• leaders;
  • complexity;
  • communications

Integrative complexity reflects the degree to which the source of a communication perceives several dimensions and points of view relevant to the topic (differentiation) and the degree to which such characteristics are seen as related to each other (integration). During international crises, bilateral decreases in the integrative complexity of communications frequently precede the outbreak of war; a unilateral decrease reliably precedes surprise strategic attacks. In the current study, complexity was scored in the messages of selected leaders from before to approximately a month after the terrorist attacks of 11 September 2001. Even this limited database replicated some of the complexity patterns found previously, as well as showing some novel characteristics. This was the first application of the method to hostilities other than inter–nation or civil wars.