The Stalinist system came to Russia 90 years ago and with it the frequent belief in manifestly untrue assertions. This practice has been more pronounced in some periods than in others. It has been denounced on various occasions by experts, but it has by no means been rejected. If in recent years there has been increased sympathy, even a certain longing, for the Stalin period in Russian history, it should not be surprising that this includes the readiness to believe manifestly untrue assertions. President Putin himself argued not long ago that Stalin was no worse than Oliver Cromwell.

According to ISIOM and other leading Russian public opinion polls, almost 50 per cent of Russians took a positive view of Stalin in 2008/9, and their number has certainly not gone down since. This does not mean that that all aspects of Stalin's rule are considered desirable, but an excess of anti-Stalinism is frowned upon by the authorities and the schoolbooks have been adjusted accordingly. It does mean, however, that certain psychological attitudes which were prevalent in the Stalin era have again become acceptable, even desirable.

This includes the belief in conspiracies, perhaps even a predilection for this genre, in order to explain past and present events. But this mindset alone cannot account for the present trends. How to explain the fact that quite often deliberate falsehoods are sincerely believed?

This fascinating phenomenon has been observed and described by neurologists, psychiatrists and psychologists for a long time. It is known as clinical confabulation. It was first described in 1889 in amnesic patients by a leading Russian psychiatrist, Sergei Korsakoff (1854-1900), and is known in contemporary medicine as the Wernicke-Korsakoff syndrome. Korsakoff graduated from school with a gold medal, the highest distinction in Russian schools, and studied medicine in Moscow and Vienna. He observed what some call "invented memory"; others have used the term "honest liars" with regard to some of their patients.

This issue has been intensively studied in recent decades, when medicine and psychology have become increasingly interested in problems of memory. To give a recent clinical example: On a Monday morning in a home for the elderly, a nurse in Cologne, Germany, asked 73-year-old Mr K about his weekend. "Oh, my wife and I flew to Hungary and we had a wonderful time," he replied. The nurse paused, for Mr K's wife had died five years earlier and he had not left the home in months. Was he trying to impress her? More likely Mr K was confabulating, a phenomenon in which people describe and even act upon false notions they believe to be true. (Maria Dorothea Heidler, "Is your brain lying to you?", American Scientist, March 2014.)

Research on clinical confabulation has shown that there are various types of the phenomenon, that those who suffer from it present their stories in great detail, usually with absolute conviction, and will not reconsider their narrative even if faced with rational argument. Those engaged in confabulation research also found that it was frequently caused by some form of brain damage resulting in the deficiency of vitamin B1. (Korsakoff first thought that alcoholism was the most frequent cause.) But on the whole there has been no unanimity with regard to the causes of this condition, probably because it has appeared as the result not of one specific injury or disease but through a variety of causes.