Games : How Can I Stop Game From Stopping After 3 or 4 Social Policies?

I get the icon saying adopt a policy and I do, but after I adopt the first 3 or 4 that are unlocked, the game will not progress and I'm stuck where I am. No more turns, no more production.

I am new to the game and being there is no real manual to consult, I am at a loss.

Do I have to adopt a Social Policy when icon appears or can I ignore until later in game?