In the introduction some remarks were made about the difficulties in applying the scientific method to the study of behaviour in humans. Especially the great individual variability and objections against types of experimentation seem to prevent a quick progress. On the other hand the branch of zoology, called ethology, is still young, which implies that generalisations are dangerous.
Nevertheless it was thought useful to present the theoretical background of ethology and to deal in a sketching way with some general lines of research circling around the causal analysis of anima! behaviour and its ontogeny. It was argued that behaviour cannot be described in terms of reflexes or reactions, but has to be considered partly as active (motivated). Information was given about the analysis of motorcoordinations, of the selectivity in perception, of motivational factors, of conflict-behaviour and of integration of behavioral elements.
Concerning the study of ontogeny of behaviour it was stated that dichotomies like 'inborn-learned' or 'instinctive-intelligent' are not fruit ful to cover the real issue, being how development of behaviour can be understood from a physiological point of view.