Attention is thought to be a part of a larger cluster of mechanisms that serve to orient a cognitive system, to filter contents with respect to their task relevance, and to devote more computation to certain options than to others. All these activities proceed under the plausible assumption that not all information can be or ought to be processed for a system to satisfice in an ever changing world. In this paper, we describe an attention-centric cognitive system called ARCADIA that demonstrates the orienting, filtering, and resource-skewing functions mentioned above. The demonstration involves maintaining focus on cognitive tasks in a dynamic environment. While ARCADIA carries out a task, limits on its attentional capacity result in "inattentional blindness" under circumstances analogous to those where people fail to perceive otherwise salient stimuli.