# Decision Science > [!info] Gateway page > Second most-linked page in the vault. Orientation lives here; the full discipline — several hundred pages of mental models, biases, fallacies and heuristics — lives at [[Decision Science Hub]]. Decision science is the interdisciplinary study of how choices actually get made, as opposed to how a fully rational agent would make them. It sits at the intersection of cognitive psychology, behavioral economics, statistics, and game theory, and its organizing insight is that human judgment is not merely noisy — it is **systematically** biased in directions that can be predicted, measured, and exploited. That last word is why this discipline occupies so much of a knowledge base about political power. The gap between how people reason and how they think they reason is not a curiosity; it is a resource. Every mature propaganda operation is, functionally, an applied decision science program. The techniques catalogued under [[Disinformation]] and [[Propaganda]] work because they target specific, documented failure modes: the availability heuristic makes vivid anecdotes outweigh base rates, motivated reasoning makes disconfirming evidence *strengthen* prior belief, and the illusory truth effect makes repetition itself feel like evidence. None of these require the audience to be foolish. They are the ordinary operating characteristics of a mind built for speed. The field's modern shape comes from the Kahneman–Tversky program of the 1970s, which replaced "people are irrational" with something far more useful: people run **heuristics** — fast, frugal rules that are usually adaptive and predictably wrong in specific conditions. Prospect theory formalized the asymmetry that losses hurt roughly twice as much as equivalent gains feel good, which explains more about political messaging than any amount of ideology does. Loss-framed appeals — *they are taking this from you* — outperform gain-framed appeals almost everywhere, and restorationist politics is loss framing all the way down. The vault splits the material into four working layers, and knowing which layer you're in prevents most confusion: **Cognitive biases** are the documented failure modes — [[Confirmation Bias]], [[Availability Heuristic]], and the wider psychology-of-misjudgment catalogue drawn from [[Charlie Munger]]. These describe what goes wrong. **Mental models** are the deliberate correctives — transferable frames borrowed from other disciplines and used as thinking tools. Roughly 455 pages live under [[Mental Models Hub]], with [[Mental Models Hub]] serving as a reverse index that routes from *situation* to *model* rather than from model to definition. If you only use one entry point in this discipline, use that one. **Logical fallacies** are the reasoning failures that show up in argument rather than in private judgment — the rhetorical surface of the same underlying machinery. See [[Logical Fallacies Hub]]. **Game theory** is the strategic layer: what happens when the other side is also reasoning, and knows you are. Coordination problems, commitment devices, and credible threats explain institutional behavior that looks irrational from the outside. See [[Game Theory Hub]]. A caution worth internalizing before you go further. The bias literature is unusually easy to weaponize as a way of dismissing people you disagree with — *they only believe that because of motivated reasoning*. Applied honestly, the discipline cuts inward first. The reason it earns its place here is not that it explains the other side; it is that it constrains your own confidence, and gives you a vocabulary precise enough to say what specifically went wrong in a piece of reasoning instead of just registering that something did. ## Where to go from here | Destination | What's there | |---|---| | [[Decision Science Hub]] | The full landscape: Kahneman–Tversky, the four layers, key figures, essential works | | [[Mental Models Hub]] | **Start here for practical use** — reverse index from situation to model | | [[Mental Models Hub]] | The models themselves, organized by source discipline | | [[Logical Fallacies Hub]] | Reasoning failures in argument | | [[Game Theory Hub]] | Strategic interaction and commitment | | [[Behavioral Economics]] | The economics-side branch | | [[Confirmation Bias]] · [[Availability Heuristic]] | The two biases most load-bearing for media analysis | ## See also [[Psychology]] · [[Propaganda]] · [[Disinformation]] · [[Information Warfare]] · [[Economics]]