, in an unattended channel.
  • Inhibition of Return — Slower responses to a previously attended location, biasing attention toward novel locations.

Models & Theories

  • Filter Theory of Attention — Broadbent's early-selection model proposing that unattended input is filtered based on physical features.
  • Feature Integration Theory — Treisman's theory that focused attention binds separate features into unified object percepts.
  • Biased Competition Model — A neural model in which attended objects win competitive interactions among cortical representations.
  • Attentional Control Theory — Eysenck's framework linking anxiety to impaired goal-directed attentional control.
  • Multiple Resource Theory — Wickens' model proposing separate pools of attentional resources for different modalities and codes.

Visual Search

  • Visual Search — The perceptual task of scanning a display to find a target among distractors.
  • Pop-Out Effect — Effortless, parallel detection of a target defined by a single unique feature.
  • Conjunction Search — Slow, serial search required when a target is defined by a combination of shared features.
  • Guided Search Model — Wolfe's model in which top-down activation guides attention to likely target locations.
  • Feature Search — Rapid, parallel detection of targets differing from distractors in one basic feature.

Memory

How information is encoded, stored, and retrieved — spanning sensory registers, working memory, long-term systems, forgetting, and the reconstructive nature of recall.

Memory Systems

  • Sensory Memory — Ultra-brief storage of raw sensory input—iconic for vision, echoic for audition.
  • Short-Term Memory — A limited-capacity store holding information for seconds without rehearsal.
  • Working Memory — An active system for temporarily maintaining and manipulating information in service of cognition.
  • Long-Term Memory — The vast, relatively permanent store of knowledge and past experience.
  • Episodic Memory — Memory for personally experienced events situated in a specific time and place.
  • Semantic Memory — Organized knowledge about words, concepts, and facts independent of personal experience.
  • Procedural Memory — Implicit memory for skills and habits acquired through practice.

Working Memory Components

  • Iconic Store — The visual sensory register that briefly holds a high-capacity snapshot of the visual field.
  • Phonological Loop — The working-memory component that maintains speech-based information through sub-vocal rehearsal.
  • Visuospatial Sketchpad — The working-memory component that maintains and manipulates visual and spatial information.
  • Central Executive — The attentional control system of working memory that coordinates subsidiary systems.

Encoding & Storage

  • Levels of Processing — Craik & Lockhart's framework: deeper semantic processing produces more durable memories than shallow processing.
  • Elaborative Rehearsal — Encoding strategy that links new information to existing knowledge for stronger memory traces.
  • Semantic Encoding — Processing the meaning of information, yielding the most durable form of encoding.
  • Self-Reference Effect — Enhanced memory for information related to oneself compared to other encoding strategies.
  • Keyword Method — A mnemonic linking a foreign word to a similar-sounding keyword via a mental image.
  • Pegword Method — A mnemonic system pairing numbered rhyming pegs with items to be remembered.
  • Chunking — Grouping individual items into larger meaningful units to expand effective working-memory capacity.
  • Elaborative Interrogation — A study strategy of generating explanations for why stated facts are true.
  • Narrative Chaining — Linking items into a coherent story to exploit the memorability of causal and temporal sequences.
  • Analogies & Metaphors — Using structural comparisons to map new information onto familiar domains for deeper understanding.
  • Concept Mapping — Diagramming relationships among concepts to organize and visualize knowledge structure.
  • SQ3R — A study method—Survey, Question, Read, Recite, Review—designed to promote active reading.
  • Schema Theory — The idea that memory is organized around knowledge structures that guide encoding and retrieval.
  • Dual Coding Theory — Paivio's theory that information encoded both verbally and visually is remembered better.
  • Memory Consolidation — The gradual process by which fragile new memories are stabilized into lasting long-term traces.
  • Procedural Knowledge — Know-how knowledge for performing skills, often implicit and difficult to verbalize.

Retrieval

  • Recall — Retrieving information from memory without external cues, as in essay or free-recall tests.
  • Recognition — Identifying previously encountered items from a set of alternatives.
  • Recall vs. Recognition — The comparison of generative retrieval (recall) with discriminative retrieval (recognition).
  • Encoding Specificity — Tulving's principle that retrieval succeeds best when cue context matches encoding context.
  • Tip-of-the-Tongue Phenomenon — The state of knowing a word exists in memory but being temporarily unable to retrieve it.
  • Tip-of-the-Tongue Phenomenon — The frustrating feeling of almost-but-not-quite retrieving a known word from memory.

