“Be it agreeable or terrible, the less something is foreseen, the more does it cause pleasure or dismay. This is nowhere better illustrated than in war where every surprise strikes terror even to those who are much stronger,” Xenophon says.
Human beings generally need to be emotionally prepared in order to engage in aggressive behavior, David Grossman (On Killing) says:
The combat soldier, in particular needs to be “psyched up” for a confrontation. An attack launched at a time and place when the soldier thought he was safe takes advantage of the stress of uncertainty, destroys his sense of being in control of his environment, and greatly increases the probability that he will opt for flight (i.e., a rout) or submission (i.e., mass surrender). A highly mobile, fluid enemy who can launch surprise attacks in what the enemy believes is his rear area is particularly daunting and confusing, and the presence of such interpersonal hostility can be disproportionately destructive to the will to fight.
Viewed in another way, attacking at an unexpected and unprepared location results in the defender’s inability to orient himself. The defender’s observation-orientation-decision-action cycle, or his “OODA Loop,” has thus been stalled, and he cannot respond. Having been caught off balance, the defender panics and attempts to gain time by fleeing, or simply submits by surrendering in confusion to his assailant.
Psychological research in the area of information processing and human decision making has established a broad base of understanding of normal psychological responses to an “information overload” environment. As too much information comes in, the typical reaction is to fall back initially on heuristic, or “rule of thumb,” responses. These heuristic responses involve processes such as: “anchoring” on early information to the exclusion of later, possibly conflicting, or more accurate data; making decisions based on their “availability” or the ease with which a particular response comes to mind (e.g., repeating a recently executed maneuver); or falling into a “conformational bias” in which only information that confirms or supports the current working hypothesis is processed and contrary information is filtered out of consciousness. If these heuristic responses fail (as they are quite likely to), then the normal human response is to become trapped into a “cascading effect” in which he reacts with increasingly inappropriate actions and either fails completely (i.e., is destroyed by the enemy) or completely stops trying and falls into a paralyzed state sometimes referred to by psychologists as “learned helplessness” but always referred to by soldiers as “surrender.”
A classical example of this kind of maneuver warfare operation can be observed in Nathan Bedford Forrest’s campaign against William Tecumseh Sherman’s forces during Sherman’s march to the sea in the America Civil War. Forrest, with only a few thousand cavalry, forced Sherman to leave more than 80,000 men to guard his supply centers and is 340-mile-long supply line. On several occasions Forrest fell on unprepared units three times his size and inflicted disproportionate casualties upon his hapless enemies. His primary weapon was surprise. The rear-echelon units he was attacking were not humanly capable of maintaining a fighting pitch at all times, while Forrest’s troops entered battle having already attained “morale superiority” since they had plenty of time to prepare themselves emotionally prior to launching their surprise attacks.