Google's search operator AND - operators

Question

I am trying to figure out how exactly google's search operator AND works for an application that I am currently building.
I found this article:
https://supple.com.au/tools/google-advanced-search-operators/
that says that google uses AND operator as a default operator when searching
however I am trying some examples and this doesn't seem to be the whole story
For example, when I search for:
Google search term: perth tourism sea surfing
it gives me more search results than:
Google search term: perth tourism sea
How is that possible, I would expect that AND operator would narrow the search results not increase them (this is what I would expect from an OR operator)
Any ideas of why this is happening?

Answer 1

Check this resource out: https://www.webpagefx.com/blog/google-2/google-advanced-search-operators-cheat-sheet/
I have a feeling the default behaviour is and/or, but I am somewhat speculating.
You could incorporate some quotes such as perth tourism "sea surfing" but I might try something such as allintext: perth tourism sea surfing. That would be more machine-friendly than worrying about where to include quotes. Quotes may also constrain the order of your keywords. For example, "I like cats" will find an exact match (and not return pages with I cats like).
Additionally, I think you might not be using AND as it is documented on the site you linked.
The AND operator functions with the same logic as an AND operator - similar to the OR operator, it must be in all CAPS to work. Google will look for all conditions to be met before returning any results.
e.g. site:twitter.com AND intitle:SuppleSolutions AND inurl:Saijo_George where all the 3 conditions should be satisfied for Google to return any result.
Your search terms should probably be:
perth AND tourism AND sea AND surfing
You could add to your logic to replace the search string's characters with AND but before that, I would probably see if allintext: perth tourism sea surfing is viable.

Answer 2

Apparently I think that it is a problem of personalization and localization
I did the following things:
1. I open an incognito window
2. I signed out from all google accounts
3. I opened google.com rather than google.xx using www.google.com/ncr
4. I searched "perth" AND "tourism" AND "sea" and "surfing"
which seems to narrow down the results from searches with less terms.