Cyclic population fluctuations of small rodents are characteristic in northern and central Fennoscandia. In Finland research addressing this problem was initiated in 1940s by professor Olavi Kalela, and the work is carried on by his co-workers and their students. One of the paramount questions is to what extent and by which ways social interactions among individuals contribute to the observed population dynamics. The focus at Konnevesi Research Station has - during its whole ten years of existence  -  been on social mechanisms of small rodents. This article is a review of our pending studies. It rather soon turned out that population cycles take place in spite of stabilising social mechanisms, not because of them. Our studies uncovered correlation between social organisation and quality of food and habitat. This led to comparisons between species and among populations, calling for experimental research both in large outdoor enclosures and in detailed laboratory tests. The questions studied were the effect of familiarity of interacting individuals on population growth and spacing behaviour, comparison of dispersal patterns between Microtus and Clethrionomys, and the effects of odours of conspecific and heterospecific rodents and of predators on the reproduction of individual voles. Quite recently we have focused on predator-prey interactions between rodents and their main predators, mustelids and raptors. Results of these studies imply that behaviour of voles exhibits great phenotypic plasticity as response to changing environment.