Emotions exert a profound influence on cognitive processes, both the fundamental processes mediating cognition, such as attention and memory, and higher-level processes including decision-making and learning. A number of emotion effects on cognition have been identified, but their mechanisms are not yet understood. In this paper I describe a methodology for modeling the effects of emotion on cognition, within a symbolic cognitive-affective architecture. The primary objective of the approach is to facilitate the construction of alternative mechanisms of observed emotion effects. The paper describes how the effects of anxiety are modeled and how alternative mechanisms of these effects can be explored.