Denmark is the only major developed country where social trust has substantially increased since measurement began: from 47% in 1979 to 76% in 2008, converging with the high levels of trust in Norway and Sweden. Here’s something else: Germany borders Denmark and shares many cultural and institutional features with it, but German social trust in 2008 was 39%. So what could account for a difference over over 35 points? This 2012 paper suggests that the difference is due to greatly differing degrees of political stability. Denmark simply saw far less political instability during this time period.
My theory is that social trust is grounded in the observation of compliance with social norms.* If political instability generates more observable norm violations, or undermines stable norms, then the capacity to learn to trust other is greatly limited.
So here’s a thought: perhaps Denmark would ordinary have social trust levels at Scandinavian levels but trust was suppressed through somewhat less political stability and because of its proximity to Germany, whose recent institutional history is quite chaotic. Once Germany stabilized, Danish trust could converge with other countries.
This may suggest that German social trust should gradually approach Scandinavian social trust, and it might be at similar levels if not for Nazism, division under communism, and a difficult reintegration period. We don’t see that in the data yet, but that might be because social trust in East Germany remains low.
*The authors seem to agree. They say that the “stable ‘underlying rock’ of social trust in any society, including a political stability secured by formal institutions that are firmly embedded in shared norm” (355)).