Eastern Europe survived World War II with many times killed military and civilian deaths from war and war-related causes than any other country - a devastating per capita toll not experienced by nations other than Germany and perhaps Italy, the two main aggressors.
The deaths were reflected in population statistics and also in the balance of males to females which suffered greatly.
Historically, men had initiated courtship and were most openly 'choosers' and 'aggressors' in the mating game.
However, the inbalance of males reflected by military being predominately male coupled with huge deaths in the military caused the inbalance to swing wildly toward large number of females chasing a large lacunae of males.
The result isthat mating habitschanged.
Over time in the USSR with its 15 constituent Republics together with those nations that eventually became 'satellites'(exceptGermany) there was great pressure on young women to pursue males with far greater pressure than historially in those nations.
World trends against great modesty and keeping females 'in their place' fell somewhat in the post-war world. Coupled with a paucity of males, the young marriage-aged woman who sought to reproduce had to be more forward, and that apparently has led to greater female pressure shown to potential male mates to demonstrate their 'interest' and at the same time to keep males feeling in their bodies and minds which many accomplished by keeping physically close to potential mates they had chosen as well as more continually admitting interest as well as continually admitting and showing to the male their interest.
In short, far less 'coyness' and manners and far more willingness of females to show their interest, often in public to show that interest while disregarding social pressure that demanded women be 'indiscreet' and not public in showing their interest in mating.
The result: Far greater expression of interest in mating as demonstrated, in part, by showing far more interest in their availability when with a group of men and in
their chosen man' when one had been singled out.
The Result: Greater Public Displays of Affection, a war-caused phenomenon.