Forgetting

  • Proactive Interference — Previously learned material impairs the learning or recall of new material.
  • Retroactive Interference — Newly learned material disrupts the recall of previously learned material.
  • Decay Theory — The hypothesis that memory traces fade over time when not accessed or rehearsed.
  • Forgetting Curve — Ebbinghaus's finding that retention drops steeply at first, then levels off over time.
  • Interference Theory — The view that forgetting results from competition among similar memories rather than simple decay.
  • Retrieval-Induced Forgetting — Selectively practicing some memories inhibits retrieval of related, unpracticed memories.

Memory Disorders

  • Anterograde Amnesia — Inability to form new long-term memories after the onset of brain damage.
  • Retrograde Amnesia — Loss of memories formed before the onset of brain damage, often temporally graded.
  • Infantile Amnesia — The near-absence of autobiographical memories from the first few years of life.

Special Topics

  • False Memories — Remembering events that never occurred, often induced by suggestion or imagination.
  • Flashbulb Memory — Vivid, confident memories for the circumstances of learning about shocking events.
  • Prospective Memory — Remembering to carry out intended actions at an appropriate point in the future.
  • Autobiographical Memory — The personal memory system encompassing episodic recollections and the life narrative.
  • Eyewitness Memory — Memory for witnessed events, susceptible to distortion by post-event information and leading questions.
  • Memory and Emotion — How emotional arousal enhances memory consolidation while sometimes impairing peripheral details.
  • Mnemonic Devices — Techniques that use organization, imagery, or association to improve encoding and retrieval.
  • Memory Palace — A spatial mnemonic in which items are mentally placed along a familiar route for later retrieval.
  • Method of Loci — The ancient technique of associating items with locations in a well-known spatial layout.

Problem Solving

Strategies and obstacles in reaching goals — from algorithmic and heuristic approaches to mental set, functional fixedness, and insight.

  • Problem Solving — The cognitive process of finding a path from an initial state to a goal state.
  • Means-End Analysis — A strategy that reduces the difference between current and goal states through sub-goal decomposition.
  • Mental Set — The tendency to apply a previously successful strategy even when a simpler solution exists.
  • Functional Fixedness — Inability to see an object's novel use because of fixation on its conventional function.
  • Incubation Effect — Improvement on a problem after a period of not consciously working on it.
  • Algorithms — Step-by-step procedures that guarantee a correct solution if followed completely.
  • Heuristics — Mental shortcuts that simplify decisions but can lead to systematic errors.
  • Insight — The sudden realization of a solution, often accompanied by an 'aha!' experience.

Creativity

The cognitive processes behind generating novel and useful ideas — including divergent and convergent thinking, mental models, and metacognition.

  • Creativity — The ability to generate ideas that are both novel and appropriate to a given context.
  • Divergent Thinking — Generating many varied solutions to an open-ended problem.
  • Convergent Thinking — Narrowing possibilities to find a single best answer to a well-defined problem.
  • Mental Models — Internal representations of external reality used to reason about situations and predict outcomes.
  • Dual-Process Theory — The distinction between fast, intuitive System 1 and slow, deliberate System 2 reasoning.
  • Metacognition — Awareness and regulation of one's own cognitive processes—thinking about thinking.

Reasoning

How people draw conclusions from evidence — covering deductive, inductive, analogical, causal, and conditional reasoning.

  • Deductive Reasoning — Drawing logically certain conclusions from given premises, as in syllogistic reasoning.
  • Inductive Reasoning — Inferring general principles from specific observations or instances.
  • Analogical Reasoning — Solving new problems by mapping structural relations from a familiar source domain.
  • Causal Reasoning — Identifying cause-and-effect relationships from covariation, temporal order, and mechanism.
  • Conditional Reasoning — Evaluating if–then statements, studied through tasks like Wason's selection task.

Historical Timeline

Major milestones in the development of cognitive psychology as a scientific discipline.

1879

Wilhelm Wundt establishes the first experimental psychology laboratory at the University of Leipzig, marking the formal beginning of psychology as a science.

1885

Hermann Ebbinghaus publishes On Memory, introducing the forgetting curve and nonsense-syllable methodology for studying learning and retention.

