< Updated 2026-08-16 >
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Scientists have been investigating a dog’s ability to recognize the emotional state of both other dogs and humans for several years. A paper published by iScience on August 10, 2026 [ Hernández-Pérez et al., 2026, iScience, 116900, 2026 © 2026 The Author(s). Published by Elsevier Inc – https://doi.org/10.1016/j.isci.2026.116900 ] has increased that knowledge as indicated below:

• By looking at our faces, dogs can determine whether we are happy or afraid. They can also tell if we are angry or sad, but the study did not indicate whether dogs can differentiate between the two. Further studies may indicate whether dogs use aspects of our body, other than our face, to assess whether we are sad or angry.
• When a dog sees a happy human face, it triggers activation in parts of their brain called the temporal cortex and caudate nucleus. The latter is the brain’s primary reward center, suggesting that a happy human face has emotional and motivational value for our dogs.
• The study also indicated that dogs could assess a person’s emotional states even if they were unfamiliar with the person.

So why is this important?

Over the years, I have spent countless hours training my own dogs, but even more time watching my students train theirs. The people who enjoyed working with their dogs were happy, and their dogs were happy, and learning occurred faster and more easily. When the people were unhappy, the dog was uncomfortable or stressed in their presence, and often no learning took place, frustrating both the people and their dog.

Other papers, listed below, have indicated dogs can discriminate between human faces expressing happiness and those expressing anger,^6,7 fear,⁸ sadness,⁹ disgust,¹⁰ or neutrality^11,12, as well as between angry^6,7 and neutral faces.¹²

• ⁶Albuquerque, N., Guo, K., Wilkinson, A., Savalli, C., Otta, E., and Mills, D. (2016). Dogs recognize dog and human emotions. Biol. Lett. 12, 20150883. https://doi.org/10.1098/rsbl.2015.0883.
• ⁷Müller, C.A., Schmitt, K., Barber, A.L.A., and Huber, L. (2015). Dogs can discriminate emotional expressions of human faces. Curr. Biol. 25, 601–605. https://doi.org/10.1016/j.cub.2014.12.055.
• ⁸Merola, I., Prato-Previde, E., Lazzaroni, M., and Marshall-Pescini, S. (2014). Dogs’ comprehension of referential emotional expressions: Familiar people and familiar emotions are easier. Anim. Cognit. 17, 373–385. https://doi.org/10.1007/s10071-013-0668-1.
• ⁹Morisaki, A., Takaoka, A., and Fujita, K. (2009). Are dogs sensitive to emotional state of humans? J. Vet. Behav. 4, 49. https://www.researchgate.net/publication/248577149_Are_dogs_sensitive_to_the_emotional_state_of_humans..
• ¹⁰Buttelmann, D., and Tomasello, M. (2013). Can domestic dogs (Canis familiaris) use referential emotional expressions to locate hidden food? Anim. Cognit. 16, 137–145. https://doi.org/10.1007/s10071-012-0560-4.
• ¹¹Nagasawa, M., Murai, K., Mogi, K., and Kikusui, T. (2011). Dogs can discriminate human smiling faces from blank expressions. Anim. Cognit. 14, 525–533. https://doi.org/10.1007/s10071-011-0386-5.
• ¹²Deputte, B.L., and Doll, A. (2011). Do dogs understand human facial expressions? J. Vet. Behav. 6, 78–79. https://www.researchgate.net/publication/241118368_Do_dogs_understand_human_facial_expressions

Articles in the Scientific Press About the Papers

• Dogs know when humans are happy—and it shows in their brains, By Jackie Flynn Mogensen, Scientific American – 2026-08-10 – https://www.scientificamerican.com/article/can-dogs-read-your-facial-expressions-it-depends-on-your-mood/
• Sad or afraid? Dogs may be able to read your face, By Meghan Rosen, ScienceNews – 2026-08-10 – https://www.sciencenews.org/article/dogs-understand-emotions-humans-face
• Dogs can distinguish between fearful and angry or sad human faces, brain scans suggest, The Guardian – 2026-08-10 – https://www.theguardian.com/world/2026/aug/10/dogs-distinguish-fearful-angry-sad-human-faces-brain-scans

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