Sitting Inside Circles & Squares

It is one of the internet's favourite cat experiments: mark a square on the floor with masking tape, walk away, and wait. Sooner or later the cat arrives, considers the shape, and settles neatly inside it. No walls, no sides, no box — just a two-dimensional outline — and yet it works often enough to have become a genuine research question.

The most likely explanation is the same drive that sends cats into cardboard boxes. Enclosed spaces feel safe: they limit the directions from which something can approach, they trap a little body heat, and they satisfy a strong preference for defined, defensible resting places. A taped square appears to trip the same instinct, offering the *idea* of a boundary even though it offers no actual protection.

There is also good evidence that a visual illusion is involved. A 2021 citizen-science study led by Gabriella Smith found that cats would sit not only in real squares but in Kanizsa squares — arrangements of four 'Pac-Man' shapes whose notches trick the visual system into perceiving an square that is not physically drawn at all. Cats chose those illusory squares about as readily as real ones, which suggests they are genuinely perceiving a contour rather than simply investigating novel tape.

A quieter possibility is social. A new shape on the floor is a change in a cat's territory, and investigating changes is what cats do. Sitting on the novel object claims it, scent-marks it, and — as many owners have observed — reliably attracts the attention of whoever put it there.

Whatever the mix of causes, it is entirely benign and rather charming. If you want to try it, plain masking tape on a hard floor works best, and the cat will usually come to it in its own time rather than on demand.