Domestic cats don’t understand the reason for doors and dislike them. They are a human invention and in the cat world they would not and should not exist. Domestic cats also do not distinguish between indoors and outdoors. Domestic cats obviously recognise the difference in the landscape between indoors and outdoors but the concept of being indoors or outdoors is also a human construction.
Therefore, doors simply present a barrier to a domestic cat when he or she is patrolling his home range (his territory). Cats like to constantly patrol their home range (their home). They return to their base after patrolling. Cats like to do a brief survey of their territory. They return with information about the activities of other cats. They do this through scent marking. The scent of a cat fades over time and therefore domestic cats can assess when and where other cats have been on their territory.
As the cat likes to make a tour of duty of his territory frequently he will want to come in as soon as he has gone out but I stress, cats do not “go out and come in”; they are simply walking around their territory and the door presents a barrier.
Another reason why cats frequently like to patrol their territories is to deposit fresh scent at significant points within the boundaries of the territory to tell other cats that it is theirs and that they are present.
I don’t think that there is any other clever reason why cats want to come indoors the minute you let them out. This behaviour is simply a product of a domestic cat living in a human world full of human-made objects which are unnatural (not created by nature). Let’s remember that the domestic cat is not far, in respect of attitudes and personality, to their wild cat ancestor.
That’sa good analogy of true cat behavior. But… Sometimes, I can’t help but wonder if cats are too much like toddlers sitting in a high chair: they toss the object to the floor and enjoy watching the adults bend over and replace it. It’s a fun game. 😀
Maybe, but I think there’s more to it. Oh they don’t like doors alright, but I think it is a matter of being restricted at all. My observation has been that they don’t like to be restricted as it relates to basic survival instinct. They want unrestricted access in or out. For example: our routine here is that at dinner time, I close the back door so’s to keep them in for the night. Dinner’s being served now, however when they see the door closing they make a beeline to get out. If they make it, they’ll stand there wanting to come back in because dinner is being served. They can’t help it. It may be related to them also checking out a room they’re unfamiliar with or if something’s changes but they don’t know what yet. Like the door, they’re afraid something will change and they want to know about it. Perhaps the scent marking but I don’t see my cats marking a lot, especially in our own yard. Just a thought.
Good point, Albert, there is an element of disliking barriers which carve up their home range.