Part One of this paper summarizes six years of investigations devoted to the study of the influence that a variable called teacher "wait-time" has on development of language and logic in children taking part in elementary science programs. It discusses the relation of wait-time to 10 outcome variables. Wait time at two locations was studied in natural settings and in experimental settings to determine how location and duration of pauses influence the outcome variables. It was noted, in addition, that there is an interaction between wait-time and rewards and that students rated at the top or at the bottom of a class receive differential treatment with respect to these variables. A heuristic which relates wait-time and rewards to language, logic, and fate control is introduced. It will be discussed in more detail in Part Two of this paper. Part two, published in v58 n4 of this journal describes the relation between pauses, rewards, and fate control. (Contains 7 figures and 1 table.)