The Slow Blink: What Science Says About the Secret Language Cats Use to Say "I Love You"
Research Blog | MustLovePets
You're sitting on the couch. Your cat is across the room, watching you with that half-lidded, ancient gaze that every cat owner knows. Then, slowly, their eyes close — just for a moment — and reopen. You probably smiled when it happened. But did you know that tiny movement was a message? A deliberate one, backed by actual science?
The cat slow blink — sometimes called a "cat kiss" or "eye kiss" — is one of the most well-documented yet under appreciated forms of communication in the human-animal world. And research published in 2020 confirmed what cat lovers had long suspected: it's real, it's intentional, and you can do it back.
Here's everything you need to know about the science of the slow blink — and how to use it to deepen your bond with your cat.
What Is a Slow Blink, Exactly?
A slow blink is a specific facial expression in cats characterized by a gradual half-close and reopen of the eyes, sometimes accompanied by a momentary full closure. It's distinct from a regular blink — it's deliberate, unhurried, and often paired with a relaxed body posture.
Cat behaviorists have observed slow blinking for decades as an apparent signal of comfort and positive affect. In cat-to-cat communication, prolonged direct eye contact is generally a sign of threat or tension. Narrowing and closing the eyes is the opposite — a visible withdrawal of that threatening gaze, a signal that says: I am not a threat. I feel safe. I trust you.
When a cat slow blinks at you, they're doing the same thing. They're choosing not to maintain the hard stare — choosing softness over alertness — in your presence.
The Research That Changed Everything
For years, the slow blink was discussed mostly in the world of cat behavior enthusiasts, cat trainers, and veterinary behaviorists. It wasn't until 2020 that it received rigorous scientific attention.
Leanne Proops, Kristyn Grounds, Amy Victoria Smith, and Karen McComb at the University of Portsmouth and the University of Sussex published a landmark study in Scientific Reports titled "Direct communication from domestic cats to their owners."
The study consisted of two experiments.
Experiment 1: Can Cats Recognize a Human Slow Blink?
In the first experiment, 21 cats were tested in their own homes (reducing stress and confounding variables). Owners were asked to sit opposite their cat at a set distance and, on a signal, perform a slow blink sequence — a series of relaxed eye narrowings and closures.
The result? Cats were significantly more likely to slow blink back at their owners after the owner slow blinked compared to when the owner held a neutral, non-blinking expression.
The cats weren't just reacting to random eye movements. They recognized the slow blink as a specific communicative signal — and they responded in kind.
Experiment 2: Does It Work with Strangers Too?
The second experiment took it further. This time, an unfamiliar researcher (not the cat's owner) either slow blinked at the cat or maintained a neutral face. After the slow blink sequence, the researcher extended a hand toward the cat.
Two findings stood out:
Cats slow blinked more at researchers who had slow blinked at them — even though the researcher was a stranger.
Cats were significantly more likely to approach the researcher after slow blinking, compared to cats who received the neutral gaze.
This is remarkable. The slow blink didn't just work as a recognition signal between bonded pairs — it actively built a bridge with an unfamiliar human. The researchers concluded that slow blinking is a genuine cross-species positive communication signal, and one that humans can initiate to put cats at ease.
The study's lead author, Leanne Proops, described it plainly: "It's a great way of communicating with your cat. Try narrowing your eyes at them as you would in a relaxed smile, followed by closing your eyes for a couple of seconds. You'll find they respond in kind and you can start a sort of conversation."
Why Cats Evolved This Signal
To understand why the slow blink works, it helps to understand how cats navigate threat and trust.
Cats are both predators and prey — a combination that makes them exquisitely sensitive to the body language of others. Hard, sustained eye contact in the feline world is a dominance or threat signal. It's how cats stare each other down before a confrontation.
Conversely, looking away, narrowing the eyes, or closing them entirely communicates the opposite: I'm not challenging you. I'm relaxed. I have no aggressive intent.
This is why cats often seem to "choose" the one person in the room who isn't looking at them — the person who's allergic, or the one who's ignoring them. From the cat's perspective, that person is displaying all the right non-threatening body language. The sustained, well-meaning stares of eager cat lovers, meanwhile, can register as intense.
The slow blink — eyes narrowing, softening, briefly closing — is essentially the ultimate display of non-threat. When your cat slow blinks at you, they're telling you they feel no need to be vigilant around you. That's not just affection in a human sense. That's trust at a biological level.
A Note on Oxytocin
Research on the cat-human bond has also found that positive, voluntary interactions between cats and their owners are associated with elevated oxytocin — the same "bonding hormone" involved in parent-infant attachment, friendship, and romantic love.
A 2019 study published in Current Biology by Kristyn Vitale (then at Oregon State University) found that cats are securely or insecurely attached to their owners in patterns that mirror infant attachment to caregivers — and that cats actively seek proximity to their owners as a secure base when stressed.
