When British military leaders set up a special task force in 1969 to study how best to use deception to achieve their battlefield aims, they turned their attention to the tactics used by the Israelis — not the Americans.

Formerly classified documents released Friday by the National Archives show that many officers felt the Americans didn't have a knack for deceiving the enemy. Americans were judged to be so open and friendly that they lacked cunning.

The so-called Defense Deception Advisory Group studied in detail the way Israel's military and political leaders used a complex series of intertwined deceptions to fool their Arab enemies about the Jewish state's intentions and its military capabilities.