In peace, societies are more open to outside influence. In wartime the enemy cultures are heavily antagonized, and a societies unique characteristics are heavily emphasized, as was the case during the cold war in Russia. After it was largely finished, Russians openly embraced american pop music, Starbucks, and McDonald's. The society is just more vulnerable to foreignization. If the US had absolutely no foreign enemies, our economy would thrive but our society would change because Chinese and middle eastern society would be openly embraced and our uniqueness would dwindle. Of course the economy would naturally thrive in peacetime, so if you consider them the same thing, then culture would just be more prone to change, which is fine in our culture.
No, I do not believe that societies stagnate in times of peace. I actually believe that the exact opposite is true. When there is no war or conflict to worry about, a country can turn their attention to the finer things in life. I think that peace time is generally when music and art blossoms. I think that it also frees a country up to spend money on infrastructure. Countries exhibit more productivity in general during peace times.
In times of peace countries and society in general can be open. The push for a better culture is going to thrive when there are zero aggressors. .In times of war, technology may be pushed to boundaries as a whole,but you can't really base everything on that. It safe to say that artistic values get expressed more at peace time, and so does medicine.
No, societies do not stagnate in times of peace, because peacetime is when societies grow. Things do not grow during times of war. In fact, in the United States, the 1920s and the 1950s were two of the most economically successful periods, and these were peaceful periods. An economy cannot grow if its people are busy thinking about wars.
During times of peace is when societies become more artistic and expressive and start to thrive all together, as long as there isn't too much corruption in place. But it doesn't compare to the scientific advancements during times of way or conflict. But no, they do not stagnante at all.
No, societies flourish in times of peace. When financial and material resources need to be shipped to another location to support troops, the companies and individuals who need those financial resources on the home-front do not receive them. The government does not have the money or manpower to create new jobs, explore new energy sources, ensure youth have sufficient educational opportunities, and perform other tasks necessary for growth.