The three objectives of this study were: (1) To investigate the changes in different teaching behaviors effected by different instructions alone, training alone and the interaction between them when they are combined; (2) To reveal the structure of interrelations among classroom activities, classified according to two category observation systems, Flanders Interaction Analysis Categories (FIAC) and Technion Diagnostic System (TDS), in different situations; and (3) To check empirically the assumptions underlying these two category observation systems in a peer teaching situation. Smallest Space Analysis was used to reveal the structure of intercorrelations among classroom activities in a 2 X 2 factorial design. It was shown that instructions cause a change in the interrelation structure while training does not. The relationship among classroom activities showed a two-dimensional porex pattern where joint direction for FIAC and TDS was student initation. Lateral direction was affective vs. instrumental for FIAC; knowledge vs. analytical and creative thinking for TDS. (Author/RC)