The behaviorist program of infancy research has stagnated over the last decades. Ethologists and cognitivists were successful in opening up new areas for infancy research. Therefore, many authors speak of a cognitive revolution in infancy research. Nonetheless, behaviorists have convincingly demonstrated that the operant conditioning of infants is possible. As a reaction, cognitive and ethological researchers began performing conditioning research themselves and attempted to integrate this field of research into their theories. The picture of a revolution in infancy research has, thus, to be nuanced. The two camps still reject each other's basic assumptions and approach. In this respect there is discontinuity. Continuity is visible, however, in conditioning research in which we find rapprochement and co-operation between behaviorists and researchers belonging to the cognitive and ethological program.