The slow blink almost certainly operates within this attachment system. It's not a performative trick — it's a window into a cat's felt sense of safety and connection with you.
How to Slow Blink at Your Cat (And Actually Do It Right)
The good news: this requires no special equipment and very little practice. Here's how to make it work.
Step 1: Choose the right moment.
Slow blinking works best when your cat is already calm — resting, sitting quietly, watching you from a comfortable spot. Don't try it when your cat is alert, agitated, or mid-play. The signal only registers in a relaxed context.
Slow blinking works best when your cat is already calm — resting, sitting quietly, watching you from a comfortable spot. Don't try it when your cat is alert, agitated, or mid-play. The signal only registers in a relaxed context.
Step 2: Let them notice you.
Make soft eye contact first. Don't stare intensely — just let your gaze land on them naturally.
Make soft eye contact first. Don't stare intensely — just let your gaze land on them naturally.
Step 3: Perform the slow blink sequence.
Slowly narrow your eyes (like a relaxed smile), hold that squint for a beat, then let your eyes close gently for about a second. Reopen slowly. Repeat the sequence once or twice.
Slowly narrow your eyes (like a relaxed smile), hold that squint for a beat, then let your eyes close gently for about a second. Reopen slowly. Repeat the sequence once or twice.
Step 4: Wait and watch.
Don't rush. Give your cat time to process and respond. A response may come immediately, or it might take 10–20 seconds. You may see a full slow blink back, a half-squint, a slight relaxation of their posture, or a turn of their head — all are positive responses.
Don't rush. Give your cat time to process and respond. A response may come immediately, or it might take 10–20 seconds. You may see a full slow blink back, a half-squint, a slight relaxation of their posture, or a turn of their head — all are positive responses.
Step 5: Don't force it.
If your cat looks away, moves, or simply doesn't respond, that's okay. Some cats are more demonstrative than others. The goal isn't a performance — it's a genuine exchange. Even unreturned slow blinks contribute to a feeling of safety over time.
If your cat looks away, moves, or simply doesn't respond, that's okay. Some cats are more demonstrative than others. The goal isn't a performance — it's a genuine exchange. Even unreturned slow blinks contribute to a feeling of safety over time.
What It Tells You About Your Cat's Inner World
One of the most exciting aspects of the slow blink research is what it implies about cat cognition and emotional awareness.
For a long time, cats were characterized as asocial, indifferent, or incapable of the kind of bonded communication we associate with dogs. The slow blink study challenges that directly.
To perform a slow blink in response to a human slow blink, a cat must:
- Perceive the human's facial expression
- Distinguish it from a neutral expression
- Recognize it as a social signal
- Choose to respond with a specific corresponding behavior
That's not reflexive. That's social cognition — the ability to read and respond to others' communicative intent. And it suggests that cats are paying far more attention to human facial expressions than most people assume.
Research by Moriah Galvan and Jennifer Vonk (2016) confirmed that cats can distinguish between happy and angry human facial expressions. Another study found that cats are sensitive to their owner's emotional state and actually behave differently when their owner appears stressed versus content.
Your cat knows more about you than you might think — and the slow blink is their way of letting you know they've been paying attention.
Pro Tips for Cat Parents
Use slow blinking during stressful moments. Vet visits, car rides, guests in the home — when your cat is in an unfamiliar or unsettling situation, a slow blink from you can serve as a real-time reassurance signal. It communicates you're safe, I'm calm, there's no threat without the need for words.
Introduce new people to your cat with slow blinking. Before a guest reaches toward your cat, suggest they try a slow blink. The study's stranger experiment suggests this can meaningfully increase a cat's willingness to approach an unfamiliar person — especially useful for cats who tend to be shy or hide with visitors.
Try it with cats you're meeting for the first time. Whether you're visiting a shelter, a friend's home, or meeting a new cat in any context, a slow blink is one of the kindest things you can offer. It signals that you're not a threat before any physical interaction happens.
Don't neglect the rest of your body language. Slow blinking works best in combination with a relaxed posture, a gentle voice, and non-looming body positioning. Crouch down or sit at the cat's level when you do it, rather than leaning over them from above.
Be patient with new cats. If you've recently adopted a cat and they aren't slow blinking back yet, don't worry. Building trust takes time, especially with cats who had uncertain earlier experiences. Keep offering the signal consistently — over weeks and months, you're building a vocabulary.
Frequently Asked Questions
Q: My cat blinks at me a lot — does that mean they love me?
A: A slow blink — deliberate, gradual, with a momentary close — is the meaningful signal. Regular quick blinks are just normal eye function. If your cat regularly gives you that soft, squinting, unhurried blink from across the room, yes — that's affection and trust in action.
A: A slow blink — deliberate, gradual, with a momentary close — is the meaningful signal. Regular quick blinks are just normal eye function. If your cat regularly gives you that soft, squinting, unhurried blink from across the room, yes — that's affection and trust in action.
