Why Puppy-Dog Eyes Affect Us: What the Research Shows
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By Dr Duncan Houston
A raised inner eyebrow can make a dog's face look wide-eyed or plaintive to a person. That familiar puppy-dog expression has inspired research into anatomy, domestication and communication. The evidence is interesting, but more nuanced than a simple story about dogs evolving a special way to ask for love.
Quick Answer
Dogs can raise the inner part of the eyebrow using facial muscles, creating an expression many people find appealing. Research has explored whether human preferences shaped this movement, but later findings challenge claims that its muscle is unique to domestic dogs or that every eyebrow raise is intentional communication. Read the whole dog and situation rather than assigning one emotion to the face.
The anatomy behind the expression
The levator anguli oculi medialis, often shortened to LAOM, contributes to raising the inner eyebrow. A 2019 study compared facial anatomy and eyebrow movements in dogs and wolves. It reported differences and proposed that human preferences may have favoured expressive eyebrows during domestication.
That proposal is an evolutionary hypothesis, not direct observation of historical selection. The anatomical sample was small, and individuals and species can vary. It is not a basis for declaring that every dog has the same muscles or every wolf lacks the same movement.
Why later work matters
| Research question | What the findings suggest |
|---|---|
| Did dogs and wolves differ in an early comparison? | The 2019 study found anatomical and behavioural differences in its samples |
| Does an eyebrow raise always target a human observer? | A 2021 experiment linked the movement strongly with eye movements and did not find the predicted increase when a person was present |
| Is the relevant muscle exclusive to domestic dogs? | A 2024 study found a well-developed LAOM in coyotes, challenging a simple domestication-only account |
These studies address different parts of the question. Together they encourage caution about a single explanation. Finding a muscle tells us about possible movement; it does not by itself establish the animal's emotion or intention.
What the look means in everyday life
A dog may glance upwards while watching you, anticipating food or following something interesting. People may respond with attention, and ordinary learning can then shape interactions. That does not mean the dog is deliberately imitating a human baby or consciously manipulating your feelings.
Likewise, an appealing expression is not proof of sadness, guilt, hunger or a strong bond. Look for posture, movement, ear position, mouth tension, the ability to move away and what happened immediately beforehand.
Respond in a useful way
- Check practical needs such as toileting, comfortable rest and access to water.
- Offer interaction without insisting on prolonged eye contact.
- Reward calm communication and useful cues rather than giving extra food for every pleading look.
- Allow a dog to turn away, especially during close handling or greetings.
- Use several observations over time instead of interpreting a single photograph.
Staring can be uncomfortable in some contexts. A soft glance from a relaxed familiar dog is different from a fixed stare paired with stiffness or freezing. Children should not put their faces close to a dog's face to recreate a cute image.
When an eye change is medical
Squinting, redness, discharge, cloudiness, unequal pupils or a suddenly different expression may reflect an eye problem or pain. Do not assume the dog is simply being expressive. A painful eye, injury or sudden vision change needs prompt veterinary assessment.
Frequently asked questions
Are puppy-dog eyes unique to puppies?
No. Adult dogs can make the movement too.
Does my dog know the look makes me give treats?
Dogs can learn which behaviours lead to rewards, but a particular eyebrow movement does not reveal a specific thought.
Does a less expressive face mean a weaker bond?
No. Anatomy and individual behaviour vary, and attachment cannot be measured from eyebrows.
The expression can remain charming while we keep its scientific explanation appropriately open.
Further reading
- Kaminski and colleagues: facial muscle anatomy
- Bremhorst and colleagues: eyebrow and eye movements
- Coyotes and facial expression muscles
- RSPCA: dog body language
For more practical guidance on caring for your dog, explore ASK A VET™. If your dog needs urgent treatment, contact your veterinary clinic directly.
