Glossary

The ability to name the pitch of a note heard on its own, with nothing to compare it against

Sleep-promoting neuromodulator that accumulates during wakefulness; caffeine works by blocking its receptors.

The price developers pay to use an LLM from their programs, set by the number of tokens they have it read and write.

The duration for which a person can maintain focused concentration on a task

A 200-500ms period after detecting one target during which a second target is frequently missed, revealing temporal limits of attention allocation.

Brain-Derived Neurotrophic Factor. A protein promoting neuronal survival, growth, and synaptic plasticity, with secretion increased by aerobic exercise

A test that has many LLMs solve the same problems with fixed answers and compares their ability by measures such as the share answered correctly.

When benchmark questions or answers end up in a model's training data, so its score comes out higher than its real ability.

The unit for the size of a musical interval: one hundredth of a semitone, with 1200 cents to an octave

Having an LLM write out the intermediate steps toward an answer, not just the answer, which tends to help with multi-step problems.

The time to select the correct response from multiple options based on stimulus identity, incorporating cognitive decision-making into reaction speed.

Performance failure under pressure caused by excessive self-monitoring that disrupts automatized skilled movements.

An individual's preference for morning or evening activity, in which clock gene polymorphisms are thought to play a part.

The approximately 24-hour internal clock governing sleep-wake and cognitive cycles

Standard deviation divided by mean expressed as a percentage, measuring response consistency independent of absolute speed.

Systematic deviations from rational judgment caused by heuristic processing shortcuts in the brain.

The total amount of mental effort being used in working memory at a given time

The ability to maintain cognitive function despite brain structural damage, built through education, occupation complexity, and intellectual stimulation

A reduced ability to distinguish between certain colors due to cone cell variations

A range of values within which the true score likely falls, quantifying the measurement error inherent in all cognitive tests.

The upper limit on how much text an LLM can read at once in a single request, covering both the documents you pass in and the answer it returns.

The ability to detect luminance differences between adjacent areas, more fundamental than visual acuity for predicting real-world visual performance.

A stress hormone released from the adrenal cortex that temporarily enhances energy and alertness but causes hippocampal and prefrontal cortex damage when chronically elevated

The ability to draw on knowledge, vocabulary, and procedures accumulated over time and put them to use

Structured practice targeting specific weaknesses with immediate feedback, operating outside the comfort zone and distinct from mere repetition.

A neurotransmitter involved in reward prediction, motivation, and motor control that modulates prefrontal cortex working memory via D1 receptors

A working memory training task requiring simultaneous tracking of two stimulus streams

The ability to perceive detail in moving objects, distinct from static visual acuity and critical for sports, gaming, and driving performance.

Mechanisms that change gene expression without altering DNA sequence, where exercise, sleep, and stress modify gene activity through DNA methylation and histone modification

A way of writing instructions that shows a few example answers in the prompt to convey the form and criteria you want.

A mathematical model predicting movement time based on target distance and size that defines the speed-accuracy tradeoff in motor control

A mental state of complete absorption in an activity, with altered time perception

The ability to find a rule on the spot in an unfamiliar problem and reason it through without leaning on stored knowledge

When an LLM states something untrue in plausible, natural sentences; no model brings this to zero.

The ability to synchronize visual input with motor output for precise movements

Variation in time intervals between heartbeats where higher HRV indicates greater autonomic flexibility and stress resilience

Seahorse-shaped brain structure essential for memory formation and spatial navigation, highly plastic yet vulnerable to stress.

A rating that turns votes, cast by people who compare answers from two LLMs and pick the better one, into a score for how often a model is chosen.

The ability to suppress prepotent or automatic responses, a core executive function mediated by the prefrontal cortex.

A relative index that rescales the result of a standardized intelligence test so the same-age population averages 100

The point up to which an LLM's training text was collected; the model does not know about events after it.

The wait from sending a question to getting an answer, seen as time to the first character and the speed of the flow.

A large-scale language model that learns how words fit together from vast amounts of text and produces answers and writing by predicting what comes next.

The state in which the gap between two values falls within the wobble that chance in measurement can create, so neither can be called higher.

A sleep-promoting hormone secreted by the pineal gland that is suppressed by blue light and regulates the circadian sleep-wake cycle

A pre-structured set of motor commands stored in the basal ganglia that can be executed as a unit without conscious control.

An LLM's ability to read or produce not only text but other kinds of data, such as images, audio, and video.

The process by which repeated motor actions become automatic through practice

Fatty insulation layer around nerve axons that increases signal conduction speed 50-100x through saltatory conduction.

The brain's ability to reorganize its structure and function through experience

An LLM whose weights, the core of the model, are published, so you can run it on your own computer or server.

A statistical measure indicating the percentage of scores that fall below a value

The perceptual work of noticing that two notes differ in pitch; the smallest detectable gap is the discrimination threshold

Performance improvement driven solely by expectation, mediated by endogenous dopamine release in reward circuits.

Score improvement from repeated test exposure rather than true ability change, typically saturating after 3-5 attempts for most cognitive tests.

The brain region behind the forehead responsible for executive functions including planning, decision-making, and inhibitory control.

The rate at which cognitive operations are executed, a fundamental intelligence component that declines with age but responds to training.

The whole text of instructions and questions you give an LLM; the mix of instructions, material, constraints, and format shapes the answer.

A method of finding documents related to a question before an LLM answers, having it read them, and basing the answer on what they say.

The best-known measure of non-verbal reasoning, in which the examinee selects the figure that belongs in a blank cell of a matrix of shapes

The interval between a stimulus and the initiation of a response

An LLM built to write out its intermediate thinking at length before giving an answer, which costs extra time and money for the thinking.

The ability to compare two notes and judge how far apart they are

A rapid eye movement that shifts the fixation point, occurring 3-4 times per second and determining visual information acquisition efficiency

The time to respond to a single predetermined stimulus with a single response, representing the purest measure of sensorimotor speed.

Transient post-awakening cognitive impairment caused by residual slow-wave activity in the prefrontal cortex, with a duration that depends on the sleep stage before waking

The inverse relationship between response speed and accuracy where faster responses increase errors and slower responses improve precision.

Interference that occurs when conflicting stimuli slow response time

Having an LLM answer in a fixed form such as JSON, so the result can be used directly in tables and programs.

An instruction placed before the user's questions that sets the role, tone, and prohibitions, and applies to the whole conversation.

A setting for how much an LLM's answers vary; low gives the same answer, high gives a wider range of answers.

The correlation between scores when the same person takes the same test on different occasions, indicating measurement stability.

The smallest unit an LLM uses to read and write text; prices and how much the model can read at once are also set by this count.

The visual area from which information can be extracted in a single glance without eye movements, shrinking with aging and cognitive load.

The progressive decline in sustained attention performance over time, typically becoming pronounced after 15-20 minutes of continuous monitoring.

The brain's system for interpreting and responding to visual information

A cognitive system for temporarily holding and manipulating information

A standard metric for measuring typing speed based on word count per minute

The inverted-U relationship between arousal level and performance, where moderate arousal produces optimal cognitive output.