A new study published this week in Scientific Reports suggests that pet ownership might play a protective role in slowing cognitive decline later in life. But before you rush out to buy a goldfish in hopes of sharpening your memory, it’s worth taking a closer look—because the kind of pet you have appears to matter.
Researchers Adriana Rostekova and colleagues examined 18 years of data from the Survey of Health, Ageing and Retirement in Europe (SHARE), focusing on adults aged 50 and older. Their goal was to better understand how pet ownership—specifically the type of pet—might be linked to changes in cognitive functioning over time. The study assessed two major domains of cognition: executive functioning (measured through verbal fluency tasks) and episodic memory (assessed through immediate and delayed recall tests).
Their findings? People who owned dogs or cats experienced a slower rate of cognitive decline than those who didn’t have pets. In contrast, owning birds or fish showed no meaningful association with cognitive outcomes.
The Species Difference: Dogs and Cats vs. Birds and Fish
This divergence between pet types is one of the most intriguing elements of the study. Dog and cat owners had higher baseline cognitive scores and experienced a more gradual decline across the study period. Fish and bird owners, however, didn’t differ significantly from non-pet owners in cognitive performance.
Why might that be?
One possibility is the difference in interaction. Dogs and cats typically offer rich, emotionally resonant, and physically engaging relationships. Dogs in particular promote physical activity—think daily walks—and facilitate social interactions with other people. Cats, while often more independent, still provide affection, companionship, and daily routines that can anchor mental activity.
In contrast, according to the study authors, fish and birds are generally lower-maintenance and less interactive. (Some fish and bird owners will no doubt take issue with this assumption!) Rostekova and colleagues suggest that while watching fish swim might be calming, and birds can be sociable and engaging in their own way, the level of physical activity, verbal communication, and emotional reciprocity is usually less than with dogs and cats. These differences may translate into less cognitive stimulation for their owners.
Correlation, Not Causation
It’s important to emphasize that this study does not prove that pets cause slower cognitive decline. The findings are correlational, meaning that while pet ownership is associated with better cognitive outcomes, we can’t say definitively that pets are the reason why.
It’s possible that people who are already healthier, more active, or more socially engaged are more likely to adopt pets—particularly dogs or cats. Likewise, individuals experiencing early signs of cognitive impairment might avoid the demands of dog ownership, skewing the data. The authors note these limitations, highlighting the need for further research that can tease apart causality.
A Fragmented Literature on Pets and Health
This study adds to a growing but inconsistent body of literature on the effects of pet ownership on human health—particularly mental and cognitive health. While some studies suggest that pets reduce loneliness, stress, and depression, others show little to no effect or even report negative impacts, such as grief after pet loss or stress associated with caregiving. Interestingly, a 2020 study found that among older adults in England, where the study took place, people with depressive symptoms were more likely to own a dog (Sharpley et al., 2020).
Moreover, few studies look at pet ownership over time or differentiate by species. The longitudinal design of this new study, with its 18-year follow-up period, is a major strength. Still, even here, the authors caution against overly simplistic interpretations.
The relationship between humans and their animal companions is complex and highly individualized. Factors such as the owner’s personality, physical health, living environment, cultural context, and the specific dynamics of the pet-human relationship all play a role. Pet ownership is not a one-size-fits-all health intervention.
The Takeaway
If you already have a dog or cat who brings you joy and companionship, this study offers one more reason to cherish that bond. It may not just be good for your mood—it could be good for your brain. But let’s pause there.
And as always with research into the health benefits of living with animals, I would caution that animals are sentient beings, not pharmaceutical interventions, and that the choice to bring an animal into our home should be grounded in an honest assessment of whether we are willing to do everything we can to provide an animal companion a full and meaningful life. Furthermore, adopting a pet is not a guaranteed cognitive shield. What works for one person might not work for another. The benefits of pet ownership likely depend on the quality of the relationship, the activities shared, and the owner’s capacity to care for the animal over time. Rather than viewing this study as just another notch in the belt of the so-called Pet Effect, I view it as a very interesting attempt to tease apart why certain humans find animal companionship so profoundly fulfilling.
The study also raises interesting questions about how we might support cognitive aging in more holistic, non-pharmaceutical ways. Should geriatric care plans include questions about pet ownership? Could community programs support older adults in maintaining bonds with companion animals? And might certain species or forms of interaction offer more “cognitive nourishment” than others, and why?
These are questions future studies might explore. For now, the takeaway is simple: Our relationships with animals—particularly dogs and cats—may do more than warm our hearts. They may help keep our minds sharp, too.
