Deception is the act of misleading through the intentional concealing or misrepresentation of facts. Deception usually involves two parties: the deceiver who passes the fallacious information and the deceived, who accepts it as truth. A special form of deception is self-deception, where a person twists certain facts known to her or him. Deception is often motivated by the hope of the deceiver to gain some advantage over the deceived.
Deception that mainly involves concealing is often referred to as dissimulation. With this form of deception, some of the facts are omitted, hidden or camouflaged. For example, a person might deceive another person by hiding some fact considered a secret. Another typical example would be camouflaging, hiding, appearing in disguise, or distracting attention, so that some pertinent facts are either not visible or hidden from the deceived. The defensive mechanisms of some squids involve the ejection of a thick blackish "ink" to aid in escaping from predators.
Another important type of deception, which is often used in conjunction with the first, is called misrepresentation. With this type of deception, some of the facts are presented in a manner that obfuscates their real importance. This is done by placing the facts in a misleading context; presenting them as more or less important than they are; juxtaposing facts beside other, irrelevant facts; and/or repeating or replicating some facts as additional facts.
Deception is a tool often used in propaganda, frequently with an effort to both deceive and evoke self-deceiving mechanisms.