By Emma Young
The world is not exactly short of videos from cute cats to weird antics. But a specific series of videos collected from cat owners during a COVID-19 lockdown reveals something really interesting: a famous optical illusion that makes us fools is getting cats too. The Citizen Science project, which experimented cats in their own four walls, shows that they too are being tricked by “Kanizsa squares,” an illusion that suggests the presence of a square that actually doesn’t exist.
It is known that cats love to sit like boxes in enclosed spaces. They even like to sit in square shapes made of duct tape, as documented during a Twitter craze in 2017 (#CatSquare). So in the new study published in Applied behavioral research for animalsGabriella E. Smith of the City University of New York and colleagues went a step further to see if cats also prefer illusory squares.
Of the 500 cats and owners who signed up to participate, 30 completed all attempts. The owners “were never aware of the purpose of the study at any time before or during the experiment,” the authors write. (Well, at least they weren’t told what it was about.)
Every day for six days each owner put their cat out of the room while they stuck some charms on the floor. The researchers instructed them to use two out of three stimuli each day: an actual square, a Kanizsa square (in which four Pacman cutouts are arranged to suggest the lines of a square), and the Kanizsa control (in which the Pacman -like cutouts point in the other direction.)
The owner then put on sunglasses (so his cat couldn’t use its gaze as a clue of what to do), brought the cat into the room, and started the video. If your pet was sitting or standing in one of the molds within five minutes, the process ended. In both cases, they submitted the result after five minutes.
Of the 30 cats that completed all experiments, nine cats chose a stimulus at least once and a total of 16 times. On eight of these occasions a cat sat in a seat. At seven o’clock it was sitting in a Kanizsa square. In contrast, the Kanizsa control was chosen only once. This suggests that cats treat the Kanizsa squares like real ones. Like us (and indeed dogs, chimpanzees and many other animals) they show “susceptibility to illusory contours”.
Clearly, there are several drawbacks to recruiting animal owners to conduct experiments on your own. Very few of those who signed up actually completed the full study. Also, the lighting levels in the different houses could have been very different, and this could have influenced the cats’ choices, the team notes. However, there are good reasons to examine cats in their own home rather than in a laboratory. Because they are more relaxed at home, their behavior is likely to be more natural.
The study provides further evidence that animals experience all kinds of illusions. But there are also other insights into cat cognition that have received little attention compared to dogs. Why not is not clear. However, given the useful, albeit limited, data from this new study, the researchers write, “Using citizen science as a preliminary stage to cat-recognition studies in the laboratory could bridge this gap significantly.”
– If I fit, I sit: A civil science study on the susceptibility to illusory contours in domestic cats (Felis silvestris catus)
Emma Young (@EmmaELYoung) works at BPS Biomedarticles