Source: "The Social Guidebook to Norway"
Norwegians tend to have their friendships organised in social bubbles
Each of these social bubbles is linked to a particular activity, place or time in a Norwegian's life
Norwegians will even introduce their friends by referring to which social bubble they belong to
Ungdomsskolevenner, videregåendeskolevenner, universitetsvenner, hyttevenner, Birkengjengen, fotballgjengen, dansegruppe, foreldregruppe, barselgruppe, symøtegjengen, naboen, etc
They will meet friends from one group at any given time, and only friends from that one group
Norwegians have many social bubbles, but these bubbles nearly never mix
It is not allowed to invite an outside into a bubble if the outsider has not taken part into the activity around which the bubble was created.
You cannot invite outsiders, nor can you meet with just part of the group
This can go as far as if you made a girlfriend in a year under yours at university, and you meet the friends from your class two years after you are done studying, it may not be natural nor expected that you invite your girlfriend to join as she was not part of the group when the social bubble was formed. This applies even if she knows everyone in the group very well and for many years. Had she been in the same class, and not a year younger, she would of course be invited.
All of this to say that if you just came to Norway, do not be surprised if you are not invited to join in.
You need to register by yourself in different activities, take part into the activities over many months, contribute to the group, and then you will be part of a social bubble and be invited to all the things these people do.
But remember that you cannot invite other people to join into the bubble, they need to take part into the activity first.
«Om du vil bli med å ta en øl med Birken-gruppen må du gå Birken først!»
If the activity does not anymore take place - Birkengruppe 1999, ungdomskolevenner, venner fra fadderuke - Then you will never be able to join the group or the social activities around the group
In my lectures and courses I call this the "rigidness of social bubbles".
Read more about our amazing Norwegian friends in Our Social Guidebooks to Norway (også tilgjengelig på norsk "Nordmenn uten filter")