This paper introduces successive and coordinate intellectual thinking skills, using concepts as a best case example. The attributes and optimal presentation requirements of successive and coordinate concepts are reviewed, and types of errors commonly associated with successive and coordinate skills are delineated. The effects of both of these skills on the transfer of learning and training are also considered. Finally, a model structure is proposed that accommodates successive and coordinate relationships. Successive concepts are defined as having clearly distinguishable critical and variable attributes, whereas coordinate concepts have multiple, common critical and variable attributes. It is noted that learners, in classifying a concept, can either generalize to instances or discriminate non-instances. Two arguments are presented: successive concept learning should focus on generalization skill development, or the use of examples-only as an instructional strategy; and, since coordinate concepts emphasize both generalization and discrimination, they are better learned through the use of matched sets of examples and nonexamples. It is concluded that a matrix is a useful model structure that could provide for increasing discrimination along one axis and increasing generalization along the other axis. (32 references) (Author/DB)