1890

William James publishes The Principles of Psychology, distinguishing primary memory (short-term) from secondary memory (long-term) and describing the stream of consciousness.

1932

Frederic Bartlett publishes Remembering, introducing schema theory and demonstrating the constructive nature of memory retrieval.

1956

George Miller publishes “The Magical Number Seven,” establishing capacity limits of short-term memory. The same year, Bruner, Goodnow, and Austin publish A Study of Thinking.

1958

Donald Broadbent publishes Perception and Communication, proposing the filter model of selective attention and launching the information-processing approach.

1960

Newell and Simon develop the General Problem Solver. Miller, Galanter, and Pribram publish Plans and the Structure of Behavior, applying computational ideas to cognition.

1967

Ulric Neisser publishes Cognitive Psychology, giving the field its name and establishing it as a distinct discipline.

1968

Atkinson and Shiffrin propose the multi-store model of memory, distinguishing sensory, short-term, and long-term stores.

1972

Craik and Lockhart propose the levels-of-processing framework. Tulving distinguishes episodic from semantic memory.

1974

Baddeley and Hitch propose the working memory model. Tversky and Kahneman publish “Judgment under Uncertainty: Heuristics and Biases.”

1980

Treisman and Gelade publish Feature Integration Theory, establishing the distinction between parallel feature search and serial conjunction search.

1983

Michael Posner introduces the spatial cueing paradigm, becoming a standard tool for studying covert attention.

2002

Daniel Kahneman receives the Nobel Prize in Economics for prospect theory and work on heuristics and biases, bringing cognitive psychology to global prominence.

Key Researchers

Foundational and contemporary figures whose work has shaped the field.

Founding Figures

  • Wilhelm Wundt — Founded the first experimental psychology laboratory (1879) and established psychology as an independent science through systematic introspection.
  • William James — Author of The Principles of Psychology (1890); distinguished primary and secondary memory and described the stream of consciousness.
  • Hermann Ebbinghaus — Pioneered the experimental study of memory (1885) with nonsense syllables, discovering the forgetting curve and spacing effect.

Cognitive Revolution

  • Ulric Neisser — Published Cognitive Psychology (1967), naming the field and establishing it as a distinct discipline.
  • George Miller — Demonstrated the capacity limits of short-term memory in “The Magical Number Seven” (1956).
  • Noam Chomsky — His review of Skinner’s Verbal Behavior (1959) challenged behaviorism and catalyzed the cognitive revolution in linguistics and psychology.
  • Herbert Simon — Co-developed the General Problem Solver with Newell (1960) and introduced the concept of bounded rationality.
  • Donald Broadbent — Proposed the filter model of selective attention in Perception and Communication (1958), launching the information-processing approach.

Memory & Learning Researchers

  • Endel Tulving — Distinguished episodic from semantic memory (1972) and formalized the encoding specificity principle.
  • Alan Baddeley — Proposed the working memory model with Hitch (1974), replacing the unitary short-term store with a multi-component system.
  • Elizabeth Loftus — Demonstrated the misinformation effect and the malleability of eyewitness memory, transforming understanding of false memories.
  • Fergus Craik — Co-created the levels-of-processing framework (1972), showing that deeper encoding produces stronger memories.

Attention & Perception Researchers

  • Anne Treisman — Developed Feature Integration Theory (1980) and discovered illusory conjunctions, transforming understanding of visual attention.
  • Michael Posner — Introduced the spatial cueing paradigm (1980) and mapped the neural networks underlying attentional control.
  • Roger Shepard — Demonstrated mental rotation (1971), providing evidence that mental imagery preserves spatial properties of physical objects.

Judgment & Decision Making

  • Daniel Kahneman — Developed prospect theory and dual-process theory with Tversky; received the Nobel Prize in Economics (2002) for work on heuristics and biases.
  • Amos Tversky — Co-developed the heuristics and biases research program with Kahneman, identifying availability, representativeness, and anchoring heuristics.

Developmental Psychologists

  • Jean Piaget — Proposed the stage theory of cognitive development (sensorimotor through formal operational), shaping developmental psychology for decades.
  • Lev Vygotsky — Introduced the zone of proximal development and emphasized the social and cultural foundations of cognitive development.

Games

Interactive experiments that let you experience classic cognitive psychology effects first-hand.