Should geographers regard culture and social customs as generalizations about a group of people, or should they say it comes from people's interaction with the physical environment?
There are a lot of elements that make up culture and social customs. I also think it varies a lot according to which culture we are talking about. Generalizations can be made but they may not be accurate. Different culture interact differently with their physical environment so I guess it really depends on which culture we are talking about.
That is a great question. I think that there is a strong correlation between geography and culture. This is especially strong the further you go back in time. However, it is also true today. A simple example should suffice. If you are a landlocked country, this will have serious repercussions. On the most basic level, the cost of fish will be great and shipping will be practically non-existent. If we think about shipping for a moment, and country with weak shipping will probably have a weak navy and will not be a world military power. The same can be said about land. If a country does not have good fertile land, then there will be additional problems. They will have to import all foods, etc. The same goes for natural resources such as metal, oil, etc. I think you get the point. Geography is one of the most important aspects of any country.
It may once have been possible to look at culture as an effect of the physical environment in which people lived, but I don't think you can do that anymore.
When techology was much more primitive, the physical environment mattered much more to people. Because it did, you can say that it had a lot to do with the kind of culture they ended up with.
But now we are so technologically advanced that the physical environment matters much less in terms of culture. That is, for example, why the culture of a small town in the Midwest is not that much different from that of a small town in the West even though their physical environments are very different.