Q: What if my cat never slow blinks?
A: Some cats are simply less expressive than others, and cats who came from stressful backgrounds may take longer to feel safe enough for this kind of vulnerable signaling. It doesn't mean they don't trust you. Watch for other relaxed behaviors: loose body posture, slow tail movements, kneading, rolling over to expose their belly. These are all parts of the same "I feel safe" communication system.
A: Some cats are simply less expressive than others, and cats who came from stressful backgrounds may take longer to feel safe enough for this kind of vulnerable signaling. It doesn't mean they don't trust you. Watch for other relaxed behaviors: loose body posture, slow tail movements, kneading, rolling over to expose their belly. These are all parts of the same "I feel safe" communication system.
Q: Can I teach my cat to slow blink?
A: In a sense. You can't train it like a trick, but you can cultivate it by consistently offering slow blinks yourself, especially in calm, low-stimulation moments. Over time, many cats begin to mirror the behavior more readily as it becomes a familiar, positive exchange in your relationship.
A: In a sense. You can't train it like a trick, but you can cultivate it by consistently offering slow blinks yourself, especially in calm, low-stimulation moments. Over time, many cats begin to mirror the behavior more readily as it becomes a familiar, positive exchange in your relationship.
Q: Does this work with kittens?
A: Yes — and starting early can help build a foundation of trust and positive communication. Kittens are in a critical socialization window (typically 2–7 weeks, extending somewhat longer) where positive human interactions shape their long-term temperament. Regular slow blinking during this period contributes to a calm, trusting adult cat.
A: Yes — and starting early can help build a foundation of trust and positive communication. Kittens are in a critical socialization window (typically 2–7 weeks, extending somewhat longer) where positive human interactions shape their long-term temperament. Regular slow blinking during this period contributes to a calm, trusting adult cat.
Q: Do cats slow blink at other cats too?
A: Yes. Slow blinking and eye-narrowing are part of the broader feline language of non-aggression and comfort. Cats in multi-cat households may use slow blinking with each other, particularly cats who have established a tolerant or bonded relationship. If you notice two cats slow blinking at each other, that's a good sign — they're at ease.
A: Yes. Slow blinking and eye-narrowing are part of the broader feline language of non-aggression and comfort. Cats in multi-cat households may use slow blinking with each other, particularly cats who have established a tolerant or bonded relationship. If you notice two cats slow blinking at each other, that's a good sign — they're at ease.
Q: I tried it and my cat yawned or looked away. Did I do it wrong?
A: Not necessarily. A yawn and look-away can actually be a cat's way of accepting a de-escalation signal — a visual equivalent of "message received, all good." It's also possible they just weren't in the mood. Try again in a quiet moment when your cat seems especially settled.
A: Not necessarily. A yawn and look-away can actually be a cat's way of accepting a de-escalation signal — a visual equivalent of "message received, all good." It's also possible they just weren't in the mood. Try again in a quiet moment when your cat seems especially settled.
The Takeaway: A Whole Conversation in One Blink
The next time your cat fixes you with that heavy, half-lidded gaze from across the room, you're not just looking at a tired animal. You're being addressed.
Cats evolved alongside humans for thousands of years — and in that time, they developed specific signals for managing their relationship with us. The slow blink is one of the most elegant: a tiny, quiet gesture that says I am not afraid of you. I choose to be here. I trust you.
When you slow blink back, you're speaking their language. You're saying the same thing.
That exchange — so small it almost doesn't register — is, in its way, everything. It's the whole point of sharing your life with an animal.
Sources
- Proops, L., Grounds, K., Smith, A.V., & McComb, K. (2020). Direct communication from domestic cats to their owners. Scientific Reports, 10, 4086. https://doi.org/10.1038/s41598-020-60855-6
- Vitale, K.R., Behnke, A.C., & Udell, M.A.R. (2019). Attachment bonds between domestic cats and humans. Current Biology, 29(18), R864–R865. https://doi.org/10.1016/j.cub.2019.08.036
- Galvan, M., & Vonk, J. (2016). Man's other best friend: domestic cats (F. silvestris catus) and their discrimination of human emotion cues. Animal Cognition, 19(1), 193–205. https://doi.org/10.1007/s10071-015-0927-4
- Turner, D.C. (2017). A review of over three decades of research on cat-human and human-cat interactions and relationships. Behavioural Processes, 141, 297–304. https://doi.org/10.1016/j.beproc.2017.02.004
- Bradshaw, J.W.S. (2016). Sociality in cats: A comparative review. Journal of Veterinary Behavior, 11, 113–124. https://doi.org/10.1016/j.jveb.2015.09.004
Note: This article is intended as general educational content about cat behavior. While the research cited is peer-reviewed and well-established, every cat is an individual. If your cat shows unusual behavioral changes or signs of anxiety, consult your veterinarian or a certified animal behaviorist.
Updated 8/11/26
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