Theories of absolute identification and categorization established over past decades have revealed people’s inability to classify or judge perceived objects independently of their context. Our series of experiments shows that judged frequencies of sequentially encountered stimuli are affected by certain properties of the sequence configuration: Representations of a category do not only depend on (1) the number of stimuli/chunks in the sequence (2) the relation of the current stimulus to the immediately preceding stimulus, and (3) relations between stimuli further back versus recent stimuli but also on (4) simple sequence characteristics. Specifically, a first-run effect occurs whereby people overestimate the frequency of a given category of event when that category is the first repeated category to occur in the sequence. While current theories of absolute identification and categorization cannot account for these results, the simplicity framework, suggested in this paper, accounts for this and other context effects on judgment tasks