This paper discusses the creation of analytic categories that were applied to behavior in quite different, contrasting settings and that at the same time retained their ecological validity. In Project Follow Through, behavior stream observations were conducted on 20 second-grade children for an entire school day. To study the structure of behavior streams over time, a set of categories was constructed to look at "phase cognitive functioning," or the functions of cognition relative to the main task over successive phases of the behavior stream. In the Secondary Education Through Health (SETH) program, educationally disadvantaged high school seniors spent two mornings a week in a hospital work setting. The technique that evolved for observing the SETH program was a Setting and Behavior Instrument, which refers to functioning with people, data, and things in a particular setting. The data collection procedures used in these two studies represent different ways of defining higher and lower level cognitive functioning and different methods of observing and analyzing their natural occurrences. Between them, the studies appear to confirm the fruitfulness of examining the environmental conditions under which different levels of cognitive functioning occur. (BW)