Last reviewed on April 24, 2026.
The field of cognitive science spans many disciplines, and it comes with its own terminology. Use this glossary to look up basic definitions and refresh your memory on important concepts. The definitions are intentionally brief; follow the links in the text for more detailed explanations.
- Cognition
- Mental processes involved in acquiring, storing and using knowledge.
- Perception
- The interpretation of sensory information to form a coherent picture of the world.
- Attention
- The process of selectively focusing on certain stimuli while ignoring others.
- Memory
- The capacity to encode, store and retrieve information.
- Working Memory
- A limited capacity system for temporarily holding information available for processing.
- Long‑Term Memory
- Stores information over extended periods, including semantic, episodic and procedural memory.
- Learning
- The acquisition of knowledge or skills through experience, study or teaching.
- Language Acquisition
- The process by which humans learn to understand and produce language.
- Artificial Intelligence
- Computer systems designed to perform tasks requiring human‑like intelligence.
- Neural Network
- A computational model composed of interconnected units that process information in parallel.
- Connectionism
- An approach to modelling cognition using networks of simple units analogous to neurons.
- Representation
- A mental symbol or model that stands for information about the world.
- Embodied Cognition
- A view that cognition depends on the body’s interactions with the environment.
- Cognitive Bias
- A systematic deviation from rational judgement or decision making.
- Heuristic
- A simple rule or strategy used to make judgements or decisions quickly.
- Cognitive Architecture
- A unified theory or model describing the fixed structures and processes of cognition.
- Phonology
- The study of the sound systems of languages.
- Syntactic Parsing
- The process of analysing the grammatical structure of a sentence.
- Functional Magnetic Resonance Imaging (fMRI)
- A brain imaging technique that measures changes in blood flow to infer neural activity.
- Electroencephalography (EEG)
- A method that records electrical activity from the scalp to study brain function.
- Psycholinguistics
- The study of how humans comprehend, produce and acquire language.
- Cognitive Neuroscience
- The study of the neural mechanisms underlying cognitive processes.
- Metacognition
- Awareness and regulation of one’s own thinking and learning processes.
- Encoding
- The process of transforming sensory input into a form that can be stored in memory.
- Retrieval
- The process of accessing stored information when it is needed.
- Schema
- An organised mental structure that summarises what a person knows about a category of objects, events or relations.
- Semantic Memory
- Memory for general facts and meanings, independent of when or where they were learned.
- Episodic Memory
- Memory for specific personally experienced events, including their time and place.
- Procedural Memory
- Memory for how to perform skills and actions, often expressed without conscious recollection.
- Theory of Mind
- The ability to attribute mental states — beliefs, desires, intentions — to oneself and others.
- Executive Function
- A set of high-level processes that control attention, working memory and goal-directed behaviour.
- Embodiment
- The view that the body shapes cognition through its sensory and motor interactions with the world.
- Predictive Processing
- A framework in which the brain continually generates predictions about incoming input and updates them based on prediction error.
- Bayesian Inference
- A statistical approach in which beliefs are updated by combining prior probabilities with new evidence; used as a model of perception, learning and decision-making.
- Reinforcement Learning
- Learning to choose actions that maximise reward, used both as a psychological theory and as a class of machine-learning algorithms.
- Symbolic AI
- An approach to artificial intelligence that represents knowledge using discrete symbols and explicit rules.
- Deep Learning
- A subfield of machine learning that uses neural networks with many layers to learn representations from data.
- ACT-R
- A cognitive architecture developed at Carnegie Mellon University that models cognition as a set of interacting modules for perception, memory and action.
- Aphasia
- A language disorder, usually caused by brain injury, that affects production, comprehension or both.
- Dual-Process Theory
- The proposal that judgement and reasoning rely on two systems: a fast, automatic process and a slow, deliberate one.
- Framing Effect
- A bias in which the way a choice is described changes which option a person prefers, even when the underlying outcomes are equivalent.
- Salience
- The property of a stimulus that makes it stand out from its surroundings and capture attention.
- Magnetoencephalography (MEG)
- A non-invasive imaging method that measures magnetic fields produced by neural activity, with high temporal resolution.
- Transcranial Magnetic Stimulation (TMS)
- A technique that uses magnetic fields to temporarily disrupt neural activity in a targeted region, used to test the causal role of that region in a task.
How to read these definitions
The entries above are intentionally short — a definition is meant to anchor a term, not to substitute for an explanation. The notes below give a little more context on the clusters of terms that newcomers find most slippery, and link to the longer articles on the site that go further.
Memory is not one thing
It is tempting to treat memory as a single capacity, but the field has long distinguished several stores and several processes. Working memory is the small, fast store that holds the contents of the current task — a phone number you are about to dial, the start of a sentence you are still reading. Long-term memory is much larger and includes semantic memory (facts and meanings), episodic memory (specific experiences) and procedural memory (skills). Each kind of memory depends on partly different brain systems, and each is supported by different encoding and retrieval processes. The article on memory and learning goes into how each type develops and decays.
Attention is not one thing either
Like memory, attention is a family of related processes. Selective attention filters the world; divided attention coordinates several streams; sustained attention keeps a focus over time; alternating attention shifts deliberately between tasks. The control of attention can be top-down (goal-driven) or bottom-up (driven by salience). Saying that someone "has trouble with attention" is rarely specific enough to be useful — the more interesting question is which kind of attention. The article on attention and perception works through the distinctions.
Representation, the bridge concept
Most theories in cognitive science share a working assumption: minds carry representations — internal stand-ins for things in the world. The disagreements are about what kind of representations they are. Symbolic AI treats representations as discrete tokens that are combined according to rules. Connectionism treats them as patterns of activation distributed across many simple units. Embodied cognition argues that some representations are not abstract at all but are grounded in sensory and motor experience. Different traditions answer different questions well; reading across them is more rewarding than choosing a side early.
Methods come in pairs
The methods in this glossary tend to trade off two things: spatial resolution (where in the brain something happens) against temporal resolution (when it happens). fMRI shows where with millimetre precision but lags behind neural activity by seconds. EEG and MEG follow neural activity in milliseconds but blur the location. TMS and lesion studies, by contrast, are not just measurement tools — they let researchers test whether a region is causally necessary for a function, not merely correlated with it. The article on research methods explains how studies often combine techniques to get the best of more than one.
Bias, heuristic and rationality
The terms heuristic, cognitive bias and dual-process theory are often run together. They are related but not the same thing. A heuristic is a strategy — a shortcut. A bias is a systematic departure from a normative standard, often produced by a heuristic. Dual-process theories propose that biases arise when fast, automatic reasoning takes over from slow, deliberate reasoning. None of this implies that intuition is always wrong: in many real-world settings the heuristic is well-calibrated to the environment. The article on decision making and biases walks through the most common ones and the conditions under which they bite.
This list is not exhaustive, and the field is constantly evolving. For more depth on any term, follow the linked articles or browse the blog.