In 1992 Arcady A. Putilov, a researcher in Animal and Human Physiology, published a paper empirically testing Chizhevsky hypothesis analyzing events described in Soviet historical handbooks. Putilov found that the frequency and "polarity" of events, including revolution, is the highest in the years of the solar cycle maximum and the lowest in the year before the minimum. In 1996 professor of psychology Suitbert Ertel (University of Göttingen) corroborated a "substantial" relationship between solar activity and revolutionary behavior through statistical analysis of a "Master Index of Violence from Below" (MIVE) for the period 1700–1985 CE.