Cats Don't Care If A Square is Imaginary, They'll Sit on it Either Way

Cats' brains seem to fill the gaps in the Kanizsa square illusion, just like humans.
Derya Ozdemir

Those who have enjoyed the COVID-19 quarantines can be divided into two groups: introverts and pets. Since our "outside-times" turned inside out, many had the opportunity to spend quality time with their pets, and in came the interesting projects and better yet, scientific studies starring our feline friends. 

A new study, affectionally named "If I fits I sits: A citizen science investigation into illusory contour susceptibility in domestic cats", carried out during the COVID-19 pandemic has found that cats' love for enclosed spaces such as cardboard boxes and laundry baskets extends to even imaginary squares. 

The study's key goal — which is now published in the journal Applied Animal Behaviour Science — was to learn more about the cats' visual perception by seeing whether they are capable of perceiving an illusory square in the same way they would a physical one.

The trials explained:

In order to see whether domestic cats are susceptible to illusory contour, animal cognition researcher Gabriella Smith, a recent master’s graduate from Hunter College in NY, and her colleagues asked pet owners to become citizen scientists: They would create various shapes including the typical square and Kanizsa square illusion — four Pacman-like shapes placed in the corners trick our brains into seeing a square — for the cats using paper, scissors, and tape. A similar Kanizsa shape without the illusory effect was used for the control. 

Cats Don't Care If A Square is Imaginary, They'll Sit on it Either Way
The shapes. Source: Gabriella Smith

After the shapes were laid on the floor, the cats would let into the room as the owners recorded them without performing any interactions. This would take six days.

The findings

Of the 500 participants, 30 owners completed the experiment, and nine cats actually corporated by making a choice at least once during the experiments. Cats sat eight times on the square, seven times on the square-like illusion, and once on the control.

While the sample size is small, this suggests cats are drawn to boxes, even when they are illusory. As for the Kanizsa square, it seems like cats' brains fill in the gaps just like humans.

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"The major takeaways are that cats are susceptible to the Kanizsa illusion in a human-like way, and are most likely attracted to 2D shapes for their contours (sides), rather than solely novelty on the floor," Smith told Gizmodo in an email. "Furthermore, this study illuminates how cats are great candidates for citizen science: They have so many quirky behaviors that are just waiting to be harnessed to study their cognition!"

Smith has shared the stimuli and instructions, so if you'd like to test your cat's love for squares, you might want to try them out.