Last Updated on September 3, 2026 by admin
Your cat looks at you, lets its eyelids drift halfway down, holds them there, and then lets them fall shut for a beat. That is a slow blink sequence. It is not a sleepy cat.
Most owners file it under contentment and stop there. The cat is warm, the cat is fed, the cat is doing its melting-ice-cream face.
Fair enough. But that reading treats the blink as a byproduct instead of something the cat is aiming at you.
It is aimed at you.
What the movement actually is
In 2020, a team at the University of Sussex ran the first experiment testing whether the slow blink works as two-way communication between cats and people. Their paper in Scientific Reports breaks the movement into parts: a run of half-blinks, where the lids move toward each other without ever meeting, followed by either a prolonged narrowing of the eye or a full closure.
In the first experiment, 21 cats from 14 households sat in their own living rooms while their owners slow-blinked at them from about a metre away. The control was the same owner in the same room, simply not interacting.
Cats produced significantly more half-blinks and more eye narrowing when the owner was blinking at them.
Then the split nobody expects. Male cats roughly doubled their half-blink rate between the control and the blinking condition. Female cats barely moved.
The stranger test
The second experiment used 24 cats and an experimenter they had never met, who deliberately avoided the cats beforehand.
She offered a flat palm, withdrew it, then either slow-blinked at the cat for a minute or held a neutral face with her gaze angled slightly away. Then the hand went out again.
Cats were more willing to approach the stranger’s hand after the slow blink than after the neutral face. A modest effect, but a real one, and it held with a person the cat had no relationship with at all.
The shelter finding
Here is the part that changes what you do with this.
A companion study at Cats Protection’s National Cat Adoption Centre in Sussex, published in the journal Animals, filmed 18 shelter cats being slow-blinked at through the glass door of their pens. Researchers then tracked how many days each cat waited before someone reserved it.
The cats that closed their eyes fully were reserved sooner. Not the half-blinkers. Not the eye-narrowers. The full closers.
Both how often a cat closed its eyes and how long it held them shut correlated with a shorter wait for a home.
The strange part: cats did not close their eyes more in response to being slow-blinked at. Eye closure was the one movement in the whole sequence that did not reliably increase. It was also the only one that predicted adoption.
The authors’ reading is that a full closure lasts longer and reads louder to a person standing at a pen door. It is the movement a stranger notices and files as this one likes me.
Lead author Tasmin Humphrey and Professor Karen McComb point out in the paper that adopters describe choosing a cat almost entirely in terms of connection. We clicked. The cat chose us.
Why cats do it at all
The Sussex team offers two possibilities and commits to neither.
One: slow blinking began as a way to interrupt an unbroken stare, which reads as a threat in most social animals, and got elaborated once cats moved in with us. Two: humans read slow blinking as friendly, reward cats for doing it, and cats learned.
Whether the behaviour is evolved or learned is still open. The researchers say so directly.
How to do it properly
Sit about a metre away. Wait until the cat makes eye contact. Narrow your eyes the way you would in a relaxed smile, then let them close for a couple of seconds. Repeat.
Do not stare between blinks. The Sussex team revised their own control condition partway through after pilot trials suggested a direct, unbroken stare from an unfamiliar human may be read as threatening.
If you volunteer at a shelter, or you are meeting a cat you are thinking of taking home, it costs nothing. The Cornell Feline Health Center keeps a broader library on feline behaviour if you want the rest of the vocabulary that goes with it.
One caveat the authors state plainly: the shelter sample was 18 cats at a single centre, and they call the finding tentative.
Still. Eighteen cats, one glass door, and the ones who shut their eyes went home first.
Does your cat slow-blink back at you? Tell us in the comments 👇