Why Do Cats Lay On Paper?

Is it a warmth thing?

Partly. Paper, even at room temperature, provides a slight insulating layer between the cat and a cooler surface like a hardwood floor or a desk. Cats are extremely sensitive to temperature differences and actively seek out surfaces that are even marginally warmer. A single sheet of newspaper on a cold floor creates a micro-environment that's detectably warmer than the floor itself. It's a subtle difference, but cats notice it.

Is it about texture?

Paper has a unique feel under a cat's paws and body: smooth, slightly crinkly, and different from the surfaces around it. Cats are drawn to novel textures, and a flat piece of paper on a floor or desk stands out as something distinct. This also explains why cats sit on laptops (warm and textured), books (different from the table), and blankets (soft and insulating). If it's different from the surrounding surface, a cat will investigate by sitting on it.

Are they trying to get your attention?

Absolutely, and this is probably the biggest factor when it comes to papers, books, and laptops you're actively using. Cats learn very quickly that sitting on the thing you're focused on redirects your attention to them. It works every single time, which is why they keep doing it. It's not spite or jealousy; it's effective attention-seeking behavior refined through repetition. Your cat wants to be involved in whatever you're doing, and planting themselves on your work is the most direct way to make that happen.